研究者データベース

加藤 知道(カトウ トモミチ)
農学研究院 連携研究部門 連携推進分野
准教授

基本情報

所属

  • 農学研究院 連携研究部門 連携推進分野

職名

  • 准教授

学位

  • 博士(理学)(2004年03月 筑波大学)
  • 農学修士(2001年03月 鳥取大学)
  • 農学士(1999年03月 北海道大学)

ホームページURL

科研費研究者番号

  • 60392958

ORCID ID

Researcher ID

  • X-7390-2019

J-Global ID

研究キーワード

  • 生態系モデル   近接リモートセンシング   気候変動   炭素循環   作物モデル   生態系生態学   データ同化   

研究分野

  • 環境・農学 / 環境動態解析
  • 自然科学一般 / 大気水圏科学
  • ライフサイエンス / 生態学、環境学
  • 人文・社会 / 地理学
  • 環境・農学 / 農業環境工学、農業情報工学

職歴

  • 2018年04月 - 現在 北海道大学 農学研究院 准教授
  • 2014年01月 - 2018年03月 北海道大学 農学研究院 テニュアトラック助教
  • 2010年11月 - 2013年12月 フランス国 気候・環境科学研究所(LSCE) ポスドク研究員
  • 2007年04月 - 2010年10月 海洋研究開発機構 地球環境フロンティア研究センター 研究員
  • 2008年10月 - 2010年09月 Research Associate, QUEST, Department of Earth Sciences, University of Bristol 日本学術振興会・海外特別研究員
  • 2004年04月 - 2007年03月 海洋研究開発機構 地球フロンティア研究システム ポスドク研究員

学歴

  • 2001年04月 - 2004年03月   筑波大学   生物科学研究科   生物学専攻
  • 1999年04月 - 2001年03月   鳥取大学   農学研究科   農林環境科学専攻
  • 1995年04月 - 1999年03月   北海道大学   農学部   農業工学科

