研究者データベース

堀之内 武(ホリノウチ タケシ)
地球環境科学研究院 地球圏科学部門 大気海洋物理学分野
教授

基本情報

所属

  • 地球環境科学研究院 地球圏科学部門 大気海洋物理学分野

職名

  • 教授

学位

  • 博士(理学)(京都大学)

ホームページURL

J-Global ID

研究分野

  • 自然科学一般 / 大気水圏科学

職歴

  • 2020年06月 - 現在 北海道大学 大学院地球環境科学研究院 教授
  • 2008年10月 - 2020年05月 北海道大学 地球環境科学研究院 准教授
  • 2007年 - 2008年 京都大学 助教
  • 1999年 - 2007年 京都大学 助手
  • 1999年 - 2007年 Research Associate
  • 1997年 - 1999年 ワシントン大学 研究員
  • 1997年 - 1999年 Researcher,University of Washington

学歴

  •         - 1997年   京都大学   理学研究科   地球惑星科学専攻
  •         - 1997年   京都大学
  •         - 1994年   京都大学   理学研究科   地球惑星科学専攻
  •         - 1994年   京都大学

所属学協会

  • American Geophysical Union   地球電磁気・地球惑星圏学会   日本気象学会   

研究活動情報

論文

  • Yukiko Fujisawa, Shin-ya Murakami, Norihiko Sugimoto, Masahiro Takagi, Takeshi Imamura, Takeshi Horinouchi, George L. Hashimoto, Masaki Ishiwatari, Takeshi Enomoto, Takemasa Miyoshi, Hiroki Kashimura, Yoshi-Yuki Hayashi
    Scientific Reports 12 1 2022年08月26日 
    Abstract The planetary missions including the Venus Climate Orbiter ‘Akatsuki’ provide new information on various atmospheric phenomena. Nevertheless, it is difficult to elucidate their three-dimensional structures globally and continuously only from observations because satellite observations are considerably limited in time and space. We constructed the first ‘objective analysis’ of Venus’ atmosphere by assimilating cloud-top horizontal winds on the dayside from the equator to mid-latitudes, which is frequently obtained from Akatsuki's Ultraviolet Imager (UVI). The three-dimensional structures of thermal tides, found recently to play a crucial role in maintaining the super rotation, are greatly improved by the data assimilation. This result is confirmed by comparison with Akatsuki's temperature observations. The momentum transport caused by the thermal tides and other disturbances are also modified by the wind assimilation and agrees well with those estimated from the UVI observations. The assimilated dataset is reliable and will be open to the public along with the Akatsuki observations for further investigation of Venus’ atmospheric phenomena.
  • Wataru YANASE, Kentaro ARAKI, Akiyoshi WADA, Udai SHIMADA, Masahiro HAYASHI, Takeshi HORINOUCHI
    Journal of the Meteorological Society of Japan. Ser. II 2022年
  • Kiichi Fukuya, Takeshi Imamura, Makoto Taguchi, Tetsuya Fukuhara, Toru Kouyama, Takeshi Horinouchi, Javier Peralta, Masahiko Futaguchi, Takeru Yamada, Takao M. Sato, Atsushi Yamazaki, Shin-ya Murakami, Takehiko Satoh, Masahiro Takagi, Masato Nakamura
    Nature 595 7868 511 - 515 2021年07月22日 [査読有り]
     
    Although Venus is a terrestrial planet similar to Earth, its atmospheric circulation is much different and poorly characterized1. Winds at the cloud top have been measured predominantly on the dayside. Prominent poleward drifts have been observed with dayside cloud tracking and interpreted to be caused by thermal tides and a Hadley circulation2–4; however, the lack of nightside measurements over broad latitudes has prevented the unambiguous characterization of these components. Here we obtain cloud-tracked winds at all local times using thermal infrared images taken by the Venus orbiter Akatsuki, which is sensitive to an altitude of about 65 kilometres5. Prominent equatorward flows are found on the nightside, resulting in null meridional velocities when these are zonally averaged. The velocity structure of the thermal tides was determined without the influence of the Hadley circulation. The semidiurnal tide was found to have an amplitude large enough to contribute to the maintenance of the atmospheric superrotation. The weakness of the mean meridional flow at the cloud top implies that the poleward branch of the Hadley circulation exists above the cloud top and that the equatorward branch exists in the clouds. Our results should shed light on atmospheric superrotation in other celestial bodies.
  • Shinji Matsumura, Koji Yamazaki, Takeshi Horinouchi
    Geophysical Research Letters 48 11 2021年06月16日 [査読有り]
  • S. Tsujino, T. Horinouchi, T. Tsukada, H.-C. Kuo, H. Yamada, K. Tsuboki
    Journal of Geophysical Research: Atmospheres 126 7 2021年04月16日 [査読有り]
  • Takehiko Satoh, Choon Wei Vun, Masafumi Kimata, Takeshi Horinouchi, Takao M. Sato
    Icarus 355 114134 - 114134 2021年02月 [査読有り]
     
    We have developed a novel method called Restoration by Simple Subtraction (RSS) to clean and restore the Venus night-side disk in “contaminated” Akatsuki/IR2 images at 2.26 and 1.735 μm. Light spread from the intense day crescent is cancelled by subtracting a near-simultaneous 2.32-μm image (scaled) from a 2.26-μm image. Net-contamination over the night-side disk is effectively separated and subsequently used to clean a 1.735-μm image. For the first time ever, the IR2 night-side data have become of photometric quality. Ten data sets from Orbits 24 (August 16–20, 2016) and 25 (August 26–30, 2016) were processed by the RSS method and analyzed to study the aerosol properties and variations of low-altitude carbon monoxide (CO). A new coordinate system called “M3L” is introduced to interpret the data in terms of mixtures of different mode aerosols. No simultaneous increases/decreases in mode 3 and other modes were found, but they are rather anti-correlated, indicating interchanges between them in the Venus atmosphere. A prominent feature called clouds aligned linearly in M3L coordinates (CALM) is interpreted as an indicator of the most quiescent regions with gentle convection, which maintains the cloud microphysics (interchange between mode 3 and other modes plus sulfuric acid vapor) in an organized manner. The mid-latitude bright streaks are found to deviate from CALM, suggesting the existence of forced downwelling which was previously reported based on high-resolution numerical simulations. Latitudinal variations of mode mixtures as interpreted by the M3L coordinates were compared with those in the Venus Express observation-based studies. A common trend, more mode 3 particles near the equator, which decreases toward the middle latitudes, is observed despite a decade of difference in the observation periods. CO abundance in low latitude regions was found to be characterized either by a constant or with a possible local-time variation. Although statistically favored, controversial local-time variations of CO require further investigation.
  • Takeshi Horinouchi, Yu Kosaka, Hiroshi Nakamigawa, Hisashi Nakamura, Norihisa Fujikawa, Yukari N. Takayabu
    SOLA 17B Special{\_}Edition 1 - 8 2021年 [査読有り]
  • J. Peralta, T. Navarro, C. W. Vun, A. Sánchez‐Lavega, K. McGouldrick, T. Horinouchi, T. Imamura, R. Hueso, J. P. Boyd, G. Schubert, T. Kouyama, T. Satoh, N. Iwagami, E. F. Young, M. A. Bullock, P. Machado, Y. J. Lee, S. S. Limaye, M. Nakamura, S. Tellmann, A. Wesley, P. Miles
    Geophysical Research Letters 47 11 2020年06月16日 [査読有り]
  • Taiga Tsukada, Takeshi Horinouchi
    Geophysical Research Letters 47 11 2020年06月16日 [査読有り]
  • Takeshi Horinouchi, Yoshi-Yuki Hayashi, Shigeto Watanabe, Manabu Yamada, Atsushi Yamazaki, Toru Kouyama, Makoto Taguchi, Tetsuya Fukuhara, Masahiro Takagi, Kazunori Ogohara, Shin-ya Murakami, Javier Peralta, Sanjay S. Limaye, Takeshi Imamura, Masato Nakamura, Takao M. Sato, Takehiko Satoh
    Science 368 6489 405 - 409 2020年04月24日 [査読有り]
  • Takeshi Horinouchi, Udai Shimada, Akiyoshi Wada
    Geophysical Research Letters 47 3 2020年02月16日 [査読有り]
  • J. Peralta, A. Sánchez-Lavega, T. Horinouchi, K. McGouldrick, I. Garate-Lopez, E.F. Young, M.A. Bullock, Y.J. Lee, T. Imamura, T. Satoh, S.S. Limaye
    Icarus 333 177 - 182 2019年11月
  • Masataka Imai, Toru Kouyama, Yukihiro Takahashi, Atsushi Yamazaki, Shigeto Watanabe, Manabu Yamada, Takeshi Imamura, Takehiko Satoh, Masato Nakamura, Shin‐ya Murakami, Kazunori Ogohara, Takeshi Horinouchi
    Journal of Geophysical Research: Planets 2019年10月31日 [査読有り][通常論文]
  • T. Kouyama, M. Taguchi, T. Fukuhara, T. Imamura, T. Horinouchi, T. M. Sato, S. Murakami, G. L. Hashimoto, Y. J. Lee, M. Futaguchi, T. Yamada, M. Akiba, T. Satoh, M. Nakamura
    Geophysical Research Letters 46 16 9457 - 9465 2019年08月28日 [査読有り][通常論文]
  • Yeon Joo Lee, Kandis-Lea Jessup, Santiago Perez-Hoyos, Dmitrij V. Titov, Sebastien Lebonnois, Javier Peralta, Takeshi Horinouchi, Takeshi Imamura, Sanjay Limaye, Emmanuel Marcq, Masahiro Takagi, Atsushi Yamazaki, Manabu Yamada, Shigeto Watanabe, Shin-ya Murakami, Kazunori Ogohara, William M. McClintock, Gregory Holsclaw, Anthony Roman
    The Astronomical Journal 158 3 126 - 126 2019年08月26日 [査読有り]
  • Takehiko Kitahara, Takeshi Imamura, Takao M. Sato, Atsushi Yamazaki, Yeon Joo Lee, Manabu Yamada, Shigeto Watanabe, Makoto Taguchi, Tetsuya Fukuhara, Toru Kouyama, Shin‐ya Murakami, George L. Hashimoto, Kazunori Ogohara, Hiroki Kashimura, Takeshi Horinouchi, Masahiro Takagi
    Journal of Geophysical Research: Planets 2019年05月15日 [査読有り][通常論文]
  • Shinji Matsumura, Satoaki Ueki, Takeshi Horinouchi
    Geophysical Research Letters 46 7 3973 - 3981 2019年04月16日 [査読有り]
  • Takeshi Horinouchi, Shinji Matsumura, Tomoaki Ose, Yukari N. Takayabu
    Journal of Climate 32 8 2247 - 2259 2019年04月15日 [査読有り]
     
    Abstract Through extensive modeling efforts, it has been established that the ongoing global warming will increase the overall precipitation associated with the East Asian summer monsoon, but the future change of its spatial distribution has not reached a consensus. In this study, meridional shifts of the mei-yu–baiu rainband are studied in association with the subtropical jet by using outputs from atmosphere–ocean coupled climate models provided by CMIP5. The models reproduce observed associations between the jet and precipitation over wide time scales from synoptic to interannual. The same relation is found in intermodel differences in simulated climatology, so that the meridional locations of the jet and baiu precipitation are positively correlated. The multimodel-mean projection suggests that the both are shifted southward by the late twenty-first century. This shift is not inconsistent with the projected tropical expansion, not only because the change is local but also because the projected tropical expansion occurs mainly in the Southern Hemisphere. No significant future change in the continental mei-yu precipitation location is identified, which might be because the jet change is weak there. For comparison, the summertime Atlantic jet position, which shifts northward, is investigated briefly. This study suggests that the future change of the subtropical jet is an important aspect to investigate possible future changes of the baiu rainband, and it prompts further studies including the role of the ocean.
  • Masaru Yamamoto, Kohei Ikeda, Masaaki Takahashi, Takeshi Horinouchi
    Icarus 321 232 - 250 Elsevier {BV} 2019年03月 [査読有り][通常論文]
     
    Solar-locked and geographical atmospheric structures of daily averaged wind and temperature on Venus were investigated using an atmospheric general circulation model with Venusian topography and a two-stream radiative code and were compared with wind fields obtained from the Akatsuki ultraviolet imager. The horizontal wind fields simulated around the subsolar region are similar to the observed ones at the cloud top. Mid-latitude jets of similar to 120 m s(-1) and an equatorial fast flow of similar to 90 m s(-1) are formed around the cloud top. A poleward flow of > 8 m s(-1) is formed above the cloud layer, where solar heating is strong. Around the cloud top, a poleward flow of similar to 1 m s(-1) is confined within the equatorward flank of the jet core, whereas an indirect circulation is formed in the jet core by the eddy heat fluxes owing to the thermal tide and baroclinic waves. In solar-fixed coordinates, the subsolar-to-antisolar circulation is predominant around the cloud top. Thus, differences are significant between the zonal and dayside averages of the meridional wind and its related fluxes within the cloud layer. This suggests the zonal mean meridional wind of the Hadley circulation, eddy momentum, and heat fluxes from the one-side hemisphere must be estimated carefully. In the experiment including topography, a near-surface sub-rotation is formed in latitudinal zones over high land and mountains, a weakly stable layer is formed at 10-20 km at low latitudes, and the zonal wind is weakened at the cloud top over the Aphrodite Terra. Regional stationary modification of the atmospheric structure due to topographical waves appears in the cloud layer.
  • Atsushi Yamazaki, Manabu Yamada, Yeon Joo Lee, Shigeto Watanabe, Takeshi Horinouchi, Shin-ya Murakami, Toru Kouyama, Kazunori Ogohara, Takeshi Imamura, Takao M. Sato, Yukio Yamamoto, Tetsuya Fukuhara, Hiroki Ando, Ko-ichiro Sugiyama, Seiko Takagi, Hiroki Kashimura, Shoko Ohtsuki, Naru Hirata, George L. Hashimoto, Makoto Suzuki, Chikako Hirose, Munetaka Ueno, Takehiko Satoh, Takumi Abe, Nobuaki Ishii, Masato Nakamura
    Earth, Planets and Space 70 1 2018年12月01日 [査読有り][通常論文]
     
    The ultraviolet imager (UVI) has been developed for the Akatsuki spacecraft (Venus Climate Orbiter mission). The UVI takes ultraviolet (UV) images of the solar radiation reflected by the Venusian clouds with narrow bandpass filters centered at the 283 and 365 nm wavelengths. There are absorption bands of SO2 and unknown absorbers in these wavelength regions. The UV images provide the spatial distribution of SO2 and the unknown absorber around cloud top altitudes. The images also allow us to understand the cloud top morphologies and haze properties. Nominal sequential images with 2-h intervals are used to understand the dynamics of the Venusian atmosphere by estimating the wind vectors at the cloud top altitude, as well as the mass transportation of UV absorbers. The UVI is equipped with off-axial catadioptric optics, two bandpass filters, a diffuser installed in a filter wheel moving with a step motor, and a high sensitivity charge-coupled device with UV coating. The UVI images have spatial resolutions ranging from 200 m to 86 km at sub-spacecraft points. The UVI has been kept in good condition during the extended interplanetary cruise by carefully designed operations that have maintained its temperature maintenance and avoided solar radiation damage. The images have signal-to-noise ratios of over 100 after onboard desmear processing. [Figure not available: see fulltext.].
  • Javier Peralta, Keishiro Muto, Ricardo Hueso, Takeshi Horinouchi, Agust{\'{\i, S{\'{a } }nchez-Lavega, Shin-ya Murakami, Pedro Machado, Eliot F. Young, Yeon Joo Lee, Toru Kouyama, Hideo Sagawa, Kevin McGouldrick, Takehiko Satoh, Takeshi Imamura, Sanjay S. Limaye, Takao M. Sato, Kazunori Ogohara, Masato Nakamura, David Luz
    The Astrophysical Journal Supplement Series 239 2 29 - 29 American Astronomical Society 2018年12月 [査読有り][通常論文]
  • Takeshi Horinouchi, Toru Kouyama, Yeon Joo Lee, Shin-ya Murakami, Kazunori Ogohara, Masahiro Takagi, Takeshi Imamura, Kensuke Nakajima, Javier Peralta, Atsushi Yamazaki, Manabu Yamada, Shigeto Watanabe
    Earth, Planets and Space 70 1 2018年12月01日 [査読有り][通常論文]
     
    Venus is covered with thick clouds. Ultraviolet (UV) images at 0.3–0.4 microns show detailed cloud features at the cloud-top level at about 70 km, which are created by an unknown UV-absorbing substance. Images acquired in this wavelength range have traditionally been used to measure winds at the cloud top. In this study, we report low-latitude winds obtained from the images taken by the UV imager, UVI, onboard the Akatsuki orbiter from December 2015 to March 2017. UVI provides images with two filters centered at 365 and 283 nm. While the 365-nm images enable continuation of traditional Venus observations, the 283-nm images visualize cloud features at an SO2 absorption band, which is novel. We used a sophisticated automated cloud-tracking method and thorough quality control to estimate winds with high precision. Horizontal winds obtained from the 283-nm images are generally similar to those from the 365-nm images, but in many cases, westward winds from the former are faster than the latter by a few m/s. From previous studies, one can argue that the 283-nm images likely reflect cloud features at higher altitude than the 365-nm images. If this is the case, the superrotation of the Venusian atmosphere generally increases with height at the cloud-top level, where it has been thought to roughly peak. The mean winds obtained from the 365-nm images exhibit local time dependence consistent with known tidal features. Mean zonal winds exhibit asymmetry with respect to the equator in the latter half of the analysis period, significantly at 365 nm and weakly at 283 nm. This contrast indicates that the relative altitude may vary with time and latitude, and so are the observed altitudes. In contrast, mean meridional winds do not exhibit much long-term variability. A previous study suggested that the geographic distribution of temporal mean zonal winds obtained from UV images from the Venus Express orbiter during 2006–2012 can be interpreted as forced by topographically induced stationary gravity waves. However, the geographic distribution of temporal mean zonal winds we obtained is not consistent with that distribution, which suggests that the distribution may not be persistent.
  • Shimada Udai, Horinouchi Takeshi
    Monthly Weather Review 146 9 2799 - 2817 2018年 [査読有り][通常論文]
  • Sanjay S. Limaye, Shigeto Watanabe, Atsushi Yamazaki, Manabu Yamada, Takehiko Satoh, Masato Nakamura, Makoto Taguchi, Tetsuya Fukuhara, Takeshi Imamura, Toru Kouyama, Yeon Joo Lee, Takeshi Horinouchi, Javier Peralta, Naomoto Iwagami, George L. Hashimoto, Seiko Takagi, Shoko Ohtsuki, Shin-ya Murakami, Yukio Yamamoto, Kazunori Ogohara, Hiroki Ando, Ko-ichiro Sugiyama, Nobuaki Ishii, Takumi Abe, Chikako Hirose, Makoto Suzuki, Naru Hirata, Eliot F. Young, Adriana C. Ocampo
    Earth, Planets and Space 70 1 2018年 [査読有り][通常論文]
     
    Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths from ultraviolet (283 and 365 nm) and near infrared (0.9–2.3 µm), to the thermal infrared (8–12 µm) from a near-equatorial orbit. The Venus Express and Pioneer Venus Orbiter missions have also monitored the planet for long periods but from polar or near-polar orbits. The wavelength coverage and views of the planet also differ for all three missions. In reflected light, the images reveal features seen near the cloud tops (~ 70 km altitude), whereas in the near-infrared images of the nightside, features seen are at mid- to lower cloud levels (~ 48–60 km altitude). The dayside cloud cover imaged at the ultraviolet wavelengths shows morphologies similar to what was observed from Mariner 10, Pioneer Venus, Galileo, Venus Express and MESSENGER. The daytime images at 0.9 and 2.02 µm also reveal some interesting features which bear similarity to the ultraviolet images. The nighttime images at 1.74, 2.26 and 2.32 µm and at 8–12 µm reveal features not seen before and show new details of the nightside including narrow wavy ribbons, curved string-like features, long-scale waves, long dark streaks, isolated bright spots, sharp boundaries and even mesoscale vortices. Some features previously seen such as circum-equatorial belts (CEBs) and occasional areal brightenings at ultraviolet (seen in Venus Express observations) of the cloud cover at ultraviolet wavelengths have not been observed thus far. Evidence for the hemispheric vortex organization of the global circulation can be seen at all wavelengths on the day- and nightsides. Akatsuki images reveal new and puzzling morphology of the complex nightside cloud cover. The cloud morphologies provide some clues to the processes occurring in the atmosphere and are thus, a key diagnostic tool when quantitative dynamical analysis is not feasible due to insufficient information.[Figure not available: see fulltext.].
  • T. Kouyama, T. Imamura, M. Taguchi, T. Fukuhara, T. M. Sato, A. Yamazaki, M. Futaguchi, S. Murakami, G. L. Hashimoto, M. Ueno, N. Iwagami, S. Takagi, M. Takagi, K. Ogohara, H. Kashimura, T. Horinouchi, N. Sato, M. Yamada, Y. Yamamoto, S. Ohtsuki, K. Sugiyama, H. Ando, M. Takamura, T. Yamada, T. Satoh, M. Nakamura
    Geophysical Research Letters 44 24 12 - 105 2017年12月28日 [査読有り][通常論文]
     
    The existence of large stationary gravity waves was discovered during Akatsuki's first observation sequence in 2015. In this study, the further detection of large stationary gravity waves in brightness temperature images over a 1.5 year period is reported. The waves periodically appeared mostly above four specific highland regions in the low latitudes when these regions were in the local afternoon. The wave amplitudes attenuated after the wave locations passed beyond the evening terminator, and the locations of the waves tended to slowly drift eastward over their lifetimes. The appearances of stationary waves depend not only on surface topography but also on latitude and local time, suggesting that solar heating during the daytime and atmospheric structure affected by solar heating may control the excitation and propagation of stationary waves.
  • Takehiko Satoh, Takao M. Sato, Masato Nakamura, Yasumasa Kasaba, Munetaka Ueno, Makoto Suzuki, George L. Hashimoto, Takeshi Horinouchi, Takeshi Imamura, Atsushi Yamazaki, Takayuki Enomoto, Yuri Sakurai, Kosuke Takami, Kenta Sawai, Takashi Nakakushi, Takumi Abe, Nobuaki Ishii, Chikako Hirose, Naru Hirata, Manabu Yamada, Shin-ya Murakami, Yukio Yamamoto, Tetsuya Fukuhara, Kazunori Ogohara, Hiroki Ando, Ko-ichiro Sugiyama, Hiroki Kashimura, Shoko Ohtsuki
    EARTH PLANETS AND SPACE 69 2017年11月 [査読有り][通常論文]
     
    The first year (December 2015 to November 2016) of IR2 after Akatsuki's successful insertion to an elongated elliptical orbit around Venus is reported with performance evaluation and results of data acquisition. The single-stage Stirling-cycle cryo-cooler of IR2 has been operated with various driving voltages to achieve the best possible cooling under the given thermal environment. A total of 3091 images of Venus (1420 dayside images at 2.02 mu m and 1671 night-side images at 1.735, 2.26, and 2.32 mu m) were acquired in this period. Additionally, 159 images, including images of stars for calibration and dark images for the evaluation of noise levels, were captured. Low-frequency flat images (not available in pre-launch calibration data) have been constructed using the images of Venus acquired from near the pericenter to establish the procedure to correct for the IR2 flat-field response. It was noticed that multiple reflections of infrared light in the PtSi detector caused a weak but extended tail of the point-spread function (PSF), contaminating the night-side disk of Venus with light from the much brighter dayside crescent. This necessitated the construction of an empirical PSF to remove this contamination and also to improve the dayside data by deconvolution, and this work is also discussed. Detailed astrometry is performed on star-field images in the H-band (1.65 mu m), hereby confirming that the geometrical distortion of IR2 images is negligible.
  • Chie Yokoyama, Yukari N. Takayabu, Takeshi Horinouchi
    JOURNAL OF CLIMATE 30 20 8127 - 8147 2017年10月 [査読有り][通常論文]
     
    A quasi-stationary front, called the baiu front, often appears during the early-summer rainy season in East Asia (baiu in Japan). The present study examines how precipitation characteristics during the baiu season are determined by the large-scale environment, using satellite observation three-dimensional precipitation data. Emphasis is placed on the effect of subtropical jet (STJ) and lower-tropospheric convective instability (LCI). A rainband appears together with a deep moisture convergence to the south of the STJ. Two types of mesoscale rainfall events (REs; contiguous rainfall areas), which are grouped by the stratiform precipitation ratio (SPR; stratiform precipitation over total precipitation), are identified: moderately stratiform REs (SPR of 0%-80%) representing tropical organized precipitation systems and highly stratiform REs (SPR of 80%-100%) representing midlatitude precipitation systems associated with extratropical cyclones. As the STJ becomes strong, rainfall from both types of mesoscale precipitation systems increases, with a distinct eastward extension of a midtropospheric moist region. In contrast, small systems appear regardless of the STJ, with high dependency on the LCI. The results indicate that the STJ plays a role in moistening the midtroposphere owing to ascent associated with secondary circulation to the south of the STJ, producing environments favorable for organized precipitation systems in the southern part of the rainband. The horizontal moisture flux convergence may also contribute to precipitation just along the STJ. On the other hand, the LCI plays a role in generating shallow convection. In high-LCI conditions, deep convection can occur without the aid of mesoscale organization.
  • Takeshi Horinouchi, Shin-ya Murakami, Toru Kouyama, Kazunori Ogohara, Atsushi Yamazaki, Manabu Yamada, Shigeto Watanabe
    MEASUREMENT SCIENCE AND TECHNOLOGY 28 8 2017年08月 [査読有り][通常論文]
     