所属学協会

  • American Geophysical Union   日本地球惑星科学連合   日本農業気象学会   日本生態学会   

研究活動情報

論文

  • Bernhard Schauberger, Hiromi Kato, Tomomichi Kato, Daiki Watanabe, Philippe Ciais
    Scientific Data 2022年12月
  • Naohisa Nakashima, Tomomichi Kato, Tomoki Morozumi, Katsuto Tsujimoto, Tomoko Kawaguchi Akitsu, Kenlo Nishida Nasahara, Shohei Murayama, Hiroyuki Muraoka, Hibiki M. Noda
    Journal of Plant Research 134 4 713 - 728 2021年07月
  • Gilberto Pastorello, Carlo Trotta, Eleonora Canfora, Housen Chu, Danielle Christianson, You-Wei Cheah, Cristina Poindexter, Jiquan Chen, Abdelrahman Elbashandy, Marty Humphrey, Peter Isaac, Diego Polidori, Alessio Ribeca, Catharine van Ingen, Leiming Zhang, Brian Amiro, Christof Ammann, M. Altaf Arain, Jonas Ardö, Timothy Arkebauer, Stefan K. Arndt, Nicola Arriga, Marc Aubinet, Mika Aurela, Dennis Baldocchi, Alan Barr, Eric Beamesderfer, Luca Belelli Marchesini, Onil Bergeron, Jason Beringer, Christian Bernhofer, Daniel Berveiller, Dave Billesbach, Thomas Andrew Black, Peter D. Blanken, Gil Bohrer, Julia Boike, Paul V. Bolstad, Damien Bonal, Jean-Marc Bonnefond, David R. Bowling, Rosvel Bracho, Jason Brodeur, Christian Brümmer, Nina Buchmann, Benoit Burban, Sean P. Burns, Pauline Buysse, Peter Cale, Mauro Cavagna, Pierre Cellier, Shiping Chen, Isaac Chini, Torben R. Christensen, James Cleverly, Alessio Collalti, Claudia Consalvo, Bruce D. Cook, David Cook, Carole Coursolle, Edoardo Cremonese, Peter S. Curtis, Ettore D’Andrea, Humberto da Rocha, Xiaoqin Dai, Kenneth J. Davis, Bruno De Cinti, Agnes de Grandcourt, Anne De Ligne, Raimundo C. De Oliveira, Nicolas Delpierre, Ankur R. Desai, Carlos Marcelo Di Bella, Paul di Tommasi, Han Dolman, Francisco Domingo, Gang Dong, Sabina Dore, Pierpaolo Duce, Eric Dufrêne, Allison Dunn, Jiří Dušek, Derek Eamus, Uwe Eichelmann, Hatim Abdalla M. ElKhidir, Werner Eugster, Cacilia M. Ewenz, Brent Ewers, Daniela Famulari, Silvano Fares, Iris Feigenwinter, Andrew Feitz, Rasmus Fensholt, Gianluca Filippa, Marc Fischer, John Frank, Marta Galvagno, Mana Gharun, Damiano Gianelle, Bert Gielen, Beniamino Gioli, Anatoly Gitelson, Ignacio Goded, Mathias Goeckede, Allen H. Goldstein, Christopher M. Gough, Michael L. Goulden, Alexander Graf, Anne Griebel, Carsten Gruening, Thomas Grünwald, Albin Hammerle, Shijie Han, Xingguo Han, Birger Ulf Hansen, Chad Hanson, Juha Hatakka, Yongtao He, Markus Hehn, Bernard Heinesch, Nina Hinko-Najera, Lukas Hörtnagl, Lindsay Hutley, Andreas Ibrom, Hiroki Ikawa, Marcin Jackowicz-Korczynski, Dalibor Janouš, Wilma Jans, Rachhpal Jassal, Shicheng Jiang, Tomomichi Kato, Myroslava Khomik, Janina Klatt, Alexander Knohl, Sara Knox, Hideki Kobayashi, Georgia Koerber, Olaf Kolle, Yoshiko Kosugi, Ayumi Kotani, Andrew Kowalski, Bart Kruijt, Julia Kurbatova, Werner L. Kutsch, Hyojung Kwon, Samuli Launiainen, Tuomas Laurila, Bev Law, Ray Leuning, Yingnian Li, Michael Liddell, Jean-Marc Limousin, Marryanna Lion, Adam J. Liska, Annalea Lohila, Ana López-Ballesteros, Efrén López-Blanco, Benjamin Loubet, Denis Loustau, Antje Lucas-Moffat, Johannes Lüers, Siyan Ma, Craig Macfarlane, Vincenzo Magliulo, Regine Maier, Ivan Mammarella, Giovanni Manca, Barbara Marcolla, Hank A. Margolis, Serena Marras, William Massman, Mikhail Mastepanov, Roser Matamala, Jaclyn Hatala Matthes, Francesco Mazzenga, Harry McCaughey, Ian McHugh, Andrew M. S. McMillan, Lutz Merbold, Wayne Meyer, Tilden Meyers, Scott D. Miller, Stefano Minerbi, Uta Moderow, Russell K. Monson, Leonardo Montagnani, Caitlin E. Moore, Eddy Moors, Virginie Moreaux, Christine Moureaux, J. William Munger, Taro Nakai, Johan Neirynck, Zoran Nesic, Giacomo Nicolini, Asko Noormets, Matthew Northwood, Marcelo Nosetto, Yann Nouvellon, Kimberly Novick, Walter Oechel, Jørgen Eivind Olesen, Jean-Marc Ourcival, Shirley A. Papuga, Frans-Jan Parmentier, Eugenie Paul-Limoges, Marian Pavelka, Matthias Peichl, Elise Pendall, Richard P. Phillips, Kim Pilegaard, Norbert Pirk, Gabriela Posse, Thomas Powell, Heiko Prasse, Suzanne M. Prober, Serge Rambal, Üllar Rannik, Naama Raz-Yaseef, David Reed, Victor Resco de Dios, Natalia Restrepo-Coupe, Borja R. Reverter, Marilyn Roland, Simone Sabbatini, Torsten Sachs, Scott R. Saleska, Enrique P. Sánchez-Cañete, Zulia M. Sanchez-Mejia, Hans Peter Schmid, Marius Schmidt, Karl Schneider, Frederik Schrader, Ivan Schroder, Russell L. Scott, Pavel Sedlák, Penélope Serrano-Ortíz, Changliang Shao, Peili Shi, Ivan Shironya, Lukas Siebicke, Ladislav Šigut, Richard Silberstein, Costantino Sirca, Donatella Spano, Rainer Steinbrecher, Robert M. Stevens, Cove Sturtevant, Andy Suyker, Torbern Tagesson, Satoru Takanashi, Yanhong Tang, Nigel Tapper, Jonathan Thom, Frank Tiedemann, Michele Tomassucci, Juha-Pekka Tuovinen, Shawn Urbanski, Riccardo Valentini, Michiel van der Molen, Eva van Gorsel, Ko van Huissteden, Andrej Varlagin, Joseph Verfaillie, Timo Vesala, Caroline Vincke, Domenico Vitale, Natalia Vygodskaya, Jeffrey P. Walker, Elizabeth Walter-Shea, Huimin Wang, Robin Weber, Sebastian Westermann, Christian Wille, Steven Wofsy, Georg Wohlfahrt, Sebastian Wolf, William Woodgate, Yuelin Li, Roberto Zampedri, Junhui Zhang, Guoyi Zhou, Donatella Zona, Deb Agarwal, Sebastien Biraud, Margaret Torn, Dario Papale
    Scientific Data 7 1 2020年12月 [査読有り][通常論文]
  • Yuan Zhang, Ana Bastos, Fabienne Maignan, Daniel Goll, Olivier Boucher, Laurent Li, Alessandro Cescatti, Nicolas Vuichard, Xiuzhi Chen, Christof Ammann, M. Altaf Arain, T. Andrew Black, Bogdan Chojnicki, Tomomichi Kato, Ivan Mammarella, Leonardo Montagnani, Olivier Roupsard, Maria J. Sanz, Lukas Siebicke, Marek Urbaniak, Francesco Primo Vaccari, Georg Wohlfahrt, Will Woodgate, Philippe Ciais
    GEOSCIENTIFIC MODEL DEVELOPMENT 13 11 5401 - 5423 2020年11月 
    Aerosol- and cloud-induced changes in diffuse light have important impacts on the global land carbon cycle, as they alter light distribution and photosynthesis in vegetation canopies. However, this effect remains poorly represented or evaluated in current land surface models. Here, we add a light partitioning module and a new canopy light transmission module to the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) land surface model (trunk version, v5453) and use the revised model, ORCHIDEE_DF, to estimate the fraction of diffuse light and its effect on gross primary production (GPP) in a multilayer canopy. We evaluate the new parameterizations using flux observations from 159 eddy covariance sites over the globe. Our results show that, compared with the original model, ORCHIDEE_DF improves the GPP simulation under sunny conditions and captures the observed higher photosynthesis under cloudier conditions in most plant functional types (PFTs). Our results also indicate that the larger GPP under cloudy conditions compared with sunny conditions is mainly driven by increased diffuse light in the morning and in the afternoon as well as by a decreased vapor pressure deficit (VPD) and decreased air temperature at midday. The observations show that the strongest positive effects of diffuse light on photosynthesis are found in the range from 5 to 20 degrees C and at a VPD < 1 kPa. This effect is found to decrease when the VPD becomes too large or the temperature falls outside of the abovementioned range, which is likely due to the increasing stomatal resistance to leaf CO2 uptake. ORCHIDEE_DF underestimates the diffuse light effect at low temperature in all PFTs and overestimates this effect at high temperature and at a high VPD in grasslands and croplands. The new model has the potential to better investigate the impact of large-scale aerosol changes and long-term changes in cloudiness on the terrestrial carbon budget, both in the historical period and in the context of future air quality policies and/or climate engineering.
  • Yuma Sakai, Hideki Kobayashi, Tomomichi Kato
    GEOSCIENTIFIC MODEL DEVELOPMENT 13 9 4041 - 4066 2020年09月 
    Global terrestrial ecosystems control the atmospheric CO2 concentration through gross primary production (GPP) and ecosystem respiration processes. Chlorophyll fluorescence is one of the energy release pathways of excess incident light in the photosynthetic process. Over the last 10 years, extensive studies have revealed that canopyscale Sun-induced chlorophyll fluorescence (SIF), which potentially provides a direct pathway to link leaf-level photosynthesis to global GPP, can be observed from satellites. SIF is used to infer photosynthetic capacity of plant canopy; however, it is not clear how the leaf-level SIF emission contributes to the top-of-canopy directional SIF. Plant canopy radiative transfer models are useful tools to understand the mechanism of anisotropic light interactions such as scattering and absorption in plant canopies. One-dimensional (1-D) plane-parallel layer models (e.g., the Soil Canopy Observation, Photochemistry and Energy fluxes (SCOPE) model) have been widely used and are useful to understand the general mechanisms behind the temporal and seasonal variations in SIF. However, a 1-D model does not explain the complexity of the actual canopy structures. Three-dimensional models (3-D) have a potential to delineate the realistic directional canopy SIFs. Forest Light Environmental Simulator for SIF (FLiES-SIF) version 1.0 is a 3-D Monte Carlo plant canopy radiative transfer model to understand the biological and physical mechanisms behind the SIF emission from complex forest canopies. The FLiES-SIF model is coupled with leaf-level fluorescence and a physiology module so that users are able to simulate how the changes in environmental and leaf traits as well as canopy structure affect the observed SIF at the top of the canopy. The FLiES-SIF model was designed as three-dimensional model, yet the entire modules are computationally efficient: FLiES-SIF can be easily run by moderate-level personal computers with lower memory demands and public software. In this model description paper, we focused on the model formulation and simulation schemes, and showed some sensitivity analysis against several major variables such as view angle and leaf area index (LAI). The simulation results show that SIF increases with LAI then saturated at LAI > 2-4 depending on the spectral wavelength. The sensitivity analysis also shows that simulated SIF radiation may decrease with LAI at a higher LAI domain (LAI > 5). These phenomena are seen in certain Sun and view angle conditions. This type of nonlinear and non-monotonic SIF behavior towards LAI is also related to spatial forest structure patterns. FLiES-SIF version 1.0 can be used to quantify the canopy SIF in various view angles including the contribution of multiple scattering which is the important component in the near-infrared domain. The potential use of the model is to standardize the satellite SIF by correcting the bidirectional effect. This step will contribute to the improvement of the GPP estimation accuracy through SIF.
  • Wu L, Kato T, Sato H, Hirano T, Yazaki T
    Forest Ecology and Management 451 1 117529 - https://doi.org/10.1016/j.fore 2019年11月 [査読有り][通常論文]
  • Marc Peaucelle, Cedric Bacour, Philippe Ciais, Nicolas Vuichard, Sylvain Kuppel, Josep Penuelas, Luca Belelli Marchesini, Peter D. Blanken, Nina Buchmann, Jiquan Chen, Nicolas Delpierre, Ankur R. Desai, Eric Dufrene, Damiano Gianelle, Cristina Gimeno-Colera, Carsten Gruening, Carole Helfter, Lukas Hortnagl, Andreas Ibrom, Richard Joffre, Tomomichi Kato, Thomas E. Kolb, Beverly Law, Anders Lindroth, Ivan Mammarella, Lutz Merbold, Stefano Minerbi, Leonardo Montagnani, Ladislav Sigut, Mark Sutton, Andrej Varlagin, Timo Vesala, Georg Wohlfahrt, Sebastian Wolf, Dan Yakir, Nicolas Viovy
    GLOBAL ECOLOGY AND BIOGEOGRAPHY 28 9 1351 - 1365 2019年09月 [査読有り][通常論文]
     
    Aim The mechanisms of plant trait adaptation and acclimation are still poorly understood and, consequently, lack a consistent representation in terrestrial biosphere models (TBMs). Despite the increasing availability of geo-referenced trait observations, current databases are still insufficient to cover all vegetation types and environmental conditions. In parallel, the growing number of continuous eddy-covariance observations of energy and CO2 fluxes has enabled modellers to optimize TBMs with these data. Past attempts to optimize TBM parameters mostly focused on model performance, overlooking the ecological properties of ecosystems. The aim of this study was to assess the ecological consistency of optimized trait-related parameters while improving the model performances for gross primary productivity (GPP) at sites. Location Worldwide. Time period 1992-2012. Major taxa studied Trees and C-3 grasses. Methods We optimized parameters of the ORCHIDEE model against 371 site-years of GPP estimates from the FLUXNET network, and we looked at global covariation among parameters and with climate. Results The optimized parameter values were shown to be consistent with leaf-scale traits, in particular, with well-known trade-offs observed at the leaf level, echoing the leaf economic spectrum theory. Results showed a marked sensitivity of trait-related parameters to local bioclimatic variables and reproduced the observed relationships between traits and climate. Main conclusions Our approach validates some biological processes implemented in the model and enables us to study ecological properties of vegetation at the canopy level, in addition to some traits that are difficult to observe experimentally. This study stresses the need for: (a) implementing explicit trade-offs and acclimation processes in TBMs; (b) improving the representation of processes to avoid model-specific parameterization; and (c) performing systematic measurements of traits at FLUXNET sites in order to gather information on plant ecophysiology and plant diversity, together with micro-meteorological conditions.
  • Yi-Ying Chen, Wei Huang, Wei-Hong Wang, Jehn-Yih Juang, Jing-Shan Hong, Tomomichi Kato, Sebastiaan Luyssaert
    SCIENTIFIC REPORTS 9 1 3643  2019年03月 [査読有り][通常論文]
     
    A new reconstruction of changes in Taiwan's land cover and estimated uncertainty between 1904 and 2015 is presented. The reconstruction is made by integrating geographical information from historical maps and SPOT satellite images, to obtain spatially explicit land cover maps with a resolution of 500 x 500 m and distinguishes six land cover classes: forests, grasslands, agricultural land, inland water, built-up land, and bare soil. The temporal resolution is unbalanced being derived from four historical maps describing the land cover between 1904 and 1994 and five mosaic satellite images describing the land cover between 1995 and 2015. The uncertainty of the historical maps is quantified to show the aggregation error whereas the uncertainty of the satellite images is quantified as classification error. Since 1904, Taiwan, as a developing country, has gone through a not unusual sequence of population growth and subsequent urbanization, a decoupling of the demand for agricultural land from population growth, and a transition from shrinking in forest area to forest expansion. This new land cover reconstruction is expected to contribute to future revisions of global land cover reconstructions as well as to studies of (gross) land cover changes, the carbon budget, regional climate, urban heat islands, and air and water pollution at the national and sub-national level.
  • Schauberger B, Ben-Ari T, Makowski, D, Kato T, Kato H, Ciais P
    Scientific Reports 15 8 16865  2018年11月 [査読有り][通常論文]
  • Hua Lin, Yajun Chen, Qinghai Song, Peili Fu, James Cleverly, Vincenzo Magliulo, Beverly E. Law, Christopher M. Gough, Lukas Hortnagl, Filippo Di Gennaro, Giorgio Matteucci, Leonardo Montagnani, Pierpaolo Duce, Changliang Shao, Tomomichi Kato, Damien Bonal, Eugenie Paul-Limoges, Jason Beringer, John Grace, Zexin Fan
    SCIENCE OF THE TOTAL ENVIRONMENT 607 1286 - 1292 2017年12月 [査読有り][通常論文]
     
    Deforestation and forest degradation cause the deterioration of resources and ecosystem services. However, there are still no operational indicators to measure forest status, especially for forest degradation. In the present study, we analysed the thermal response number (TRN, calculated by daily total net radiation divided by daily temperature range) of 163 sites including mature forest, disturbed forest, planted forest, shrubland, grassland, savanna vegetation and cropland. TRN generally increased with latitude, however the regression of TRN against latitude differed among vegetation types. Mature forests are superior as thermal buffers, and had significantly higher TRN than disturbed and planted forests. There was a clear boundary between TRN of forest and non-forest vegetation (i.e. grassland and savanna) with the exception of shrubland, whose TRN overlapped with that of forest vegetation. We propose to use the TRN of local mature forest as the optimal TRN (TRNopt). A forest with lower than 75% of TRNopt was identified as subjected to significant disturbance, and forests with 66% of TRNopt was the threshold for deforestation within the absolute latitude from 30 degrees to 55 degrees. Our results emphasized the irreplaceable thermal buffer capacity of mature forest. TRN can be used for early warning of deforestation and degradation risk. It is therefore a valuable tool in the effort to protect forests and prevent deforestation. (C) 2017 Elsevier B.V. All rights reserved.
  • Yunjun Yao, Shunlin Liang, Xianglan Li, Yuhu Zhang, Jiquan Chen, Kun Jia, Xiaotong Zhang, Joshua B. Fisher, Xuanyu Wang, Lilin Zhang, Jia Xu, Changliang Shao, Gabriela Posse, Yingnian Li, Vincenzo Magliulo, Andrej Varlagin, Eddy J. Moors, Julia Boike, Craig Macfarlane, Tomomichi Kato, Nina Buchmann, D. P. Billesbach, Jason Beringer, Sebastian Wolf, Shirley A. Papuga, Georg Wohlfahrt, Leonardo Montagnani, Jonas Ardo, Eugenie Paul-Limoges, Carmen Emmel, Lukas Hortnagl, Torsten Sachs, Carsten Gruening, Beniamino Gioli, Ana Lopez-Ballesteros, Rainer Steinbrecher, Bert Gielen
    JOURNAL OF HYDROLOGY 553 508 - 526 2017年10月 [査読有り][通常論文]
     
    Estimation of high-resolution terrestrial evapotranspiration (ET) from Landsat data is important in many climatic, hydrologic, and agricultural applications, as it can help bridging the gap between existing coarse-resolution ET products and point-based field measurements. However, there is large uncertainty among existing ET products from Landsat that limit their application. This study presents a simple Taylor skill fusion (STS) method that merges five Landsat-based ET products and directly measured ET from eddy covariance (EC) to improve the global estimation of terrestrial ET. The STS method uses a weighted average of the individual ET products and weights are determined by their Taylor skill scores (S). The validation with site-scale measurements at 206 EC flux towers showed large differences and uncertainties among the five ET products. The merged ET product exhibited the best performance with a decrease in the averaged root-mean-square error (RMSE) by 2-5 W/m(2) when compared to the individual products. To evaluate the reliability of the STS method at the regional scale, the weights of the STS method for these five ET products were determined using EC ground-measurements. An example of regional ET mapping demonstrates that the STS-merged ET can effectively integrate the individual Landsat ET products. Our proposed method provides an improved high-resolution ET product for identifying agricultural crop water consumption and providing a diagnostic assessment for global land surface models. (C) 2017 Elsevier B.V. All rights reserved.
  • Rui Ma, Li Zhang, Xiangjun Tian, Jiancai Zhang, Wenping Yuan, Yi Zheng, Xiang Zhao, Tomomichi Kato
    REMOTE SENSING 9 3 188 - doi:10.3390/rs9030188 2017年03月 [査読有り][通常論文]
     
    Quantitative estimation of the magnitude and variability of gross primary productivity (GPP) is required to study the carbon cycle of the terrestrial ecosystem. Using ecosystem models and remotely-sensed data is a practical method for accurately estimating GPP. This study presents a method for assimilating high-quality leaf area index (LAI) products retrieved from satellite data into a process-oriented Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM) to acquire accurate GPP. The assimilation methods, including the Ensemble Kalman Filter (EnKF) and a proper orthogonal decomposition (POD)-based ensemble four-dimensional (4D) variational assimilation method (PODEn4DVar), incorporate information provided by observations into the model to achieve a better agreement between the model-estimated and observed GPP. The LPJ-POD scheme performs better with a correlation coefficient of r = 0.923 and RMSD of 32.676 gC/m(2)/month compared with the LPJ-EnKF scheme (r = 0.887, RMSD = 38.531 gC/m(2)/month) and with no data assimilation (r = 0.840, RMSD = 45.410 gC/m(2)/month). Applying the PODEn4DVar method into LPJ-DGVM for simulating GPP in China shows that the annual amount of GPP in China varied between 5.92 PgC and 6.67 PgC during 2003-2012 with an annual mean of 6.35 PgC/yr. This study demonstrates that integrating remotely-sensed data with dynamic global vegetation models through data assimilation methods has potential in optimizing the simulation and that the LPJ-POD scheme shows better performance in improving GPP estimates, which can provide a favorable way for accurately estimating dynamics of ecosystems.
  • Diurnal and Seasonal Variations in the Net Ecosystem CO2 Exchange of a Pasture in the Three-River Source Region of the Qinghai− Tibetan Plateau
    Wang, H Jin, Q Li, D Chen, L Zhao, Y Tang, T Kato, S Gu
    PloS one 12 1 e0170963  2017年02月 [査読有り][通常論文]
  • Tomomichi Kato, Keita Yamada, Yanhong Tang, Naohiro Yoshida, Eitaro Wada
    ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 53 6 597 - 609 2017年 [査読有り][通常論文]
     