    Correlation-based cloud tracking has been extensively used to measure atmospheric winds, but still difficulty remains. In this study, aiming at developing a cloud tracking system for Akatsuki, an artificial satellite orbiting Venus, a formulation is developed for improving the relaxation labeling technique to select appropriate peaks of cross-correlation surfaces which tend to have multiple peaks. The formulation makes an explicit use of consistency inherent in the type of cross-correlation method where template sub-images are slid without deformation; if the resultant motion vectors indicate a too-large deformation, it is contradictory to the assumption of the method. The deformation consistency is exploited further to develop two post processes; one clusters the motion vectors into groups within each of which the consistency is perfect, and the other extends the groups using the original candidate lists. These processes are useful to eliminate erroneous vectors, distinguish motion vectors at different altitudes, and detect phase velocities of waves in fluids such as atmospheric gravity waves. As a basis of the relaxation labeling and the post processes as well as uncertainty estimation, the necessity to find isolated (well-separated) peaks of cross-correlation surfaces is argued, and an algorithm to realize it is presented. All the methods are implemented, and their effectiveness is demonstrated with initial images obtained by the ultraviolet imager onboard Akatsuki. Since the deformation consistency regards the logical consistency inherent in template matching methods, it should have broad application beyond cloud tracking.
  • J. Peralta, Y. J. Lee, R. Hueso, R. T. Clancy, B. J. Sandor, A. Sanchez-Lavega, E. Lellouch, M. Rengel, P. Machado, M. Omino, A. Piccialli, T. Imamura, T. Horinouchi, S. Murakami, K. Ogohara, D. Luz, D. Peach
    GEOPHYSICAL RESEARCH LETTERS 44 8 3907 - 3915 2017年04月 [査読有り][通常論文]
     
    Even though many missions have explored the Venus atmospheric circulation, its instantaneous state is poorly characterized. In situ measurements vertically sampling the atmosphere exist for limited locations and dates, while remote sensing observations provide only global averages of winds at altitudes of the clouds: 47, 60, and 70 km. We present a three-dimensional global view of Venus's atmospheric circulation from data obtained in June 2007 by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Venus Express spacecrafts, together with ground-based observations. Winds and temperatures were measured for heights 47-110 km from multiwavelength images and spectra covering 40 degrees N-80 degrees S and local times 12 h-21 h. Dayside westward winds exhibit day-to-day changes, with maximum speeds ranging 97-143 m/s and peaking at variable altitudes within 75-90 km, while on the nightside these peak below cloud tops at similar to 60 km. Our results support past reports of strong variability of the westward zonal superrotation in the transition region, and good agreement is found above the clouds with results from the Laboratoire de Meteorologie Dynamique (LMD) Venus general circulation model.
  • Takeshi Horinouchi, Ayumu Hayashi
    JOURNAL OF THE ATMOSPHERIC SCIENCES 74 4 1233 - 1247 2017年04月 [査読有り][通常論文]
     
    It has been revealed that in summertime, precipitation is enhanced to the south of the upper-level tropopausal potential vorticity contours, which are accompanied by instantaneous jets, over the eastern coastal region of China to the northwestern Pacific. It is frequently exhibited as precipitation bands ranging in size from over a thousand to several thousands of kilometers long. In this study, an analysis was conducted to quantify the relationship depending on the phase of upper-level disturbances. With composite analysis, it is shown that the enhancement along the contours occurs at all phases; it occurs not only to the east but also to the west of the upper-level troughs, although it is weaker. The midtropospheric distributions of upwelling and the Q-vector convergence are collocated with the precipitation enhancement, suggesting the importance of dynamical induction by geostrophic flow at all phases. The effects of upper-level disturbances and low-level jets (LLJs) with a southerly component are investigated by using an idealized nondimensional quasigeostrophic model supporting latent heating. While upper-level waves induce upwelling and downwelling to the east and west, respectively, of the upper-level troughs, LLJs tend to offset the downwelling, enabling precipitation to the west too. Both in the observational composite and the idealized model with LLJ, confluence and diffluence contribute to the Q-vector convergence to induce upwelling along the subtropical jet irrespective of upper-level disturbance phases. This induction is explained as a general feature of a veered jet where geopotential isolines rotate clockwise with height without requiring wind variation along the jet.
  • Tetsuya Fukuhara, Masahiko Futaguchi, George L. Hashimoto, Takeshi Horinouchi, Takeshi Imamura, Naomoto Iwagaimi, Toru Kouyama, Shin-ya Murakami, Masato Nakamura, Kazunori Ogohara, Mitsuteru Sato, Takao M. Sato, Makoto Suzuki, Makoto Taguchi, Seiko Takagi, Munetaka Ueno, Shigeto Watanabe, Manabu Yamada, Atsushi Yamazaki
    NATURE GEOSCIENCE 10 2 85 - + 2017年02月 [査読有り][通常論文]
     
    The planet Venus is covered by thick clouds of sulfuric acid that move westwards because the entire upper atmosphere rotates much faster than the planet itself. At the cloud tops, about 65 km in altitude, small-scale features are predominantly carried by the background wind at speeds of approximately 100 ms(-1). In contrast, planetary-scale atmospheric features have been observed to move slightly faster or slower than the background wind, a phenomenon that has been interpreted to reflect the propagation of planetary-scale waves. Here we report the detection of an interhemispheric bow-shaped structure stretching 10,000 km across at the cloud-top level of Venus in middle infrared and ultraviolet images from the Japanese orbiter Akatsuki. Over several days of observation, the bow-shaped structure remained relatively fixed in position above the highland on the slowly rotating surface, despite the background atmospheric super rotation. We suggest that the bow-shaped structure is the result of an atmospheric gravity wave generated in the lower atmosphere by mountain topography that then propagated upwards. Numerical simulations provide preliminary support for this interpretation, but the formation and propagation of a mountain gravity wave remain difficult to reconcile with assumed near-surface conditions on Venus. We suggest that winds in the deep atmosphere may be spatially or temporally more variable than previously thought.
  • Horinouchi T, Murakami S. Y, Satoh T, Peralta J, Ogohara K, Kouyama T, Imamura T, Kashimura H, Limaye S. S, McGouldrick K, Nakamura M, Sato T. M, Sugiyama K. I, Takagi M, Watanabe S, Yamada M, Yamazaki A, Young E. F
    Nature Geoscience 10 10 798  2017年 [査読有り][通常論文]
  • Horinouchi T, Murakami S, Satoh T, Peralta J, Ogohara K, Kouyama T, Imamura T, Kashimura H, Limaye S. S, McGouldrick K, Nakamura M, Sato T. M, Sugiyama K, Takagi M, Watanabe S, Yamada M, Yamazaki A, Young E. F
    Nature Geoscience 10 9 646 - + 2017年 [査読有り][通常論文]
  • A. Sanchez-Lavega, J. Peralta, J. M. Gomez-Forrellad, R. Hueso, S. Perez-Hoyos, I. Mendikoa, J. F. Rojas, T. Horinouchi, Y. J. Lee, S. Watanabe
    ASTROPHYSICAL JOURNAL LETTERS 833 1 2016年12月 [査読有り][通常論文]
     
    We report Venus image observations around the two maximum elongations of the planet at 2015 June and October. From these images we describe the global atmospheric dynamics and cloud morphology in the planet before the arrival of JAXA's Akatsuki mission on 2015 December 7. The majority of the images were acquired at ultraviolet wavelengths (380-410 nm) using small telescopes. The Venus dayside was also observed with narrowband filters at other wavelengths (890 nm, 725-950 nm, 1.435 mu m CO2 band) using the instrument PlanetCam-UPV/EHU at the 2.2 m telescope in Calar Alto Observatory. In all cases, the lucky imaging methodology was used to improve the spatial resolution of the images over the atmospheric seeing. During the April-June period, the morphology of the upper cloud showed an irregular and chaotic texture with a well-developed equatorial dark belt (afternoon hemisphere), whereas during October-December the dynamical regime was dominated by planetary-scale waves (Y-horizontal, C-reversed, and psi-horizontal features) formed by long streaks, and banding suggesting more stable conditions. Measurements of the zonal wind velocity with cloud tracking in the latitude range from 50 degrees N to 50 degrees S shows agreement with retrievals from previous works.
  • Shinji Matsumura, Takeshi Horinouchi
    SCIENTIFIC REPORTS 6 2016年11月 [査読有り][通常論文]
     
    The western Pacific subtropical high (WPSH) has a significant effect on droughts, heat waves, and tropical cyclone tracks over East Asia and the northwest Pacific. The WPSH has intensified during the past three decades, but its causes are not yet well understood. Here we show that the Pacific Decadal Oscillation (PDO) is responsible for the long-term changes in the WPSH through the meridional shift of the subtropical jet, based on comprehensive data analysis and model results. El Nino-Southern Oscillation (ENSO) is the leading forcing of WPSH variability over interannual timescales, whereas the PDO accounts for its low-frequency variability, resulting in it being independent of ENSO with regard to WPSH variability. The PDO in summer can be interpreted as a coupling with the WPSH. Our results provide useful information for projecting long-term changes in the WPSH.
  • Shinichi Ikegawa, Takeshi Horinouchi
    ICARUS 271 98 - 119 2016年06月 [査読有り][通常論文]
     
    Accurate wind observation is a key to study atmospheric dynamics. A new automated cloud tracking method for the dayside of Venus is proposed and evaluated by using the ultraviolet images obtained by the Venus Monitoring Camera onboard the Venus Express orbiter. It uses multiple images obtained successively over a few hours. Cross-correlations are computed from the pair combinations of the images and are superposed to identify cloud advection. It is shown that the superposition improves the accuracy of velocity estimation and significantly reduces false pattern matches that cause large errors. Two methods to evaluate the accuracy of each of the obtained cloud motion vectors are proposed. One relies on the confidence bounds of cross-correlation with consideration of anisotropic cloud morphology. The other relies on the comparison of two independent estimations obtained by separating the successive images into two groups. The two evaluations can be combined to screen the results. It is shown that the accuracy of the screened vectors are very high to the equatorward of 30 degree, while it is relatively low at higher latitudes. Analysis of them supports the previously reported existence of day-to-day large-scale variability at the cloud deck of Venus, and it further suggests smaller-scale features. The product of this study is expected to advance the dynamics of venusian atmosphere. (C) 2016 Elsevier Inc. All rights reserved.
  • Masato Nakamura, Takeshi Imamura, Nobuaki Ishii, Takumi Abe, Yasuhiro Kawakatsu, Chikako Hirose, Takehiko Satoh, Makoto Suzuki, Munetaka Ueno, Atsushi Yamazaki, Naomoto Iwagami, Shigeto Watanabe, Makoto Taguchi, Tetsuya Fukuhara, Yukihiro Takahashi, Manabu Yamada, Masataka Imai, Shoko Ohtsuki, Kazunori Uemizu, George L. Hashimoto, Masahiro Takagi, Yoshihisa Matsuda, Kazunori Ogohara, Naoki Sato, Yasumasa Kasaba, Toru Kouyama, Naru Hirata, Ryosuke Nakamura, Yukio Yamamoto, Takeshi Horinouchi, Masaru Yamamoto, Yoshi-Yuki Hayashi, Hiroki Kashimura, Ko-ichiro Sugiyama, Takeshi Sakanoi, Hiroki Ando, Shin-ya Murakami, Takao M. Sato, Seiko Takagi, Kensuke Nakajima, Javier Peralta, Yeon Joo Lee, Junichi Nakatsuka, Tsutomu Ichikawa, Kozaburo Inoue, Tomoaki Toda, Hiroyuki Toyota, Sumitaka Tachikawa, Shinichiro Narita, Tomoko Hayashiyama, Akiko Hasegawa, Yukio Kamata
    EARTH PLANETS AND SPACE 68 2016年05月 [査読有り][通常論文]
     
    AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate the climate system of Venus. The orbiter was launched on May 21, 2010, and it reached Venus on December 7, 2010. Thrust was applied by the orbital maneuver engine in an attempt to put AKATSUKI into a westward equatorial orbit around Venus with a 30-h orbital period. However, this operation failed because of a malfunction in the propulsion system. After this failure, the spacecraft orbited the Sun for 5 years. On December 7, 2015, AKATSUKI once again approached Venus and the Venus orbit insertion was successful, whereby a westward equatorial orbit with apoapsis of similar to 440,000 km and orbital period of 14 days was initiated. Now that AKATSUKI's long journey to Venus has ended, it will provide scientific data on the Venusian climate system for two or more years. For the purpose of both decreasing the apoapsis altitude and avoiding a long eclipse during the orbit, a trim maneuver was performed at the first periapsis. The apoapsis altitude is now similar to 360,000 km with a periapsis altitude of 1000-8000 km, and the period is 10 days and 12 h. In this paper, we describe the details of the Venus orbit insertion-revenge 1 (VOI-R1) and the new orbit, the expected scientific information to be obtained at this orbit, and the Venus images captured by the onboard 1-mu m infrared camera, ultraviolet imager, and long-wave infrared camera 2 h after the successful initiation of the VOI-R1.
  • Shinji Matsumura, Takeshi Horinouchi, Shiori Sugimoto, Tomonori Sato
    JOURNAL OF CLIMATE 29 8 3075 - 3093 2016年04月 [査読有り][通常論文]
     