    On the Qinghai-Tibetan Plateau, isotopic signatures in soil-atmosphere CH4 fluxes were investigated in nine grasslands and three wetlands. In the grasslands, the fractionation factor for soil CH4 uptake, a(soil), was much smaller than the usually reported value of 0.9975-1.0095. Stepwise multiple variation analysis indicates that asoil is higher for higher soil water contents but is lower for higher C/N ratios of soil surface biomass. In the three wetlands, the soil-emitted delta C-13-CH4 was similar (-55.3 +/- 5.5% and -53.0 +/- 5.5%) in two bogs separated by > 1000 km but was lower (-63.4 +/- 6.3%) in a marsh. Environmental factors related to intrasite variations in soil-emitted delta C-13-CH4 include the soil C/N ratio, oxidation-reduction potential, soil C concentration and soil water contents. Geographical isotopic surveys revealed environmental constraints on the CH4 consumption pathways in grasslands and the biome type-specific consistency in CH4 production pathways in wetlands.
  • Jingyun Fang, Tomomichi Kato, Zhaodi Guo, Yuanhe Yang, Huifeng Hu, Haihua Shen, Xia Zhao, Ayaka W. Kishimoto-Mo, Yanhong Tang, Richard A. Houghton
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 111 26 9527 - 9532 2014年07月 [査読有り][通常論文]
     
    Forests in the middle and high latitudes of the northern hemisphere function as a significant sink for atmospheric carbon dioxide (CO2). This carbon (C) sink has been attributed to two processes: age-related growth after land use change and growth enhancement due to environmental changes, such as elevated CO2, nitrogen deposition, and climate change. However, attribution between these two processes is largely controversial. Here, using a unique time series of an age-class dataset from six national forest inventories in Japan and a new approach developed in this study (i.e., examining changes in biomass density at each age class over the inventory periods), we quantify the growth enhancement due to environmental changes and its contribution to biomass C sink in Japan's forests. We show that the growth enhancement for four major plantations was 4.0 similar to 7.7 Mg C.ha(-1) from 1980 to 2005, being 8.4-21.6% of biomass C sequestration per hectare and 4.1-35.5% of the country's total net biomass increase of each forest type. The growth enhancement differs among forest types, age classes, and regions. Our results provide, to our knowledge, the first ground-based evidence that global environmental changes can increase C sequestration in forests on a broad geographic scale and imply that both the traits and age of trees regulate the responses of forest growth to environmental changes. These findings should be incorporated into the prediction of forest C cycling under a changing climate.
  • Wenping Yuan, Wenwen Cai, Jiangzhou Xia, Jiquan Chen, Shuguang Liu, Wenjie Dong, Lutz Merbold, Beverly Law, Altaf Arain, Jason Beringer, Christian Bernhofer, Andy Black, Peter D. Blanken, Alessandro Cescatti, Yang Chen, Louis Francois, Damiano Gianelle, Ivan A. Janssens, Martin Jung, Tomomichi Kato, Gerard Kiely, Dan Liu, Barbara Marcolla, Leonardo Montagnani, Antonio Raschi, Olivier Roupsard, Andrej Varlagin, Georg Wohlfahrt
    AGRICULTURAL AND FOREST METEOROLOGY 192 108 - 120 2014年07月 [査読有り][通常論文]
     
    Simulating gross primary productivity (GPP) of terrestrial ecosystems has been a major challenge in quantifying the global carbon cycle. Many different light use efficiency (LUE) models have been developed recently, but our understanding of the relative merits of different models remains limited. Using CO2 flux measurements from multiple eddy covariance sites, we here compared and assessed major algorithms and performance of seven LUE models (CASA, CFix, CFlux, EC-LUE, MODIS, VPM and VPRM). Comparison between simulated GPP and estimated GPP from flux measurements showed that model performance differed substantially among ecosystem types. In general, most models performed better in capturing the temporal changes and magnitude of GPP in deciduous broadleaf forests and mixed forests than in evergreen broadleaf forests and shrublands. Six of the seven LUE models significantly underestimated GPP during cloudy days because the impacts of diffuse radiation on light use efficiency were ignored in the models. CFlux and EC-LUE exhibited the lowest root mean square error among all models at 80% and 75% of the sites, respectively. Moreover, these two models showed better performance than others in simulating interannual variability of GPP. Two pairwise comparisons revealed that the seven models differed substantially in algorithms describing the environmental regulations, particularly water stress, on GPP. This analysis highlights the need to improve representation of the impacts of diffuse radiation and water stress in the LUE models. (C) 2014 Elsevier B.V. All rights reserved.
  • Jingyun Fang, Zhaodi Guo, Huifeng Hu, Tomomichi Kato, Hiroyuki Muraoka, Yowhan Son
    GLOBAL CHANGE BIOLOGY 20 6 2019 - 2030 2014年06月 [査読有り][通常論文]
     
    Forests play an important role in regional and global carbon (C) cycles. With extensive afforestation and reforestation efforts over the last several decades, forests in East Asia have largely expanded, but the dynamics of their C stocks have not been fully assessed. We estimated biomass C stocks of the forests in all five East Asian countries (China, Japan, North Korea, South Korea, and Mongolia) between the 1970s and the 2000s, using the biomass expansion factor method and forest inventory data. Forest area and biomass C density in the whole region increased from 179.78x10(6)ha and 38.6 Mg Cha(-1) in the 1970s to 196.65x10(6) ha and 45.5 Mg Cha(-1) in the 2000s, respectively. The C stock increased from 6.9Pg C to 8.9Pg C, with an averaged sequestration rate of 66.9 Tg Cyr(-1). Among the five countries, China and Japan were two major contributors to the total region's forest C sink, with respective contributions of 71.1% and 32.9%. In China, the areal expansion of forest land was a larger contributor to C sinks than increased biomass density for all forests (60.0% vs. 40.0%) and for planted forests (58.1% vs. 41.9%), while the latter contributed more than the former for natural forests (87.0% vs. 13.0%). In Japan, increased biomass density dominated the C sink for all (101.5%), planted (91.1%), and natural (123.8%) forests. Forests in South Korea also acted as a C sink, contributing 9.4% of the total region's sink because of increased forest growth (98.6%). Compared to these countries, the reduction in forest land in both North Korea and Mongolia caused a C loss at an average rate of 9.0 Tg Cyr(-1), equal to 13.4% of the total region's C sink. Over the last four decades, the biomass C sequestration by East Asia's forests offset 5.8% of its contemporary fossil-fuel CO2 emissions.
  • Jiangzhou Xia, Shunlin Liang, Jiquan Chen, Wenping Yuan, Shuguang Liu, Linghao Li, Wenwen Cai, Li Zhang, Yang Fu, Tianbao Zhao, Jinming Feng, Zhuguo Ma, Mingguo Ma, Shaomin Liu, Guangsheng Zhou, Jun Asanuma, Shiping Chen, Mingyuan Du, Gombo Davaa, Tomomichi Kato, Qiang Liu, Suhong Liu, Shenggong Li, Changliang Shao, Yanhong Tang, Xiang Zhao
    PLoS ONE 9 5 2014年05月20日 [査読有り][通常論文]
     
    The regression tree method is used to upscale evapotranspiration (ET) measurements at eddy-covariance (EC) towers to the grassland ecosystems over the Dryland East Asia (DEA). The regression tree model was driven by satellite and meteorology datasets, and explained 82% and 76% of the variations of ET observations in the calibration and validation datasets, respectively. The annual ET estimates ranged from 222.6 to 269.1 mm yr-1 over the DEA region with an average of 245.8 mm yr-1 from 1982 through 2009. Ecosystem ET showed decreased trends over 61% of the DEA region during this period, especially in most regions of Mongolia and eastern Inner Mongolia due to decreased precipitation. The increased ET occurred primarily in the western and southern DEA region. Over the entire study area, water balance (the difference between precipitation and ecosystem ET) decreased substantially during the summer and growing season. Precipitation reduction was an important cause for the severe water deficits. The drying trend occurring in the grassland ecosystems of the DEA region can exert profound impacts on a variety of terrestrial ecosystem processes and functions. © 2014 Xia et al.
  • Xianglan Li, Shunlin Liang, Wenping Yuan, Guirui Yu, Xiao Cheng, Yang Chen, Tianbao Zhao, Jinming Feng, Zhuguo Ma, Mingguo Ma, Shaomin Liu, Jiquan Chen, Changliang Shao, Shenggong Li, Xudong Zhang, Zhiqiang Zhang, Ge Sun, Shiping Chen, Takeshi Ohta, Andrej Varlagin, Akira Miyata, Kentaro Takagi, Nobuko Saiqusa, Tomomichi Kato
    Ecohydrology 7 1 139 - 149 2014年02月 [査読有り][通常論文]
     
    Quantifying regional evapotranspiration (ET) and environmental constraints are particularly important for understanding water and carbon cycles of terrestrial ecosystems. However, a large uncertainty in the regional estimation of ET still remains for the terrestrial ecosystems in China. This study used ET measurements of 34 eddy covariance sites within China and adjacent regions to examine the performance of the revised Remote Sensing-Penman Monteith (RS-PM) model over various ecosystem types including forests, grasslands, wetlands and croplands. No significant systematic error was found in the revised RS-PM model predictions, which explained 61% of the ET variations at all of the validation sites. Regional patterns of ET at a spatial resolution of 10×10km were quantified using a meteorology dataset from 753 meteorological stations, Modern Era Retrospective-analysis for Research and Applications (MERRA) reanalysis products and satellite data such as the Advanced Very High Resolution Radiometer (AVHRR) leaf area index. ET decreased from the southeast of China toward the northwest. Relatively high ET values were found in the southern China such as Yunnan, Hainan, Fujian and Guangdong Provinces, whereas low ET values occurred in northwestern China such as in the Xinjiang autonomous region. On average, the annual ET presented an increasing trend during the 1982-2009, with relatively low ET in 1985, 1993, 1997, 2000 and 2009. We found that the mean annual ET was higher than world average, ranging spatially between 484 and 521mmyr-1, with a mean value of 500mmyr-1, which accounted for approximately 5·6-8·3% of the world's total land-surface ET. © 2012 John Wiley & Sons, Ltd.
  • Li Zhang, Huadong Guo, Gensuo Jia, Bruce Wylie, Tagir Gilmanov, Danny Howard, Lei Ji, Jingfeng Xiao, Jing Li, Wenping Yuan, Tianbao Zhao, Shiping Chen, Guangsheng Zhou, Tomomichi Kato
    AGRICULTURAL AND FOREST METEOROLOGY 184 71 - 81 2014年01月 [査読有り][通常論文]
     
    Grassland is one of the widespread biome types globally, and plays an important role in the terrestrial carbon cycle. We examined net ecosystem production (NEP) for the temperate grasslands in northern China from 2000 to 2010. We combined flux observations, satellite data, and climate data to develop a piece-wise regression model for NEP, and then used the model to map NEP for grasslands in northern China. Over the growing season, the northern China's grassland had a net carbon uptake of 158 +/- 25 g Cm-2 during 2000-2010 with the mean regional NEP estimate of 126 TgC. Our results showed generally higher grassland NEP at high latitudes (northeast) than at low latitudes (central and west) because of different grassland types and environmental conditions. In the northeast, which is dominated by meadow steppes, the growing season NEP generally reached 200-300 g Cm-2. In the southwest corner of the region, which is partially occupied by alpine meadow systems, the growing season NEP also reached 200-300 g C m(-2). In the central part, which is dominated by typical steppe systems, the growing season NEP generally varied in the range of 100-200 g Cm-2. The NEP of the northern China's grasslands was highly variable through years, ranging from 129 (2001) to 217 gCm(-2) growing season(-1) (2010). The large interannual variations of NEP could be attributed to the sensitivity of temperate grasslands to climate changes and extreme climatic events. The droughts in 2000, 2001, and 2006 reduced the carbon uptake over the growing season by 11%, 29%, and 16% relative to the long-term (2000-2010) mean. Over the study period (2000-2010), precipitation was significantly correlated with NEP for the growing season (R-2 = 0.35, p-value < 0.1), indicating that water availability is an important stressor for the productivity of the temperate grasslands in semi-arid and arid regions in northern China. We conclude that northern temperate grasslands have the potential to sequester carbon, but the capacity of carbon sequestration depends on grassland types and environmental conditions. Extreme climate events like drought can significantly reduce the net carbon uptake of grasslands. (C) 2013 Elsevier B.V. All rights reserved.
  • M. Van Oijen, J. Balkovic, C. Beer, D. R. Cameron, P. Ciais, W. Cramer, T. Kato, M. Kuhnert, R. Martin, R. Myneni, A. Rammig, S. Rolinski, J. -F. Soussana, K. Thonicke, M. Van der Velde, L. Xu
    BIOGEOSCIENCES 11 22 6357 - 6375 2014年 [査読有り][通常論文]
     
    We analyse how climate change may alter risks posed by droughts to carbon fluxes in European ecosystems. The approach follows a recently proposed framework for risk analysis based on probability theory. In this approach, risk is quantified as the product of hazard probability and ecosystem vulnerability. The probability of a drought hazard is calculated here from the Standardized Precipitation-Evapotranspiration Index (SPEI). Vulnerability is calculated from the response to drought simulated by process-based vegetation models. We use six different models: three for generic vegetation (JSBACH, LPJmL, ORCHIDEE) and three for specific ecosystems (Scots pine forests: BASFOR; winter wheat fields: EPIC; grasslands: PASIM). The periods 1971-2000 and 2071-2100 are compared. Climate data are based on gridded observations and on output from the regional climate model REMO using the SRES A1B scenario. The risk analysis is carried out for similar to 18 000 grid cells of 0.25 x 0.25 degrees across Europe. For each grid cell, drought vulnerability and risk are quantified for five seasonal variables: net primary and ecosystem productivity (NPP, NEP), heterotrophic respiration (Rh), soil water content and evapotranspiration. In this analysis, climate change leads to increased drought risks for net primary productivity in the Mediterranean area: five of the models estimate that risk will exceed 15 %. The risks increase mainly because of greater drought probability; ecosystem vulnerability will increase to a lesser extent. Because NPP will be affected more than Rh, future carbon sequestration (NEP) will also be at risk predominantly in southern Europe, with risks exceeding 0.25 g Cm-2 d(-1) according to most models, amounting to reductions in carbon sequestration of 20 to 80 %.
  • Yu Zhou, Li Zhang, Jingfeng Xiao, Shiping Chen, Tomomichi Kato, Guangsheng Zhou
    RANGELAND ECOLOGY & MANAGEMENT 67 1 9 - 18 2014年01月 [査読有り][通常論文]
     