    The Pacific Japan (PJ) teleconnection pattern leads to a meridional precipitation dipole between the subtropics and East Asia in the summer of El Nino decaying years. However, observational analysis and model experiments indicate that increased sea surface temperature (SST) in the Kuroshio Oyashio Extension (KOE) region, where a strong northward-decreasing SST gradient occurs, induces a northward shift of baiu rainfall with the subtropical jet, forming a tripolar precipitation anomaly pattern over the northwest Pacific. In July, the leading empirical orthogonal function (EOF) mode for precipitation represents the meridional dipole between subtropical and baiu rainfalls, while EOF-2 features the northward-shifted baiu rainband. The PJ atmospheric forcing increases KOE SST, which enhances northward shifts in the subtropical jet and baiu rainband, resulting in oceanic forcing over the KOE. In experiments using a regional climate model the subtropical jet response to KOE SST forcing explains about 20% of the anomalies in the control experiment. The northward-shifted baiu condensational heating also enhances the northward shift of the subtropical jet with a northeastward extension. In August when the baiu rainband disappears, the northward shift of the subtropical jet is enhanced mainly by KOE SST variability. During the summer, as a result of increased KOE SST and the northward-shifted baiu heating, cyclonic anomalies intensify over the Sea of Okhotsk and anticyclonic anomalies intensify over the northwest Pacific, affecting the western Pacific subtropical high. The results suggest that air sea interaction over the KOE must be considered to better understand the summer northwest Pacific climate.
  • Takeshi Horinouchi
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 92 6 519 - 541 2014年 [査読有り][通常論文]
     
    This study provides an overall understanding of the summertime synoptic variability of precipitation and moisture transport at mid-latitude from the eastern coastal region of China to the northwestern Pacific. Using satellite precipitation and reanalysis data, a clear relationship is found between upper tropospheric disturbances (Rossby waves), surface precipitation, and lower tropospheric humidity through July and August. The upper tropospheric disturbances are characterized by the undulation of the 1.5 PVU contours of potential vorticity (PV) on the 350 K isentropic surfaces. Case studies suggest that a precipitation band of several hundred kilometers wide and a thousand to several thousand kilometers long is formed very frequently on the equatorward and low-PV side of the northernmost 1.5 PVU contours, which meander together around 40 degrees N. Lower tropospheric specific humidity is also enhanced there, and it falls sharply to the north of these contours. The synoptic situations associated with it include, but are not limited to(2) a common situation in which moist convection is enhanced ahead of upper-level troughs. These results are confirmed by a composite analysis over the 12 summers from 2001. A novel method of analyzing the forcing of the quasi-geostrophic potential enstrophy, in which boundary contributions are incorporated, reveals that upper tropospheric disturbances in the area are propagated predominantly from the west along the Asian jet, and that they exert a significant forcing onto near-surface levels, while the upward forcing from near-surface levels to upper tropospheric disturbances is weak. A Q-vector analysis shows that the upwelling associated with the precipitation bands is forced predominantly by confluence. This process is frontogenetic, and surface fronts are often formed therein. The upwelling is enhanced by latent heating. The latitudinal extent of humid air masses is affected not only by this circulation but by low-level flows induced by upper-level disturbances in a cooperative manner.
  • Takeshi Horinouchi
    Journal of the Atmospheric Sciences 70 2 600 - 606 2013年02月 [査読有り][通常論文]
     
    The relationship between the interannual variations of the activity of convectively coupled equatorial waves and seasonal mean precipitation in the tropical western to central Pacific Ocean is investigated. It is found that the convectively coupled mixed Rossby-gravity (MRG) waves are highly and negatively correlated with the seasonal precipitation near the equator in boreal summer. It is suggested that theMRGwaves, which have convection centers off the equator, suppress the equatorial precipitation. The relation is insignificant in the other seasons, when the interannual variation of sea surface temperature near the equator is greater than in boreal summer. Also, a similar relation is not found in the eastern Pacific in any season. © 2013 American Meteorological Society.
  • Shigenori Otsuka, Seiya Nishizawa, Takeshi Horinouchi, Shigeo Yoden
    Journal of Disaster Research 8 1 48 - 56 2013年 [査読有り][通常論文]
     
    Gfdnavi is a web-based data and knowledge server program for geophysical fluid data that constructs databases, provides analysis and visualization tools, and shares knowledge documents. A new Gfdnavi user interface for analyzing and visualizing data on web browsers is developed to improve the user experience by providing seamless analysis and visualization operations, multiple diagram editing, a layer function, and so on. An experimental data handling system for ensemble numerical weather prediction data is constructed using Gfdnavi to address such issues as data processing and transfer between weather centers and decision makers in various sectors, including that of disaster management. Special tools to analyze and visualize ensemble numerical weather prediction data are implemented as user-defined Gfdnavi plug-ins. An interactive document that provides basic ideas of how to utilize probabilistic ensemble data information is written with the Gfdnavi knowledge documentation system, in which hyperlinks enable users to edit diagrams in the document.
  • Gfdnavi: A tool to analyze, visualize, and share meteorological data, and its application to the output of ensemble predictions
    S. Otsuka, S. Nisizawa, T. Horinouchi, S. Yoden
    Journal of Disaster Research 8 1 135 - 136 2013年 [査読有り][通常論文]
  • Tatsuya Terao, Takeshi Horinouchi
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 90 6 947 - 958 2012年12月 [査読有り][通常論文]
     
    The relation between the synoptic variability of low cloud amounts and the wave disturbances over the eastern tropical Pacific is studied using data from an atmospheric reanalysis (ERA-Interim) and the International Satellite Cloud Climatology Project (ISCCP) over 12 years (from 1990 to 2001). Here, low clouds are defined as those having the tops between 800 and 680 hPa. A significant correlation is found between the low cloud amount and the meridional wind over 3-7 day periods. Composite analyses show that mixed Rossby-gravity waves in the tropics and Rossby waves in mid-latitudes contribute to the synoptic variability of the low cloud amount. These waves induce the fluctuations of the low cloud amount independently, and the low cloud variability is explained as their superposition. Quantitative analyses suggest that these waves affect the low cloud amount through horizontal advection of clouds and the modulation of static stability.
  • Takeshi Horinouchi
    JOURNAL OF THE ATMOSPHERIC SCIENCES 69 3 891 - 907 2012年03月 [査読有り][通常論文]
     
    Aquaplanet simulations for a given sea surface temperature (SST) are conducted to elucidate possible roles of transient variability in the Hadley circulation and the intertropical convergence zone (ITCZ). Their roles are best illustrated with globally uniform SSTs. For such SSTs, an ITCZ and a Hadley circulation that are nearly equatorially symmetric emerge spontaneously. Their strength varies over a wide range from being faint to climatologically significant depending on a tunable parameter of the model's cumulus parameterization. In some cases asymmetric Hadley circulations formed along with long-lived tropical cyclones. The tunable parameter affects the transient variability of tropical precipitation. In the runs in which well-defined near-symmetric ITCZs formed, tropical precipitation exhibited clear signatures of convectively coupled equatorial waves. The waves can explain the concentration of precipitation to the equatorial region, which induces the Hadley circulation. Also, the meridional structures of simulated ITCZs are consistent with the distribution of convergence/divergence associated with dominant equatorial wave modes. Even when the pole equator temperature gradient is introduced, the dependence of the strength of the circulation to transient disturbances remains. Therefore, transient variability may have a broader impact on tropical climate and its numerical modeling than has been thought. The reason that a wide variety of circulation is possible when the SST gradient is weak is because the distribution of latent heating can be interactively adjusted while a circulation is formed. Angular momentum budget does not provide an effective thermodynamic constraint, since baroclinic instability redistributes the angular momentum.
  • M. Ishiwatari, E. Toyoda, Y. Morikawa, S. Takehiro, Y. Sasaki, S. Nishizawa, M. Odaka, N. Otobe, Y. O. Takahashi, K. Nakajima, T. Horinouchi, M. Shiotani, Y.-Y. Hayashi, Gtool development group
    Geosci. Model Dev. 5 2 449 - 455 2012年 [査読有り][通常論文]
  • M. Nakamura, T. Imamura, N. Ishii, T. Abe, T. Satoh, M. Suzuki, M. Ueno, A. Yamazaki, N. Iwagami, S. Watanabe, M. Taguchi, T. Fukuhara, Y. Takahashi, M. Yamada, N. Hoshino, S. Ohtsuki, K. Uemizu, G. L. Hashimoto, M. Takagi, Y. Matsuda, K. Ogohara, N. Sato, Y. Kasaba, T. Kouyama, N. Hirata, R. Nakamura, Y. Yamamoto, N. Okada, T. Horinouchi, M. Yamamoto, Y. Hayashi
    EARTH PLANETS AND SPACE 63 5 443 - 457 2011年 [査読有り][通常論文]
     
    The Akatsuki spacecraft of Japan was launched on May 21, 2010. The spacecraft planned to enter a Venus-encircling near-equatorial orbit in December 7, 2010; however, the Venus orbit insertion maneuver has failed, and at present the spacecraft is orbiting the Sun. There is a possibility of conducting an orbit insertion maneuver again several years later. The main goal of the mission is to understand the Venusian atmospheric dynamics and cloud physics, with the explorations of the ground surface and the interplanetary dust also being the themes. The angular motion of the spacecraft is roughly synchronized with the zonal flow near the cloud base for roughly 20 hours centered at the apoapsis. Seen from this portion of the orbit, cloud features below the spacecraft continue to be observed over 20 hours, and thus the precise determination of atmospheric motions is possible. The onboard science instruments sense multiple height levels of the atmosphere to model the three-dimensional structure and dynamics. The lower clouds, the lower atmosphere and the surface are imaged by utilizing near-infrared windows. The cloud top structure is mapped by using scattered ultraviolet radiation and thermal infrared radiation. Lightning discharge is searched for by high speed sampling of lightning flashes. Night airglow is observed at visible wavelengths. Radio occultation complements the imaging observations principally by determining the vertical temperature structure.
  • Takeshi Horinouchi, Seiya Nishizawa, Chiemi Watanabe, Akinori Tomobayashi, Shigenori Otsuka, Tsuyoshi Koshiro, Yoshi-Yuki Hayashi
    DATABASE SYSTEMS FOR ADVANCED APPLICATIONS 6193 93 - + 2010年 [査読有り][通常論文]
     
    In recent years, many data centers and research groups provide data on geophysical fluids such as the atmosphere and oceans through the Internet along with on-line visualization. However, their services are not available once data files are downloaded. This paper presents open-source software named Gfdnavi developed to reduce the limitation and to support data handling beyond initial "quick-looks". Gfdnavi extracts metadata from scientific data and stores them in a database. They can be accessed with web browsers for search, analysis, and visualization. It supports a wide range of usage such as public data services, group data management, and desktop use. As its unique feature, Gfdnavi supports writing and archiving documents based on knowledge obtained through-data analysis. The documents are linked with the original data and analysis/visualization procedures. It has a wide variety of applications such as interdisciplinary- and collaborative-study support, a realization of falsifiability, and educational use.
  • Seiya Nishizawa, Takeshi Horinouchi, Chiemi Watanabe, Yuka Isamoto, Akinori Tomobayashi, Shigenori Otsuka
    DATABASE SYSTEMS FOR ADVANCED APPLICATIONS 6193 105 - + 2010年 [査読有り][通常論文]
     
    In recent years, increasing amounts of scientific data on geophysical and environmental fluids, e.g., in the atmosphere and oceans, are being available. Further, there is increasing demand for web-based data services. Several browser-based data servers, on which geophysical-fluid data can be analyzed and visualized, have been developed. However, they are suitable only for initial "quick-looks" and not for subsequent research processes. As a solution, we developed data server software named Gfdnavi. One of its important features is that it provides extensive support for programming (scripting). With Gfdnavi, users can easily switch between operations using a web browser and operations using scripts or command lines. This paper describes its network features: web services, which is an important part of Gfdnavi's programmability, and the functionality to search across multiple Gfdnavi servers. To develop the web services, we adopted the REST architecture. We also developed a client library to ensure access to web services in the programming language Ruby. Using this library, data can be analyzed and visualized on either the server side or client side. It also enables data handling on multiple servers. Search across multiple web servers is made possible by a simple peer-to-peer network with a central server, with the peer-to-peer communication based on web services.
  • Takeshi Horinouchi, Toshitaka Tsuda
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 114 2009年08月 [査読有り][通常論文]
     
    A number of studies have investigated atmospheric gravity waves (GWs) using temperature profiles from GPS radio occultation (RO). This study is the first to report the horizontal structures of GWs obtained directly by using multiple profiles based on the GPS RO data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/FORMOSAT-3 mission. It was found that the horizontal locations of profiles obtained from successive passages of multiple COSMIC satellites were frequently aligned quasi-linearly over distances of around 1500-5000 km. Therefore, almost instantaneous (within 1 h) snapshots of vertical-horizontal cross sections of atmospheric temperature could be obtained. Clear GW features over multiple occultations were identified in many of the cross sections. It was indicated from a statistical analysis that horizontal wavelengths of GWs in the winter (here northern) hemisphere were generally smaller than those in the equatorial region or in the other hemisphere. A positive skewness was found in the probability distribution of the GW amplitude in middle to high latitudes, while the distribution was not skewed in low latitudes. GWs in the northern midlatitudes were studied further. In the zonal direction, both eastward and westward propagations relative to background winds were identified. The GW amplitude had a negative correlation with zonal wind shear. In the meridional direction, northward propagation was dominant, indicating that the dominant source region of meridionally propagating GWs was in the subtropics.
  • Takeshi Horinouchi, Toshitaka Tsuda
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 114 2009年08月 [査読有り][通常論文]
     