    Gross primary productivity (GPP) is a key component of ecosystem carbon fluxes and the carbon balance between the biosphere and the atmosphere. Accurate estimation of GPP is essential for quantifying plant production and carbon balance for grasslands. Satellite-derived vegetation indices (VIs) are often used to approximate GPP. The widely used VIs include atmospherically resistant vegetation index, enhanced vegetation index (EVI), normalized difference greenness index, normalized difference vegetation index, reduced simple ratio, ratio vegetation index, and soil-adjusted vegetation index (SAVI). The evaluation of the performance of these VIs for approximating GPP, however, has been limited to one or two VIs and/or using GPP observations from one or two sites. In this study, we examined the relationships between the nine VIs derived from the moderate resolution imaging spectroradiometer (MODIS) and tower-based GPP at five eddy covariance flux sites over the grasslands of northern China. Our results showed that the nine VIs were generally good predictors of GPP for grasslands of northern China. Overall, EVI was the best predictor. The correlation between EVI and GPP also declined from the south to the north, indicating that EVI and GPP exhibited closer relationships in more southerly sites with higher vegetation cover. We also examined the seasonal influence on the correlation between VIs and GPP. SAVI exhibited the best correlation with GPP in spring when the grassland canopy was sparse, while EVI exhibited the best correlation with GPP in summer when the grassland cover was dense. Our results also showed that VIs could capture variations in observed GPP better in drought period than in nondrought period for an alpine meadow site because of the suppression of vegetation growth by drought.
  • Jingfeng Xiao, Ge Sun, Jiquan Chen, Hui Chen, Shiping Chen, Gang Dong, Shenghua Gao, Haiqiang Guo, Jixun Guo, Shijie Han, Tomomichi Kato, Yuelin Li, Guanghui Lin, Weizhi Lu, Mingguo Ma, Steven McNulty, Changliang Shao, Xufeng Wang, Xiao Xie, Xudong Zhang, Zhiqiang Zhang, Bin Zhao, Guangsheng Zhou, Jie Zhou
    Agricultural and Forest Meteorology 182-183 76 - 90 2013年12月15日 [査読有り][通常論文]
     
    The magnitude, spatial patterns, and controlling factors of the carbon and water fluxes of terrestrial ecosystems in China are not well understood due to the lack of ecosystem-level flux observations. We synthesized flux and micrometeorological observations from 22 eddy covariance flux sites across China, and examined the carbon fluxes, evapotranspiration (ET), and water use efficiency (WUE) of terrestrial ecosystems at the annual scale. Our results show that annual carbon and water fluxes exhibited clear latitudinal patterns across sites. Both annual gross primary productivity (GPP) and ecosystem respiration (ER) declined with increasing latitude, leading to a declining pattern in net ecosystem productivity (NEP) with increasing latitude. Annual ET also generally declined with increasing latitude. The spatial patterns of annual carbon and water fluxes were mainly driven by annual temperature, precipitation, and growing season length. Carbon fluxes, ET, and water use efficiency (WUE) varied with vegetation type. Overall, forest and cropland sites had higher annual fluxes than grassland sites, and the annual fluxes of coastal wetland sites were similar to or slightly higher than those of forest sites. Annual WUE was associated with annual precipitation, GPP, and growing season length. Higher-productivity ecosystems (forests and coastal wetlands) also had higher WUE than lower-productivity ecosystems (grasslands and croplands). The strong relationships between annual GPP and ET demonstrated the coupling of the carbon and water cycles. Our results show that forest plantations had high annual NEP and WUE, and could provide larger carbon sequestration capacity than natural forests. The coastal salt marsh and mangrove ecosystems also had high carbon sequestration capacity. Efforts to strengthen China's terrestrial carbon sink should focus on ecosystems such as forest plantations in southern China where heat and water are ideal for maintaining high productivity. This strategy is especially important because efforts to increase carbon sequestration in areas of limited water may inadvertently contribute to the ongoing water crisis in northern China. © 2013 Elsevier B.V.
  • Tomomichi Kato, Keita Yamada, Yanhong Tang, Naohiro Yoshida, Eitaro Wada
    ATMOSPHERIC ENVIRONMENT 77 338 - 347 2013年10月 [査読有り][通常論文]
     
    To understand the mechanisms of soil CH4 consumption and production in alpine ecosystems, we for the first time examined the stable carbon isotope ratio of CH4 (delta C-13-CH4) at three major grassland vegetation types, alpine meadow, alpine shrub, and alpine wetland, on the Qinghai-Tibetan Plateau. The alpine meadow and shrub showed net CH4 absorption in their vertical profiles of CH4 concentration in summer, but a difference in their processes. Whereas the alpine shrub was dominated by CH4 consumption in its soil profile, CH4 production in the alpine meadow could slightly cancel consumed CH4 in shallow soil from 0.3 to 0.1 m. This potential CH4 production can be attributed to the relatively wet soil type of that ecosystem, which might allow methanogenesis to act in moist soil lumps in the shallow layer. The alpine wetland differed in methane production, consumption, and transport pathways between hummock and hollow plots. In summer, both plots were enriched in C-13-CH4 in dissolved CH4 in soil pore water, suggesting that CH4 production was conducted mainly by acetate fermentation. In autumn, CH4 production was shifted toward CO2/H-2 reduction. Furthermore, in hummocks, plant-mediated transport of CH4 by vascular plants appeared to perform passive CH4 flow from deep soil to atmosphere, which allowed the produced CH4 to bypass the oxidation zone in shallow soil. In hollows, however, CH4 produced in shallow soil was subject to simultaneous oxidation. The fractional oxidation rate on gross CH4 production in hollows was estimated by simple mass balance model at 7-17% in summer and 35-36% in autumn. (C) 2013 Elsevier Ltd. All rights reserved.
  • Tomomichi Kato, Sakae Toyoda, Naohiro Yoshida, Yanhong Tang, Eitaro Wada
    RAPID COMMUNICATIONS IN MASS SPECTROMETRY 27 13 1517 - 1526 2013年07月 [査読有り][通常論文]
     
    RATIONALE Static-chamber flux measurements have suggested that one of the world's largest grasslands, the Qinghai-Tibetan Plateau (QTP), is a potential source of nitrous oxide (N2O), a major greenhouse gas. However, production and consumption pathways of N2O have not been identified by in situ field measurements. METHODS Ratios of N2O isotopomers (14N15N16O and 15N14N16O) and an isotopologue (14N14N18O) with respect to 14N14N16O in the atmosphere, static chambers, and soils were measured by gas chromatography and mass spectrometry in the summer of 2005 and the following winter of 2006 at three typical alpine ecosystems: alpine meadow, alpine shrub, and alpine wetland, on the QTP, China. RESULTS Site preference (SP) values of soil-emitted N2O were estimated as 33.7 parts per thousand and 30.1 parts per thousand for alpine meadow and shrub, respectively, suggesting larger contributions by fungal denitrification, than by bacterial denitrification and nitrifier-denitrification, to N2O production. Statistical analysis of the relationship between SP and 15Nbulk values indicated that in alpine meadow, shrub, and wetland sites fungal denitrification contributed 40.7%, 40.0%, and 23.2% to gross N2O production and the produced N2O was reduced by 87.6%, 82.9%, and 92.7%, respectively. CONCLUSIONS The combined measurements of N2O concentration, flux, and isotopomeric signatures provide a robust estimation of N2O circulation dynamics in alpine ecosystems on the QTP, which would contribute to the development of ecosystem nitrogen cycle model. Copyright (c) 2013 John Wiley & Sons, Ltd.
  • Xianglan Li, Shunlin Liang, Guirui Yu, Wenping Yuan, Xiao Cheng, Jiangzhou Xia, Tianbao Zhao, Jinming Feng, Zhuguo Ma, Mingguo Ma, Shaomin Liu, Jiquan Chen, Changliang Shao, Shenggong Li, Xudong Zhang, Zhiqiang Zhang, Shiping Chen, Takeshi Ohta, Andrej Varlagin, Akira Miyata, Kentaro Takagi, Nobuko Saiqusa, Tomomichi Kato
    ECOLOGICAL MODELLING 261 80 - 92 2013年07月 [査読有り][通常論文]
     