    A number of studies have investigated atmospheric gravity waves (GWs) using temperature profiles from GPS radio occultation (RO). This study is the first to report the horizontal structures of GWs obtained directly by using multiple profiles based on the GPS RO data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/FORMOSAT-3 mission. It was found that the horizontal locations of profiles obtained from successive passages of multiple COSMIC satellites were frequently aligned quasi-linearly over distances of around 1500-5000 km. Therefore, almost instantaneous (within 1 h) snapshots of vertical-horizontal cross sections of atmospheric temperature could be obtained. Clear GW features over multiple occultations were identified in many of the cross sections. It was indicated from a statistical analysis that horizontal wavelengths of GWs in the winter (here northern) hemisphere were generally smaller than those in the equatorial region or in the other hemisphere. A positive skewness was found in the probability distribution of the GW amplitude in middle to high latitudes, while the distribution was not skewed in low latitudes. GWs in the northern midlatitudes were studied further. In the zonal direction, both eastward and westward propagations relative to background winds were identified. The GW amplitude had a negative correlation with zonal wind shear. In the meridional direction, northward propagation was dominant, indicating that the dominant source region of meridionally propagating GWs was in the subtropics.
  • R. F. Garcia, P. Drossart, G. Piccioni, M. López-Valverde, G. Occhipinti
    Journal of Geophysical Research 114 2009年03月17日 [査読有り]
  • Takeshi Horinouchi, Toshitaka Tsuda
    Journal of Geophysical Research Atmospheres 114 16 2009年 [査読有り][通常論文]
     
    [1] A number of studies have investigated atmospheric gravity waves (GWs) using temperature profiles from GPS radio occultation (RO). This study is the first to report the horizontal structures of GWs obtained directly by using multiple profiles based on the GPS RO data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC)/FORMOSAT-3 mission. It was found that the horizontal locations of profiles obtained from successive passages of multiple COSMIC satellites were frequently aligned quasi-linearly over distances of around 1500-5000 km. Therefore, almost instantaneous (within 1 h) snapshots of vertical-horizontal cross sections of atmospheric temperature could be obtained. Clear GW features over multiple occultations were identified in many of the cross sections. It was indicated from a statistical analysis that horizontal wavelengths of GWs in the winter (here northern) hemisphere were generally smaller than those in the equatorial region or in the other hemisphere. A positive skewness was found in the probability distribution of the GW amplitude in middle to high latitudes, while the distribution was not skewed in low latitudes. GWs in the northern midlatitudes were studied further. In the zonal direction, both eastward and westward propagations relative to background winds were identified. The GW amplitude had a negative correlation with zonal wind shear. In the meridional direction, northward propagation was dominant, indicating that the dominant source region of meridionally propagating GWs was in the subtropics. Copyright 2009 by the American Geophysical Union.
  • Takeshi Horinouchi
    GEOPHYSICAL RESEARCH LETTERS 35 17 2008年09月 [査読有り][通常論文]
     
    Convectively generated atmospheric gravity waves that propagate into the equatorial stratosphere were investigated using a cloud resolving model. Numerical simulations were conducted to study wave generation during convectively inactive and active phases in a cycle of the Madden-Julian oscillation, which occurred during an observational campaign conducted in Sumatra. Greater convective activity during the active phase caused stronger disturbances in the troposphere at relatively low phase speeds less than about 20m/s than the inactive phase. However, the contrast was weaker at higher phase speeds. Furthermore, the vertical structure of convective forcing in the inactive phase was more suitable to excite waves with wavelength longer than twice the depth of convection. Owing to the combination of these factors, upward gravity wave propagation was significantly enhanced during the inactive phase. This study demonstrates the necessity to study convection spectrally to investigate possible links between intraseasonal variabilities in the troposphere and the middle atmosphere.
  • S. Sridharan, T. Tsuda, T. Nakamura, T. Horinouchi
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 86 1 43 - 55 2008年02月 [査読有り][通常論文]
     
    An eastward propagating Kelvin wave of period near 7 days is observed in the radiosonde winds and temperature in the upper troposphere and lower stratosphere (UTLS) region and a wave of similar periodicity is observed simultaneously in the Mesosphere and Lower Thermosphere (MLT) winds acquired by MF radar at Pameungpeuk (7.5 degrees S, 107.5 degrees E) during the first Coupling Processes in the Equatorial Atmosphere (CPEA-1) Campaign (April 10-May 9, 2004). The horizontal and vertical characteristics of these waves are investigated using winds and temperature data acquired by TIDI (TIMED Doppler Interferometer) and Sounding of Atmosphere using Broadband Emission Radiometry (SABER) instruments respectively on TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite and European Centre for Medium-Range Weather Forecasts (ECMWF) winds and temperature. The wave observed in the MLT region has a dominant period of approximately 6.5 days and is found to propagate westward with zonal wave number 1. The horizontal structures of the wave in winds and the temperature indicate that the wave is of gravest symmetric wave number 1 Rossby wave. The downward phase propagation from the MLT region to tropopause indicates that the wave may have a source in the troposphere. The Kelvin wave observed in the UTLS region has zonal wave number 3. However, this wave becomes damped above 23 km, where the above mentioned westward propagating wave begins to amplify. During the observation period, the OLR distribution in the tropics shows similar periodicities, propagating eastward with zonal wave number 3 and westward with zonal wave number 1. These observations suggest that tropical convective heating may be a common source for these waves.
  • Eriko Touma, Satomi Hara, Mari Kurumi, Yuri Shirakawa, Chisato Ishikawa, Masami Takata, Takeshi Horinouchi, Kazuki Joe
    GRAPP 2008: PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON COMPUTER GRAPHICS THEORY AND APPLICATIONS 409 - 414 2008年 [査読有り][通常論文]
     
    Recent improvement of high-end GPUs has made it possible to perform real-time 3D visualization such as volume rendering and 3D contour plot for scientific data locally. A web browser based remote 3D visualization by visualization servers is attractive, but data transfer overhead prevents from performing interactive operations. We propose an interactive remote 3D visualization model by live streaming for geophysical fluids research. In this model, we use live streaming flash media for the web browser based operations keeping minimum quality of data analysis and minimum bit rate for live streaming of flash media. Preliminary experiments with a prototype system validate the effectiveness of our proposing model.
  • Masayuki K. Yamamoto, Noriyuki Nishi, Takeshi Horinouchi, Masanori Niwano, Shoichiro Fukao
    RADIO SCIENCE 42 3 2007年05月 [査読有り][通常論文]
     
    [1] Features of upper tropospheric vertical wind ( W) over Sumatra, Indonesia, are presented using data observed by a VHF wind profiler installed at West Sumatra (0.2 degrees S, 100.32 degrees E). During 5 - 9 May 2004, W from the middle to upper troposphere ( 8 - 14 km) changed in accordance with the cumulus activity over Sumatra. During 5 - 6 May, 3-hourly averaged W continuously showed upward motions up to 0.09 m s(-1). The upward motions were observed in the vicinity of deep convective events, which were continuously seen over Sumatra within a synoptic-scale convectively active envelope. After 7 May, when cumulus activity was suppressed over Sumatra, 3-hourly averaged upward motions of greater than 0.05 m s(-1) almost disappeared. During 5 - 6 May, downward motions up to similar to 0.11 m s(-1) were observed above 14 km, while upward motions were observed below 14 km. Estimation of W by the European Centre for Medium-Range Weather Forecasts operational analysis have revealed that a major part of observed downward motions above 14 km is explained by the leeward ( southwestward) wind and leeward downward tilt of isentropes that existed over western Sumatra. The observed downward motions above 14 km during 5 - 6 May suggest that downward motions caused by leeward downward tilt of isentropes can be produced in the vicinity of the convectively active region, and leeward downward tilt of isentropes can suppress an upward transport of air mass into the tropical tropopause layer (TTL) by producing downward motions in the TTL.
  • K. Shiokawa, S. Suzuki, Y. Otsuka, T. Ogawa, T. Nakamura, T. Horinouchi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 112 D7 2007年04月 [査読有り][通常論文]
     
    [1] We report an intense gravity wave event observed at Shigaraki, Japan, at 1500 - 2000 UT (0000 - 0500 LT) on 22 December 2001 using a Fabry-Perot interferometer, which measures the Doppler shift of nocturnal airglow emission at a wavelength of 557.7 nm (emission altitude: 90 - 100 km). The wave had a period of 1.5 hours and a peak-to-peak amplitude of 68 m/s in the horizontal wind velocity. The hodograph of the east-west and north-south wind oscillations showed a polarization direction of the wave of ENE-WSW. An all-sky airglow imager at Shigaraki also recorded a similar southwestward moving wave with a period of similar to 1.5 hours and a velocity of 146 m/s in the 557.7-nm airglow images. The horizontal wavelength was estimated to be 790 km from the images. These facts indicate that the wave was generated in the northeast of Japan, where a well-developed low-pressure cell (968 hPa) and a distortion of the jet stream were observed in the troposphere. However, the large horizontal wavelength, the fast phase velocity, and the possible source location apart from the exit of the jet streak are different from those predicted from previous numerical simulations.
  • 地球流体データベース・解析・可視化のための新しいサーバ兼デスクトップツール Gfdnavi の開発
    堀之内 武, 西澤 誠也, 渡辺 知恵美, 森川 靖大, 神代 剛, 石渡 正樹, 林 祥介, 塩谷雅人
    電子情報通信学会第18回データ工学ワークショップ(DEWS2007)論文集 E1-8 (pp.8) 2007年 [査読有り][通常論文]
  • RDoc を用いた数値モデルのドキュメント生成
    森川 靖大, 石渡 正樹, 堀之内 武, 小高 正嗣, 林 祥介
    天気 54, 185-190 2007年 [査読無し][通常論文]
  • HY Chun, IS Song, T Horinouchi
    JOURNAL OF THE ATMOSPHERIC SCIENCES 62 11 4113 - 4120 2005年11月 [査読有り][通常論文]
     
    The momentum flux of convectively forced internal gravity waves is calculated using explicitly resolved model-simulated gravity wave data. The momentum flux in a control simulation with nonlinearity and cloud microphysical processes is compared with that in quasi-linear dry simulations with either diabatic forcing or nonlinear forcing. It is found that the momentum flux induced by either of these two sources is significantly different from each other and also from the momentum flux in the control simulation. This is because the spectral distribution and magnitude of each wave source are significantly different and the cancellation of the momentum flux by cross-correlation terms between the two sources cannot be included in the momentum flux by a single source. This suggests that a parameterization of convectively forced gravity waves must take into account nonlinear forcing as well as diabatic forcing in order to qualitatively and quantitatively represent the reference-level momentum flux spectrum.
  • T Yokoyama, T Horinouchi, M Yamamoto, S Fukao
    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 109 A12 2004年12月 [査読有り][通常論文]
     
    We have studied coupling between the neutral atmosphere and the ionospheric E region in the midlatitude by combining two numerical simulation models. Atmospheric gravity waves generated in the troposphere propagate through the stratosphere and the mesosphere and can reach the lower thermosphere. When a zonal wind shear that can accumulate a sporadic-E (E-s) layer (eastward below and westward above) is applied, the accumulated E-s layer is strongly modulated by the gravity waves, and polarization electric field due to the modulated E-s layer produces wave-like patterns of plasma density in the upper E region. Since the eastward wind below the shear node filters out gravity waves with eastward phase velocity, those with westward phase velocity are dominant where the E-s layer is accumulated. Because of the angle between phase front of gravity waves and the geomagnetic field line, gravity waves with southward phase velocity is more effective to generate polarization electric field than those with northward phase velocity. Since gravity waves with southwestward phase velocity have phase fronts aligned from northwest to southeast, polarization electric field also has the similar structure. This mechanism can explain the spatial structure of quasi-periodic (QP) echoes associated with plasma irregularities in the midlatitude E region which often shows northwest-southeast alignment.
  • T Imamura, T Horinouchi, TJ Dunkerton
    JOURNAL OF THE ATMOSPHERIC SCIENCES 61 15 1966 - 1975 2004年08月 [査読有り][通常論文]
     
    A modified, equatorial Kelvin wave solution is obtained in the presence of the zonal-mean meridional circulation. The modified Kelvin wave solution, which is obtained via a perturbation expansion of the linearized, primitive equations on an equatorial beta plane, possesses a nonzero meridional wind component. This meridional wind component is absent when the background flow is at rest. The combination of the meridional and zonal winds induces a meridional flux of zonal momentum in the upstream direction of the background north - south flow. This flux is divergent in latitude and produces a nonzero wave-induced force even though the waves are linear, steady, and conservative. It is shown that, although such a force violates the traditional nonacceleration theorem in which the mean meridional circulation is negligible at leading order, the result is in accord with a more general nonacceleration theorem obtained from the exact generalized Lagrangian-mean theory in which the mean meridional circulation is nonzero. The meridional circulation, in effect, attempts to advect wave pseudomomentum off the equator, resulting in a nonzero acceleration in the Eulerian reference frame. The meridional flux of momentum for any equatorially trapped mode is derived from the generalized Lagrangian-mean theory. Those modes with eastward ( westward) intrinsic phase velocity transport eastward ( westward) zonal momentum in the upstream direction of the background meridional flow in the neighborhood of the equator. It is also shown that the vertical flux of zonal momentum is not constant with altitude in a steady vertical flow since diabatic heating/cooling is needed to sustain the vertical wind. Implications of the results for the terrestrial and Venusian atmospheres are discussed.
  • T Horinouchi
    JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 66 6-9 755 - 767 2004年04月 [査読有り][通常論文]
     
    A number of numerical simulations are conducted by using a vertically extended mesoscale meteorological model to study the breaking of atmospheric gravity waves generated by cumulus convection and the airglow modulation in the upper mesosphere induced by the breaking. It is found that a simulation with horizontal and vertical grid spacings of 1.5 and 0.5 km, as in Horinouchi et al. (Geophys. Res. Lett. 29(21) (2002) 2007), can crudely simulate the breaking, but the dynamics of the breaking and airglow modulation is better elucidated with a higher resolution. Sensitivity of the results to subgrid-scale turbulence closures is also examined. From the simulations, the 015577 atomic oxygen airglow is estimated with an approximate method proposed in this study. It is found, as has been expected, that the disturbances associated with the wave breaking modulate the airglow to create the so-called "ripple"-type patterns consisting of stripes with a spacing of about 10 km, which are frequently found in ground-based airglow imaging. Using a high-resolution simulation, it is found that in some breaking cases the initial instability disturbance develops into shear instability creating billows that induce a conspicuous airglow ripple, although their stripe structure is disturbed. In such a case, conventional vortex diagnosis suggests the dominance of well-developed turbulence. The result indicates that a significant airglow modulation can develop at a late stage of instability that has not been considered to cause a coherent airglow modulation. (C) 2003 Elsevier Ltd. All rights reserved.
  • T. Yokoyama, T. Horinouchi, M. Yamamoto, S. Fukao
    Journal of Geophysical Research: Space Physics 109 12 2004年 [査読有り][通常論文]
     
    [1] We have studied coupling between the neutral atmosphere and the ionospheric E region in the midlatitude by combining two numerical simulation models. Atmospheric gravity waves generated in the troposphere propagate through the stratosphere and the mesosphere and can reach the lower thermosphere. When a zonal wind shear that can accumulate a sporadic-E (Es) layer (eastward below and westward above) is applied, the accumulated Es layer is strongly modulated by the gravity waves, and polarization electric field due to the modulated Es layer produces wave-like patterns of plasma density in the upper E region. Since the eastward wind below the shear node filters out gravity waves with eastward phase velocity, those with westward phase velocity are dominant where the Es layer is accumulated. Because of the angle between phase front of gravity waves and the geomagnetic field line, gravity waves with southward phase velocity is more effective to generate polarization electric field than those with northward phase velocity. Since gravity waves with southwestward phase velocity have phase fronts aligned from northwest to southeast, polarization electric field also has the similar structure. This mechanism can explain the spatial structure of quasi-periodic (QP) echoes associated with plasma irregularities in the midlatitude E region which often shows northwest-southeast alignment. Copyright 2004 by the American Geophysical Union.
  • T Horinouchi, S Pawson, K Shibata, U Langematz, E Manzini, MA Giorgetta, F Sassi, RJ Wilson, K Hamilton, J de Grandpre, AA Scaife
    JOURNAL OF THE ATMOSPHERIC SCIENCES 60 22 2765 - 2782 2003年11月 [査読有り][通常論文]
     
    It is recognized that the resolved tropical wave spectrum can vary considerably among general circulation models (GCMs) and that these differences can have an important impact on the simulated climate. A comprehensive comparison of low-latitude waves is presented for the December-January-February period using high-frequency data from nine GCMs participating in the GCM Reality Intercomparison Project for Stratospheric Processes and Their Role in Climate (GRIPS; SPARC). Quantitative measures of the wavenumber-frequency structure of resolved waves and their impacts on the zonal mean circulation are given. Space-time spectral analysis reveals that the wave spectrum throughout the middle atmosphere is linked to the variability of convective precipitation, which is determined by the parameterized convection. The variability of the precipitation spectrum differs by more than an order of magnitude among the models, with additional changes in the spectral distribution (especially the frequency). These differences can be explained primarily by the choice of different cumulus parameterizations: quasi-equilibrium mass-flux schemes tend to produce small variability, while the moist-convective adjustment scheme is the most active. Comparison with observational estimates of precipitation variability suggests that the model values are scattered around the observational estimates. Among the models, only those that produce the largest precipitation variability can reproduce the equatorial quasi-biennial oscillation (QBO). This implies that in the real atmosphere, the forcing from the waves, which are resolvable with the typical resolutions of present-day GCMs, is insufficient to drive the QBO. Parameterized cumulus convection also impacts the nonmigrating tides in the equatorial region. In most of the models, momentum transport by diurnal nonmigrating tides in the mesosphere is comparable to or larger than that by planetary-scale Kelvin waves, being more significant than has been thought. It is shown that the westerly accelerations in the equatorial semi-annual oscillation in the models examined are driven mainly by gravity waves with periods shorter than 3 days, with some contribution from parameterized gravity waves, and that the contribution from the wavenumber-1 Kelvin waves is negligible. These results provide a state-of-the-art assessment of the links between convective parameterizations and middle-atmospheric waves in present-day middle-atmosphere climate models.
  • M Fujiwara, M Shiotani, F Hasebe, H Vomel, SJ Oltmans, PW Ruppert, T Horinouchi, T Tsuda
    JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 20 11 1534 - 1542 2003年11月 [査読有り][通常論文]
     
    The "Snow White'' hygrometer is a low-cost, chilled-mirror hygrometer for radiosonde applications provided by a Swiss company, Meteolabor AG. A total of 54 Snow White soundings were conducted at five tropical stations in different seasons in 2000-01. All soundings were made with Vaisala RS80 radiosondes equipped either with the A-Humicap (22 soundings) or H-Humicap (32) relative humidity (RH) sensor. Comparisons of the RH with respect to liquid water between the Snow White and the different RS80 Humicap sensors are made. The Snow White measurements show reasonable agreement with the H-Humicap measurements from the surface up to similar to12 km (above -50degreesC air temperature), the region where the H-Humicap sensor can be considered reliable. Above 12 km, the H-Humicap sensor tends to miss small vertical-scale structures in RH due to the time lag error, but on average both instruments show no significant difference up to 14 km(-65degreesC). The comparison between the Snow White and A-Humicap sensors shows the known A-Humicap dry bias error at low temperatures and second dry bias error in the wet lower troposphere. The latter error [(A-Humicap RH)similar or equal to0.93 (Snow White RH) above 50% RH] may be a common problem for the recent A-Humicap sensors. These intercomparisons confirm the validity of the Snow White measurements at least up to the tropical upper troposphere and above 3%-6% RH.
  • MK Yamamoto, M Oyamatsu, T Horinouchi, H Hashiguchi, S Fukao
    GEOPHYSICAL RESEARCH LETTERS 30 21 2003年11月 [査読有り][通常論文]
     
    The Equatorial Atmosphere Radar ( EAR) is located at the equator (0.20degreesS, 100.32degreesE) in West Sumatra, Indonesia. The capability of the EAR to observe short-term variations of the tropopause altitude is shown. Near the tropopause, the EAR receives strong echoes caused by the rapid increase of hydrostatic stability with altitude. By applying this characteristic, the radar tropopause (RT) was determined. The RT agreed well with both the lapse-rate tropopause (LRT) and the cold-point tropopause (CPT) in altitude with a time resolution of 3 hours. The power spectrum of the RT altitude from 1 July to 18 December, 2001 showed a clear 1-day peak. The amplitude of its diurnal cycle as revealed in composites is as small as similar to0.1 km. Nevertheless, the RT was able to reproduce the diurnal cycle in the LRT and the CPT well, which indicates that the EAR can observe short-term variations of the tropical tropopause.
  • SC Sherwood, T Horinouchi, HA Zeleznik
    JOURNAL OF THE ATMOSPHERIC SCIENCES 60 15 1847 - 1856 2003年08月 [査読有り][通常論文]
     
    Observed temperature trends and interannual variations near the tropical tropopause suggest that temperatures up to the cold point are controlled by the troposphere, but some models indicate otherwise. Here, previous investigations of thermal anomalies and heating profiles associated with tropical convective outbreak are extended, by examining behavior near the tropopause. Observations show that active convective systems are locally associated with warm anomalies in the upper troposphere but cold anomalies in the lower troposphere and near the tropopause. Time-dependent solutions of Laplace's equations demonstrate that the cold anomaly below 100 hPa can be, at least partly, accounted for by adiabatic lofting associated with a transient heating pulse at lower levels. However, detailed examination of the cold-point tropopause in the data reveals that it moves against the lofting, downward toward higher pressure and colder potential temperatures, in response to convection. These variations qualitatively agree with longitudinal and ENSO-related variations in tropopause height and temperature reported in the literature, though seen here on hourly timescales. From this, local mesoscale diabatic cooling of several degrees kelvin per day close to the tropopause during active convection is inferred. This exceeds the likely contribution from cloud-top radiative cooling, suggesting a role for convective turbulence in refrigerating the tropopause.
  • MK Yamamoto, M Fujiwara, T Horinouchi, H Hashiguchi, S Fukao
    GEOPHYSICAL RESEARCH LETTERS 30 13 2003年07月 [査読有り][通常論文]
  • MK Yamamoto, M Fujiwara, T Horinouchi, H Hashiguchi, S Fukao
    GEOPHYSICAL RESEARCH LETTERS 30 9 2003年05月 [査読有り][通常論文]
     
    [1] In November 2001, the Equatorial Atmosphere Radar (0.20degreesS, 100.32degreesE) observed a continuous strong eastward wind shear (10-50 m s(-1) km(-1)), westward wind (2-27 m s(-1)), and the radar echo layer tilted downward to the west in the region 0-1 km above the tropopause. During the same period, the Richardson number calculated with hourly-averaged horizontal wind and radiosonde temperature data was almost continuously <0.5 and sometimes <0.25, which seems to indicate that the Kelvin-Helmholtz instability (KHI) frequently occurs in that region. The existence of the tilted radar echo layer can be explained by KHI billows. A spurious updraft caused by the KHI-induced tilted echo layer and by the strong westward wind was also observed in the region.
  • M Fujiwara, MK Yamamoto, H Hashiguchi, T Horinouchi, S Fukao
    GEOPHYSICAL RESEARCH LETTERS 30 4 2003年02月 [査読有り][通常論文]
     
    The Equatorial Atmosphere Radar ( EAR) installed in Sumatra Island, Indonesia, observed significant enhancement of turbulence in the tropopause region, 15-17 km, intermittently for similar to5 days in November 2001. The turbulence intensity was estimated with the spectral width of the radar echo power spectrum, and the turbulence during the period was a factor of up to similar to5 larger in kinetic energy than that in other periods. Further analyses confirm that the enhanced turbulence was convectively generated in the breaking phase of an equatorial Kelvin wave. Between July and December 2001, we observed at least three more prominent cases of the turbulence generation by breaking Kelvin waves in the tropopause region.
  • T Horinouchi, T Nakamura, J Kosaka
    GEOPHYSICAL RESEARCH LETTERS 29 21 2002年11月 [査読有り][通常論文]
     
    A three-dimensional simulation was conducted with a cloud-resolving model to investigate mesoscale gravity waves generated by cumulus convection that propagate to the mesospheric and lower thermospheric (MLT) region. It is found that both individual convective turrets and mesoscale convective systems excite gravity waves, resulting in a broad scale distribution. Waves excited by the former have conically shaped phase surfaces as previously reported and are conspicuous up to around the stratopause. Waves excited by the latter dominate in the MLT region. Frequent wave breaking is found above 85 km, where convective instability is found typically in the initial stage, leading to unstable shear with billows resembling the ripple-type structures observed frequently in airglow imaging.
  • TW Hadi, T Horinouchi, T Tsuda, H Hashiguchi, S Fukao
    MONTHLY WEATHER REVIEW 130 9 2153 - 2166 2002年09月 [査読有り][通常論文]
     
    Characteristics of sea-breeze circulation over the tropical site of Jakarta, Indonesia, have been documented based on analyses of satellite images and data from long-term L-band boundary layer radar measurements carried out at Serpong (6.4degreesS, 106.7degreesE). Inspection of satellite imagery reveals that a sea-breeze front develops well along the northern coastal plain of West Java and propagates inland until its structure is deformed over complex topography. It is found that the sea-breeze signal detected by the boundary layer radar is most well defined during the dry season months of July-October. In all of these months, radar observations indicate a late afternoon intensification of sea-breeze flow in the 0.5-0.8-km height range between 1700 and 1800 LT, which is not elucidated upon by surface measurements. The effect of weather conditions on the sea-breeze pattern is investigated by using a cloudiness index derived from data of incoming solar radiation. The results show that sea-breeze intrusion over the radar site occurs earlier during more cloudy days, whereas the intensity of sea-breeze circulation weakens accordingly. In the rainy season months of January and February, diurnal wind variation is characterized by daytime onshore flow enhancement, which is not likely attributed to sea-breeze circulation.
  • T Horinouchi
    JOURNAL OF THE ATMOSPHERIC SCIENCES 59 16 2428 - 2437 2002年08月 [査読有り][通常論文]
     