    Gross primary production (GPP) is of significant importance for the terrestrial carbon budget and climate change, but large uncertainties in the regional estimation of GPP still remain over the terrestrial ecosystems in China. Eddy covariance (EC) flux towers measure continuous ecosystem-level exchange of carbon dioxide (CO2) and provide a promising way to estimate GPP. We used the measurements from 32 EC sites to examine the performance of a light use efficiency model (i.e., EC-LUE) at various ecosystem types, including 23 sites in China and 9 sites in adjacent areas with the similar climate environments. No significant systematic error was found in the EC-LUE model predictions, which explained 79% and 62% of the GPP variation at the validation sites with C-3 and C-4 vegetation, respectively. Regional patterns of GPP at a spatial resolution of 10 km x 10 km from 2000 to 2009 were determined using the MERRA (Modern Era Retrospective-analysis for Research and Applications) reanalysis dataset and MODIS (MOD-erate resolution Imaging Spectroradiometer). China's terrestrial GPP decreased from southeast toward the northwest, with the highest values occurring over tropical forests areas, and the lowest values in dry regions. The annual GPP of land in China varied between 5.63 Pg C and 6.39 Pg C, with a mean value of 6.04 Pg C, which accounted for 4.90-6.29% of the world's total terrestrial GPP. The GPP densities of most vegetation types in China such as evergreen needleleaf forests, deciduous needleleaf forests, mixed forests, woody savannas, and permanent wetlands were much higher than the respective global GPP densities. However, a high proportion of sparsely vegetated area in China resulted in the overall low GPP. The inter-annual variability in GPP was significantly influenced by air temperature (R-2 = 0.66, P < 0.05), precipitation (R-2 = 0.71, P < 0.05), and normalized difference vegetation index (NDVI) (R-2 = 0.83, P < 0.05), respectively. Published by Elsevier B.V.
  • Kazuhito Ichii, Masayuki Kondo, Young-Hee Lee, Shao-Qiang Wang, Joon Kim, Masahito Ueyama, Hee-Jeong Lim, Hao Shi, Takashi Suzuki, Akihiko Ito, Hyojung Kwon, Weimin Ju, Mei Huang, Takahiro Sasai, Jun Asanuma, Shijie Han, Takashi Hirano, Ryuichi Hirata, Tomomichi Kato, Sheng-Gong Li, Ying-Nian Li, Takahisa Maeda, Akira Miyata, Yojiro Matsuura, Shohei Murayama, Yuichiro Nakai, Takeshi Ohta, Taku M. Saitoh, Nobuko Saigusa, Kentaro Takagi, Yan-Hong Tang, Hui-Min Wang, Gui-Rui Yu, Yi-Ping Zhang, Feng-Hua Zhao
    JOURNAL OF FOREST RESEARCH 18 1 13 - 20 2013年02月 [査読有り][通常論文]
     
    Based on the model-data comparison at the eddy-covariance observation sites from CarboEastAsia datasets, we report the current status of the terrestrial carbon cycle modeling in monsoon Asia. In order to assess the modeling performance and discuss future requirements for both modeling and observation efforts in Asia, we ran eight terrestrial biosphere models at 24 sites from 1901 to 2010. By analyzing the modeled carbon fluxes against the CarboEastAsia datasets, the strengths and weaknesses of terrestrial biosphere modeling over Asia were evaluated. In terms of pattern and magnitude, the carbon fluxes (i.e., gross primary productivity, ecosystem respiration, and net ecosystem exchange) at the temperate and boreal forest sites were simulated best, whereas the simulation results from the tropical forest, cropland, and disturbed sites were poor. The multi-model ensemble mean values showed lower root mean square errors and higher correlations, suggesting that composition of multiple terrestrial biosphere models would be preferable for terrestrial carbon budget assessments in Asia. These results indicate that the current model-based estimation of terrestrial carbon budget has large uncertainties, and future research should further refine the models to permit re-evaluation of the terrestrial carbon budget.
  • Nobuko Saigusa, Sheng-Gong Li, Hyojung Kwon, Kentaro Takagi, Lei-Ming Zhang, Reiko Ide, Masahito Ueyama, Jun Asanuma, Young-Jean Choi, Jung Hwa Chun, Shi-Jie Han, Takashi Hirano, Ryuichi Hirata, Minseok Kang, Tomomichi Kato, Joon Kim, Ying-Nian Li, Takahisa Maeda, Akira Miyata, Yasuko Mizoguchi, Shohei Murayama, Yuichiro Nakai, Takeshi Ohta, Taku M. Saitoh, Hui-Ming Wang, Gui-Rui Yu, Yi-Ping Zhang, Feng-Hua Zhao
    JOURNAL OF FOREST RESEARCH 18 1 41 - 48 2013年02月 [査読有り][通常論文]
     
    The datasets of net ecosystem CO2 exchange (NEE) were acquired from 21 forests, 3 grasslands, and 3 croplands in the eastern part of Asia based on the eddy covariance measurements of the international joint program, CarboEastAsia. The program was conducted by three networks in Asia, ChinaFLUX, JapanFlux, and KoFlux, to quantify, synthesize, and understand the carbon budget of the eastern part of Asia. An intercomparison was conducted for NEE estimated by three gap-filling procedures adopted by ChinaFLUX, JapanFlux, and KoFlux to test the range of uncertainty in the estimation of NEE. The overall comparison indicated good agreement among the procedures in the seasonal patterns of NEE, although a bias was observed in dormant seasons depending on the different criteria of data screening. Based on the gap-filled datasets, the magnitude and seasonality of the carbon budget were compared among various biome types, phenology, and stress conditions throughout Asia. The annual values of gross primary production and ecosystem respiration were almost proportional to the annual air temperature. Forest management, including clear-cutting, plantation, and artificial drainage, was significant and obviously affected the annual carbon uptake within the forests. Agricultural management resulted in notable seasonal patterns in the crop sites. The dataset obtained from a variety of biome types would be an essential source of knowledge for ecosystem science as well as a valuable validation dataset for modeling and remote sensing to upscale the carbon budget estimations in Asia.
  • T. Kato, W. Knorr, M. Scholze, E. Veenendaal, T. Kaminski, J. Kattge, N. Gobron
    Biogeosciences 10 2 789 - 802 2013年 [査読有り][通常論文]
     
    Terrestrial productivity in semi-arid woodlands is strongly susceptible to changes in precipitation, and semiarid woodlands constitute an important element of the global water and carbon cycles. Here, we use the Carbon Cycle Data Assimilation System (CCDAS) to investigate the key parameters controlling ecological and hydrological activities for a semi-arid savanna woodland site in Maun, Botswana. Twenty-four eco-hydrological process parameters of a terrestrial ecosystem model are optimized against two data streams separately and simultaneously: daily averaged latent heat flux (LHF) derived from eddy covariance measurements, and decadal fraction of absorbed photosynthetically active radiation (FAPAR) derived from the Sea-viewing Wide Field-ofview Sensor (SeaWiFS). Assimilation of both data streams LHF and FAPAR for the years 2000 and 2001 leads to improved agreement between measured and simulated quantities not only for LHF and FAPAR, but also for photosynthetic CO2 uptake. The mean uncertainty reduction (relative to the prior) over all parameters is 14.9% for the simultaneous assimilation of LHF and FAPAR, 8.5% for assimilating LHF only, and 6.1% for assimilating FAPAR only. The set of parameters with the highest uncertainty reduction is similar between assimilating only FAPAR or only LHF. The highest uncertainty reduction for all three cases is found for a parameter quantifying maximum plant-available soil moisture. This indicates that not only LHF but also satellite-derived FAPAR data can be used to constrain and indirectly observe hydrological quantities. © Author(s) 2013.
  • Tomomichi Kato, Mitsuru Hirota, Yanhong Tang, Eitaro Wada
    ATMOSPHERIC ENVIRONMENT 45 31 5632 - 5639 2011年10月 [査読有り][通常論文]
     
    The intra- and inter-site spatial variability of methane (CH4) and nitrous oxide (N2O) fluxes were investigated in three alpine ecosystems at Haibei station on the Qinghai Tibetan Plateau (QTP) in summer 2005 and in sixteen alpine ecosystems with various vegetations across the QTP in summer 2006, respectively. The magnitude of average CH4 emissions from wetlands was at least 100 times larger than average CH4 uptake by grassland, suggesting that the entire QTP is likely to be a source of methane in summertime because of a significant fractional area of wetlands (similar to 2.2%) on the plateau. Intra-site investigation, with sixteen chambers, revealed a significant negative relationship of CH4 emissions with the C/N ratio of aboveground biomass and soil pH in the alpine wetland when all chambers were considered. Moreover, soil oxidation-reduction potential (ORP) had a remarkably strong influence on CH4 emissions for nine chambers above the water level, resulting in a negative exponential relationship. For N2O flux in alpine meadows, a negative relationship with both soil pH and livestock dung biomass was observed. Aboveground plant biomass and soil pH were important variables overall in wetlands. Inter-site investigation found positive and negative relationships between CH4 flux and soil biomass to 5 cm depth in nine grassland and seven wetland sites, respectively. N2O flux showed a moderately strong negative exponential relationship with the C/N ratio of surface soil in the grassland sites. In the wetlands, soil pH was negatively correlated with N2O flux, perhaps due to both reduced N2O release from suppressed nitrification and denitrification. (C) 2011 Elsevier Ltd. All rights reserved.
  • Y. Wang, J. Y. Fang, T. Kato, Z. D. Guo, B. Zhu, W. H. Mo, Y. H. Tang
    BIOGEOSCIENCES 8 8 2099 - 2106 2011年 [査読有り][通常論文]
     