    Satellite-derived brightness temperature has been used to estimate tropical precipitation. Ricciardulli and Garcia applied it to quantify forcing of atmospheric waves that are excited by tropical cumulus convection and propagate into the middle atmosphere. Because of the broad coverage of the satellite data, this method provides exclusively dense information on wave forcing and is especially valuable for middle-atmosphere modeling. However, the validity of the method has not been investigated, which is done in this study using radar-derived precipitation during the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) field experiment. The method is shown to overestimate the variance of precipitation so that the wave forcing derived with it is too strong. The overestimation is most severe at coarse resolution, reaching nearly an order of magnitude at a grid scale of 2degrees, which is comparable to typical resolutions of current global climate models. Although the comparison was made using data from a limited region in the western Pacific, it is suggested that the method overestimates wave forcing globally. The probability distribution of the mean radar precipitation on the meso-beta scale fits well to the gamma distribution, while that for the satellite-derived precipitation does not. The latter shows a high probability of extreme grid mean precipitation, and this contributes to the overestimation. The frequency spectra of radar and satellite precipitation showed some similarity in shape, but differences are evident at subdiurnal frequencies. In addition to the satellite method, the Geostationary Operational Environmental Satellite (GOES) Precipitation Index (GPI) is also investigated. GPI shows a similar, but better, performance to estimate wave forcing.
  • MP Baldwin, LJ Gray, TJ Dunkerton, K Hamilton, PH Haynes, WJ Randel, Holton, JR, MJ Alexander, Hirota, I, T Horinouchi, DBA Jones, JS Kinnersley, C Marquardt, K Sato, M Takahashi
    REVIEWS OF GEOPHYSICS 39 2 179 - 229 2001年05月 [査読有り][通常論文]
     
    The quasi-biennial oscillation (QBO) dominates the variability of the equatorial stratosphere (similar to 16-50 km) and is easily seen as downward propagating easterly and westerly wind regimes, with a variable period averaging approximately 28 months. From a fluid dynamical perspective, the QBO is a fascinating example of a coherent, oscillating mean flow that is driven by propagating waves with periods unrelated to that of the resulting oscillation, Although the QBO is a tropical phenomenon, it affects the stratospheric flow from pole to pole by modulating the effects of extratropical waves. Indeed, study of the QBO is inseparable from the study of atmospheric wave motions that drive it and are modulated by it. The QBO affects variability in the mesosphere near 85 km by selectively filtering waves that propagate upward through the equatorial stratosphere, and may also affect the strength of Atlantic hurricanes. The effects of the QBO are not confined to atmospheric dynamics. Chemical constituents, such as ozone, water vapor, and methane, are affected by circulation changes induced by the QBO. There are also substantial QBO signals in many of the shorter-lived chemical constituents. Through modulation of extratropical wave propagation, the QBO has an effect on the breakdown of the wintertime stratospheric polar vortices and the severity of high-latitude ozone depletion. The polar vortex in the stratosphere affects surface weather patterns, providing a mechanism for the QBO to have an effect at the Earth's surface. As more data sources (e.g., wind and temperature measurements from both ground-based systems and satellites) become available, the effects of the QBO can be more precisely assessed. This review covers the current state of knowledge of the tropical QBO, its extratropical dynamical effects, chemical constituent transport, and effects of the QBO in the troposphere (similar to0-16 km) and mesosphere (similar to 50-100 km). It is intended to provide a broad overview of the QBO and its effects to researchers outside the held, as well as a source of information and references for specialists. The history of research on the QBO is discussed only briefly, and the reader is referred to several historical review papers. The basic theory of the QBO is summarized, and tutorial references are provided.
  • T Horinouchi, F Sassi, BA Boville
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 105 D21 26579 - 26592 2000年11月 [査読有り][通常論文]
     
    Atmospheric transport between the tropics and the extratropics, in the lowest part of the stratosphere during Northern Hemisphere winter, is investigated. The role of synoptic-scale disturbances that propagate laterally into the tropics is examined using the middle atmosphere version of the National Center for Atmospheric Research Community Climate Model Version 3 general circulation model. In the lower stratosphere, synoptic-scale Rossby waves propagate vigorously from the northern (i.e., winter) extratropics through two "westerly ducts,'' where the westerly zonal mean winds near the equator are favorable to Rossby wave propagation. The waves break in the westerly ducts and modify the mean potential vorticity (PV) structure to connect subtropical and equatorial regions of sharp PV gradients. Frequent wave breaking and the wave-induced PV structure create distinct routes where transport occurs vigorously between the tropics and the northern extratropics. Interhemispheric transport also occurs through regions associated with the westerly ducts. In the Southern (summer) Hemisphere lower stratosphere, synoptic-scale disturbances propagate mainly as "tongues" of PV elongated from extratropical disturbances. The transport between the tropics and the southern extratropics has a strong geographic preference but is dominated by the monsoon circulation, as was shown for the upper troposphere by Chen [1995]. PV tongues and other transient anomalies are of secondary importance.
  • AH Sobel, T Horinouchi
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 78 2 167 - 173 2000年04月 [査読有り][通常論文]
     
    The authors argue that certain aspects of the rotational, synoptic-scale disturbances of the wind field that are observed in ITCZ or monsoon trough regions can be understood by considering the linear response of a dry, initially resting atmosphere to a pulse of heating whose amplitude and spatial and temporal scales are characteristic of a large mesoscale convective system. The key points are that short Rossby waves have small intrinsic group and phase velocities, and that a heating pulse projects much more energy on the Rossby modes if it is located slightly off rather than on the equator. It follows that synoptic-scale Rossby waves, with characteristics broadly similar to those of observed disturbances, should be present in off-equatorial regions of persistent deep convection, since large mesoscale convective systems tend to develop in such regions.
  • T Horinouchi, S Yoden
    JOURNAL OF THE ATMOSPHERIC SCIENCES 55 4 502 - 526 1998年02月 [査読有り][通常論文]
     
    The interaction between convectively excited waves and the mean zonal wind in the equatorial lower stratosphere is investigated with a simplified general circulation model (GCM). The model has T42 truncation, and the vertical resolution is about 700 m in the stratosphere. Although it is an "aquaplanet" model with uniform sea surface temperature, cumulus convection in low latitudes has realistic hierarchical structures with reasonable space-time spectral distributions. The model produced an oscillation having quite similar features to the equatorial quasi-biennial oscillation (QBO), although the period is 400 days. Waves in the equatorial lower stratosphere of the model are excited mainly by the cumulus convection in low latitudes. The energy of these waves is a little larger than that observed in the real atmosphere. The dominant waves are gravity waves having an equivalent depth of about 200 m and those of 40-100 m. About half of the transport and deposition of zonal momentum contributing to the oscillation is accounted for by the gravest symmetric gravity modes: eastward momentum by Kelvin waves and westward momentum by n = 1 gravity waves. The momentum deposition is done over a wide range of zonal wavenumber (2-30), while about half of it is done over a period of 1-3 days. The deposition has rather continuous phase speed distributions and a considerable portion of it is provided by waves having critical levels. Since gravity waves with small intrinsic phase speeds have small vertical wavelengths, vertical grid spacings of 700 m or less appear to be required in the lower stratosphere for GCMs in order to simulate the QBO.
  • T Horinouchi, S Yoden
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 75 3 641 - 656 1997年06月 [査読有り][通常論文]
     
    Propagation of waves excited by localized episodic heating in the tropical troposphere and their effect on the middle atmosphere are investigated numerically with a global primitive-equation model in which a realistic radiation scheme for the middle atmosphere is incorporated. Equinoctial initial states with two opposite phases of the quasi-biennial oscillation (QBO) are used for comparison of the propagation and the effect of the waves. Time evolutions of the responses of the equinoctial initial states are not much different from the linear responses of a resting atmosphere obtained by Horinouchi and Yoden (1996). If the duration of the heating is small (less than about a day), Eliassen-Palm (EP) flux in the middle atmosphere is mainly due to gravity waves including Kelvin waves, while if the duration is large (more than about a day), it is mainly due to Kelvin waves, Rossby waves, and Rossby-gravity waves. In the westerly-shear phase of the QBO, westerly acceleration comparable to or a little smaller than that required by the QBO is obtained for wide range of heating parameters, while in the easterly-shear phase, realistic easterly acceleration cannot be obtained if the heating events have large time and horizontal scales (more than about a day and a few thousand kilometers). Gravity waves propagating into the low- and mid-latitude mesosphere are affected by the QBO. The difference in the divergence of the EP flux due to gravity waves may explain the observed quasi-biennial Variations in the low-and mid-latitude mesosphere. Excitation of the global normal mode 5-day wave is sensitive to the QBO phase. Since such a QBO modulation has not been observed, this result implies that the source of the 5-day wave in the real atmosphere is not or not only in the tropics, but a considerable portion of the wave is excited outside the tropics.
  • T Horinouchi, S Yoden
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 74 2 189 - 210 1996年04月 [査読有り][通常論文]
     
    Response of a resting spherical atmosphere to transient localized heating in the tropics is studied theoretically with linearized primitive equations. The method of separation of variables is used to solve the problem, and time-integrations of the full nonlinear equations are also done to assess the linearity of the response. The linearity of the response is good for some realistic values of the heating. The dominant responses are equatorially-trapped vertically propagating waves whose vertical scale matches that of the heating and global normal (or free) modes. In the middle atmosphere, the equatorially trapped waves respond effectively if the angular frequency is the order of 10 x [damping rate]. If the frequency is greater than this order, the response is suppressed in a stochastic sense; while if the frequency is less than this order, it is suppressed by the damping. Spatial pattern of the response is obtained for a realization of idealized stochastic heating: with a Gaussian form in space and time. For the heating, of which the time scale is a few days or longer, horizontal cross sections of the response show the ''Gill pattern'' at the beginning and then the response disperses zonally in low latitudes. For short-lived heating, on the other hand, the gravity wave response expands concentrically at the beginning and then the response spreads zonally in low latitudes. Energy and momentum spectra to various kinds of wave are calculated for the stochastic heating. As the time scale of the heating events decreases, gravity-wave responses increase relatively to Rossby-wave responses. As the zonal scale of the heating events decreases, on the other hand: Rossby-wave responses slightly increase relatively to the gravity-wave responses. Heating just on the equator is less effective to excite Rossby waves than that off the equator. Energy and momentum of these vertically propagating waves are of comparable orders to those of the real atmosphere if the heating has an appropriate spectrum with a realistic amount comparable to the total latent heat release in the tropics; and so does the energy of global normal modes. Wave energy propagation into the middle atmosphere has to be taken into account even for the calculation of the transient response in the troposphere if the dominant frequency is larger than the damping rate.
  • T Horinouchi, S Yoden
    TENTH CONFERENCE ON ATMOSPHERIC AND OCEANIC WAVES AND STABILITY 230 - 231 1995年 [査読有り][通常論文]
  • M SHIOTANI, T HORINOUCHI
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 71 1 175 - 182 1993年02月 [査読有り][通常論文]
     
    This note presents observational results and their mechanistic understanding of the long-term variation of Kelvin wave activity in the equatorial lower stratosphere. Analyses are made for 15 years (1974-1988), using the rawinsonde station data at Singapore (1-degrees-N, 104-degrees-E). Occasionally, clear fluctuations with periods near two weeks can be observed in the zonal wind and temperature fields, suggesting the prominent existence of Kelvin waves. The variability of Kelvin wave activity (measured by the power spectral density integrated over periods in the range around two weeks) is clearly related to the quasi-biennial oscillation (QBO) of the zonal wind in the lower stratosphere. Around the 30 mb level, the Kelvin wave activity is vigorous when the wind regime of the QBO rapidly changes from easterlies to westerlies. In order to understand the observational results, we perform a simplified mechanistic calculation following an idea that the momentum flux due to the Kelvin wave is locally constant and suffers damping which is inversely proportional to the vertical group velocity. In this calculation the observed monthly-mean zonal wind data are used for estimating Kelvin wave amplitudes on a monthly basis. Results of the calculation represent well the long-term variation of Kelvin wave activity associated with the QBO.

その他活動・業績

  • 成層圏対流圏過程とその気候における役割(SPARC)第6回総会報告
    佐藤薫, 塩谷雅人, 余田茂男, 堀之内武, 菅原敏, 藤原正智, 秋吉英治, 渡辺真吾, 冨川喜弘, 河谷芳雄, 小林ちあき, 田口正和, 江口菜穂, 宮崎和幸, 坂崎貴俊, 高麗正史, 木下武也 天気 67 (5) 285 -293 2020年06月 [査読有り][通常論文]
  • Kazunori Ogohara, Masahiro Takagi, Shin ya Murakami, Takeshi Horinouchi, Manabu Yamada, Toru Kouyama, George L. Hashimoto, Takeshi Imamura, Yukio Yamamoto, Hiroki Kashimura, Naru Hirata, Naoki Sato, Atsushi Yamazaki, Takehiko Satoh, Naomoto Iwagami, Makoto Taguchi, Shigeto Watanabe, Takao M. Sato, Shoko Ohtsuki, Tetsuya Fukuhara, Masahiko Futaguchi, Takeshi Sakanoi, Shingo Kameda, Ko ichiro Sugiyama, Hiroki Ando, Yeon Joo Lee, Masato Nakamura, Makoto Suzuki, Chikako Hirose, Nobuaki Ishii, Takumi Abe Earth, Planets and Space 69 2017年12月01日 [査読無し][通常論文]
     
    © 2017, The Author(s). We provide an overview of data products from observations by the Japanese Venus Climate Orbiter, Akatsuki, and describe the definition and content of each data-processing level. Levels 1 and 2 consist of non-calibrated and calibrated radiance (or brightness temperature), respectively, as well as geometry information (e.g., illumination angles). Level 3 data are global-grid data in the regular longitude–latitude coordinate system, produced from the contents of Level 2. Non-negligible errors in navigational data and instrumental alignment can result in serious errors in the geometry calculations. Such errors cause mismapping of the data and lead to inconsistencies between radiances and illumination angles, along with errors in cloud-motion vectors. Thus, we carefully correct the boresight pointing of each camera by fitting an ellipse to the observed Venusian limb to provide improved longitude–latitude maps for Level 3 products, if possible. The accuracy of the pointing correction is also estimated statistically by simulating observed limb distributions. The results show that our algorithm successfully corrects instrumental pointing and will enable a variety of studies on the Venusian atmosphere using Akatsuki data.
  • Takehiko Satoh, Takehiko Satoh, Takao M. Sato, Masato Nakamura, Yasumasa Kasaba, Munetaka Ueno, Makoto Suzuki, George L. Hashimoto, Takeshi Horinouchi, Takeshi Imamura, Atsushi Yamazaki, Takayuki Enomoto, Yuri Sakurai, Kosuke Takami, Kenta Sawai, Takashi Nakakushi, Takumi Abe, Nobuaki Ishii, Chikako Hirose, Naru Hirata, Manabu Yamada, Shin Ya Murakami, Yukio Yamamoto, Tetsuya Fukuhara, Kazunori Ogohara, Hiroki Ando, Ko Ichiro Sugiyama, Hiroki Kashimura, Shoko Ohtsuki Earth, Planets and Space 69 2017年12月01日 [査読無し][通常論文]
     
    © 2017 The Author(s). The first year (December 2015 to November 2016) of IR2 after Akatsuki's successful insertion to an elongated elliptical orbit around Venus is reported with performance evaluation and results of data acquisition. The single-stage Stirling-cycle cryo-cooler of IR2 has been operated with various driving voltages to achieve the best possible cooling under the given thermal environment. A total of 3091 images of Venus (1420 dayside images at 2.02 μm and 1671 night-side images at 1.735, 2.26, and 2.32 μm) were acquired in this period. Additionally, 159 images, including images of stars for calibration and dark images for the evaluation of noise levels, were captured. Low-frequency flat images (not available in pre-launch calibration data) have been constructed using the images of Venus acquired from near the pericenter to establish the procedure to correct for the IR2 flat-field response. It was noticed that multiple reflections of infrared light in the PtSi detector caused a weak but extended tail of the point-spread function (PSF), contaminating the night-side disk of Venus with light from the much brighter dayside crescent. This necessitated the construction of an empirical PSF to remove this contamination and also to improve the dayside data by deconvolution, and this work is also discussed. Detailed astrometry is performed on star-field images in the H-band (1.65 μm), hereby confirming that the geometrical distortion of IR2 images is negligible.
  • 神山 徹, 今村 剛, 佐藤 毅彦, 中村 正人, 高木 征弘, 小郷原 一智, 樫村 博基, 佐藤 尚毅, 堀之内 武 大会講演予講集 108 366 -366 2015年
  • 大塚 成徳, 西澤 誠也, 堀之内 武, 電脳davisプロジェクト 大会講演予講集 101 409 -409 2012年
  • 西澤 誠也, 堀之内 武, 渡辺 知恵美, 伴林 晃紀, 諫本 有加, 大塚 成徳 日本惑星科学会秋期講演会予稿集 2009 61 -61 2009年09月28日
  • 諌本 有加, 渡辺 知恵美, 堀之内 武, 西澤 誠也 電子情報通信学会技術研究報告. DE, データ工学 109 (186) 21 -26 2009年08月31日 
    種類やサイズ等が増加している科学データに対して検索・解析・可視化を簡単に行うことが出来るツールGfdnviの開発を進めている.現在のGfdnaviはアクセスしているサーバ内のデータしか検索出来ない.しかし,今後複数のサーバが公開されることが予想される.そこで,我々はそれらサーバ間での横断的な検索を可能にし,研究者同士の知識を共有できるように開発を行った.その際,本研究では検索インタフェースにFaceted Navigationを導入し,ユーザが検索条件を記述することなく,複数のサーバ上のデータを探索的に検索ができるシステムを提供している.また,Gfdnaviで提供されているRESTベースのWebサービスを利用することで,柔軟な横断検索を実現した.
  • 教育研究プログラム「Elucidation of ground-based atmosphere observetion network in equatorial Asia」の初年度活動報告
    津田敏隆, 藤吉康志, 山本真之, 古本淳一, 中村卓司, 堀之内武, 岩崎杉紀 第2回赤道大気レーダーシンポジウム 第105回生存圏シンポジウム 2008年09月25日 [査読無し][通常論文]
  • 堀之内 武 プラズマ・核融合学会誌 = Journal of plasma and fusion research 84 (4) 217 -227 2008年04月25日
  • 柳平 有美, 渡辺 知恵美, 堀之内 武 日本データベース学会letters 6 (1) 153 -156 2007年06月
  • 堀之内 武, 西澤 誠也, 渡辺 知恵美, 神代 剛, 塩谷 雅人, 森川 靖大, 林 祥介, 石渡 正樹, 電脳davisプロジェクト 大会講演予講集 91 306 -306 2007年04月30日 [査読無し][通常論文]
  • 堀之内 武 天気 54 (11) 941 -944 2007年
  • Shiokawa K, S. Suzuki, Y. Otsuka, T. Ogawa, T. Nakamura, T. Horinouchi J. Geophys. Res 112 (D7) D07106 2007年 [査読無し][通常論文]
  • Tsuda Toshitaka, Nakamura Takuji, Horinouchi Takeshi Sustainable humanosphere : bulletin of Research Institute for Sustainable Humanosphere Kyoto University 2 5 -5 2006年08月31日
  • 山本 真之, 堀之内 武, 山本 衛, 橋口 浩之, 深尾 昌一郎, 庭野 将徳, 西 憲敬 大会講演予講集 90 149 -149 2006年
  • 赤道大気レーダーによる対流圏内の鉛直流観測-EAR/雲レーダーの同時観測結果について-
    山本真之, 庭野将徳, 西憲敬, 阿保真, 熊谷博, 大野裕一, 堀江宏昭, 岡本創, 永田肇, 堀之内武, 山本衛, 橋口浩之, 深尾昌一郎 「赤道大気上下結合」平成18年度公開ワークショップ集録, 2006/9/14-15, 京都市, 19-25, 2006, 2006年 [査読有り][通常論文]
  • 横山竜宏, 堀之内武, 山本衛, 深尾昌一郎 大気圏シンポジウム 18th 89 -92 2004年 [査読無し][通常論文]
  • 今村 剛, 下山 学, 堀之内 武 遊・星・人 : 日本惑星科学会誌 12 (4) 254 -260 2003年12月25日
  • 山本 真之, 親松 昌幸, 堀之内 武, 藤原 正智, 橋口 浩之, 山本 衛, 深尾 昌一郎, 山中 大学, 山中 大学 大会講演予講集 83 163 -163 2003年
  • 藤原 正智, 山本 真之, 橋口 浩之, 堀之内 武, 深尾 昌一郎 大会講演予講集 82 309 -309 2002年10月09日
  • 堀之内 武, 川那辺 直樹 情報処理学会論文誌プログラミング(PRO) 43 (8) 113 -113 2002年09月15日 
    地球・惑星流体科学において扱われるデータの多くは,離散的にサンプルされるか,広い意味で格子点上に離散化された物理量である.データの形式には,標準的なものでもいくつもあるため,オブジェクト指向のアプローチが有効である.ところで,研究のためのデータ解析においては,自由に新しい手法を開発,適用,さらに蓄積する必要があるため,(GUI よりも)プログラミングを通してデータを扱うことが必要となる.そのため,オブジェクト指向であることに加えて,エンドユーザ(すなわち研究者)が日常的にプログラミングを行うということから,素早い開発に適した言語が求められる.しかしながら,現状ではそのような言語は,まだ研究の現場ではほとんど用いられていない.我々は,オブジェクト指向スクリプト言語Ruby をこの目的で用いることができるようにするために,基礎となる数学・可視化ライブラリ等の組込みを行い,さらに,「離散化された物理量」のクラスを中心とするライブラリを開発している.この物理量クラスは,計算機上のデータの実体を隠蔽しつつ,当該分野における物理量のデータをできるだけ広くカバーするよう工夫されている.これをデータの解析・可視化対象の単位とすることで,1 つのデータ形式に限ってもプログラム開発効率が向上するだけでなく,研究者がしばしば直面する,複数の形式のデータへの対応も簡単に行えることを,いくつかの実例から示す.将来の発展としては,ネットワーク上に分散した巨大なデータセットを,少ない開発コストで扱えるプログラミング環境を構築することを目指している.Data used in earth and planetary fluid sciences are in many cases physical quantities that are discretely sampled or discretized on a grid. Since there are more than a few data formats even if we limit our scope to widely used ones, it is useful to take object-oriented approaches to handle them. Meanwhile, to analyze data it is needed for a researcher to do programming rather than to use GUI in order to flexibly develop and apply new techniques and to accumulate them. Therefore, since the end users (researchers) program daily, it would be needed a language that is suitable for rapid development as well as being object-oriented. However, such a language is rarely used in the present research activities. In order to make Ruby, an object-oriented scripting language, suitable for such activities we have ported basic libraries such as mathematical and graphic ones and are developing a library based on a class of "discretized physical quantities ". The class hides realization of data on computers and is devised to cover a wide variety of physical quantity data in the field. It is shown with examples that research program development becomes efficient by using the class even when using only one data formats and that to adopt a program to different data formats becomes easy. A future development will be directed to build a basis for rapid programming of distributed huge datasets.
  • 岩間 陽介, 堀之内 武, 津田 敏隆, SARASPRIYA Slamet, MANIK Timbul 大会講演予講集 80 230 -230 2001年10月10日
  • 豊田 英司, 石渡 正樹, 林 祥介, 竹広 真一, 堀之内 武, 地球流体電脳倶楽部, davis プロジェクト 大会講演予講集 78 429 -429 2000年10月18日 [査読無し][通常論文]
  • 豊田 英司, 石渡 正樹, 林 祥介, 赤堀 浩司, 堀之内 武, 沼口 敦, 地球流体電脳倶楽部davisプロジェクト 日本流体力学会年会講演論文集 2000 361 -362 2000年07月25日 [査読無し][通常論文]
     
    Storage format for multi-dimensional numerical data is developed for the purpose of researches mainly on geophysical fluid phenomena. In order to achieve platform-independency, netCDF is used for low-level file format. NetCDF conventions for variables and attributes are presented to realize self-descriptiveness, which flexibly support visualization information and various kind of grid-structure. A visualization and analysis software written in Fortran 90 is now under development in order to demonstrate self-descriptiveness of the data format
  • 余田 成男, 石岡 圭一, 牛丸 真司, 佐藤 薫, 堀之内 武, 向川 均 大会講演予講集 77 78 -78 2000年05月24日
  • 豊田 英司, 石渡 正樹, 林 祥介, 赤堀 浩司, 堀之内 武, 沼口 敦 大会講演予講集 77 395 -395 2000年05月24日
  • 堀之内 武, 余田 成男 大会講演予講集 71 88 -88 1997年05月
  • 第1回SPARC国際研究集会の報告
    廣田勇, 高橋正明, 塩谷雅人, 佐藤薫, 秋吉英治, 堀之内武, 内藤陽子, 荻野慎也, 清水厚, 山之内淳史 天気 44 (7) 467 -473 1997年 [査読無し][通常論文]
  • 堀之内 武, 余田 成男 大会講演予講集 69 240 -240 1996年05月21日 [査読無し][通常論文]
  • 堀之内 武, 余田 成男 大会講演予講集 67 45 -45 1995年05月15日 [査読無し][通常論文]
  • Long-term variations of Kelvin wave activity in the equatorial lowe rstratosphere
    Shiotani, M, T. Horinouchi International Symposium on Middle Atmosphere Science, Kyoto, Japan 1992年03月 [査読無し][通常論文]

受賞

  • 2015年01月 気象集誌論文賞
     
    受賞者: 堀之内 武
  • 2013年01月 気象集誌論文賞
     
    受賞者: 堀之内 武
  • 2004年 大林奨励賞
  • 1998年 山本・正野論文賞

教育活動情報

主要な担当授業

  • 大気力学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 大気、気象学、気候学、力学、地球流体力学 atmosphere, meteorology, climate, dynamics, geophysical fluid dynamics
  • 物理学Ⅰ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 運動、力、運動の法則、仕事、エネルギー、運動量、保存則、剛体、流体、単振動、音と光、干渉、回折

大学運営

委員歴

  • 2016年 - 現在   日本気象学会   理事
  • 2014年 - 現在   日本気象学会   論文誌「SOLA」副編集委員長
  • 2010年 - 現在   日本気象学会   気象集誌編集委員   日本気象学会
  • 2007年 - 2015年   国際中層大気委員会(ICMA)   Member
  • 2010年 - 2014年   日本気象学会   論文誌「SOLA」運営員
  • 2007年 - 2011年   日本気象学会   講演企画委員   日本気象学会


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