    Recent studies based on remote sensing and carbon process models have revealed that terrestrial net primary production (NPP) in the middle and high latitudes of the Northern Hemisphere has increased significantly; this is crucial for explaining the increased terrestrial carbon sink in the past several decades. Regional NPP estimation based on significant field data, however, has been rare. In this study, we estimated the long-term changes in aboveground NPP (ANPP) for Japan's forests from 1980 to 2005 using forest inventory data, direct field measurements, and an allometric method. The overall ANPP for all forest types averaged 10.5 Mg ha(-1) yr(-1), with a range of 9.6 to 11.5 Mg ha(-1) yr(-1), and ANPP for the whole country totaled 249.1 Tg yr(-1) (range: 230.0 to 271.4 Tg yr(-1)) during the study period. Over the 25 years, the net effect of increased ANPP in needle-leaf forests and decreased ANPP in broadleaf forests has led to an increase of 1.9 Mg ha(-1) yr(-1) (i.e., 0.79% yr(-1)). This increase may be mainly due to the establishment of plantations and the rapid early growth of these planted forests.
  • Akihiko Ito, Kazuhito Ichii, Tomomichi Kato
    ECOLOGICAL RESEARCH 25 5 1033 - 1044 2010年09月 [査読有り][通常論文]
     
    We used terrestrial ecosystem models to estimate spatial and temporal variability in and uncertainty of estimated soil carbon dioxide (CO2) efflux, or soil respiration, over the Japanese Archipelago. We compared five carbon-cycle models to assess inter-model variability: Biome-BGC, CASA, LPJ, SEIB, and VISIT. These models differ in approaches to soil carbon dynamics, root respiration estimation, and relationships between decomposition and environmental factors. We simulated the carbon budget of natural ecosystems over the archipelago for 2001-2006 at 1-day time steps and 2-min (latitude and longitude) spatial resolution. The models were calibrated using measured flux data to accurately represent net ecosystem CO2 exchange. Each model successfully reproduced seasonal changes and latitudinal gradients in soil respiration. The five-model average of estimated total soil respiration of Japanese ecosystems was 295 Tg C year(-1), with individual model estimates ranging from 210 to 396 Tg C year(-1) (1 Tg = 10(12) g). The differences between modeled estimates were more evident in summer and in warmer years, implying that they were mainly attributable to differences in modeling the temperature dependence of soil respiration. There was a large discrepancy between models in the estimated contribution of roots to total soil respiration, ranging from 3.9 to 48.4%. Although model calibration reduced the uncertainty of flux estimates, substantial uncertainties still remained in estimates of underground processes from these terrestrial carbon-cycle models.
  • K. Ichii, T. Suzuki, T. Kato, A. Ito, T. Hajima, M. Ueyama, T. Sasai, R. Hirata, N. Saigusa, Y. Ohtani, K. Takagi
    BIOGEOSCIENCES 7 7 2061 - 2080 2010年 [査読有り][通常論文]
     
    Terrestrial biosphere models show large differences when simulating carbon and water cycles, and reducing these differences is a priority for developing more accurate estimates of the condition of terrestrial ecosystems and future climate change. To reduce uncertainties and improve the understanding of their carbon budgets, we investigated the utility of the eddy flux datasets to improve model simulations and reduce variabilities among multi-model outputs of terrestrial biosphere models in Japan. Using 9 terrestrial biosphere models (Support Vector Machine - based regressions, TOPS, CASA, VISIT, Biome-BGC, DAYCENT, SEIB, LPJ, and TRIFFID), we conducted two simulations: (1) point simulations at four eddy flux sites in Japan and (2) spatial simulations for Japan with a default model (based on original settings) and a modified model (based on model parameter tuning using eddy flux data). Generally, models using default model settings showed large deviations in model outputs from observation with large model-by-model variability. However, after we calibrated the model parameters using eddy flux data (GPP, RE and NEP), most models successfully simulated seasonal variations in the carbon cycle, with less variability among models. We also found that interannual variations in the carbon cycle are mostly consistent among models and observations. Spatial analysis also showed a large reduction in the variability among model outputs. This study demonstrated that careful validation and calibration of models with available eddy flux data reduced model-by-model differences. Yet, site history, analysis of model structure changes, and more objective procedure of model calibration should be included in the further analysis.
  • Jin Chen, Miaogen Shen, Tomomichi Kato
    JOURNAL OF PLANT ECOLOGY 2 4 173 - 185 2009年12月 [査読有り][通常論文]
     
    Light-use efficiency (LUE) is an important tool for scaling up local CO2 flux (F-CO2) tower observations to regional and global carbon dynamics. Using a data set includingF(CO2) and environmental factors obtained from an alpine meadow on the Tibetan Plateau, we examined both diurnal and seasonal changes in LUE and the environmental factors controlling these changes. Our objectives were to (i) characterize the diurnal and daily variability of LUE in an alpine meadow, (ii) clarify the causes of this variability, and (iii) explore the possibility of applying the LUE approach to this alpine meadow by examining the relationship between daily LUE and hourly LUE at satellite visiting times. First, we obtained the LUE-the ratio of the gross primary production (GPP) to the absorbed photosynthetically active radiation (APAR)-from the flux tower and meteorological observations. We then characterized the patterns of diurnal and seasonal changes in LUE, explored the environmental controls on LUE using univariate regression analyses and evaluated the effects of diffuse radiation on LUE by assigning weights through a linear programming method to beam photosynthetically active radiation (PAR) and diffuse PAR, which were separated from meteorological observations using an existing method. Finally, we examined the relationships between noontime hourly LUE and daily LUE and those between adjusted noontime hourly and daily LUE because satellites visit the site only once or twice a day, near noon. The results showed that (i) the LUE of the alpine meadow generally followed the diurnal and seasonal patterns of solar radiation but fluctuated with changes in cloud cover. (ii) The fraction of diffuse light played a dominant role in LUE variation. Daily minimum temperature and vapor pressure deficit also affected LUE variation. (iii) The adjusted APAR, defined as the weighted linear sum of diffuse APAR and beam APAR, was linearly correlated with GPP on different temporal scales. (iv) Midday adjusted LUE was closely related to daily adjusted LUE, regardless of the cloud cover. The results indicated the importance of considering radiation direction when developing LUE-based GPP-estimating models.
  • Tomomichi Kato, Akihiko Ito, Michio Kawamiya
    CLIMATE DYNAMICS 32 7-8 901 - 923 2009年06月 [査読有り][通常論文]
     
    A coupled climate-carbon cycle model composed of a process-based terrestrial carbon cycle model, Sim-CYCLE, and the CCSR/NIES/FRCGC atmospheric general circulation model was developed. We examined the multiple temporal scale functions of terrestrial ecosystem carbon dynamics induced by human activities and natural processes and evaluated their contribution to fluctuations in the global carbon budget during the twentieth century. Global annual net primary production (NPP) and heterotrophic respiration (HR) increased gradually by 6.7 and 4.7%, respectively, from the 1900s to the 1990s. The difference between NPP and HR was the net carbon uptake by natural ecosystems, which was 0.6 Pg C year(-1) in the 1980s, whereas the carbon emission induced by human land-use changes was 0.5 Pg C year(-1), largely offsetting the natural terrestrial carbon sequestration. Our results indicate that monthly to interannual variation in atmospheric CO2 growth rate anomalies show 2- and 6-month time lags behind anomalies in temperature and the NiNO3 index, respectively. The simulated anomaly amplitude in monthly net carbon flux from terrestrial ecosystems to the atmosphere was much larger than in the prescribed air-to-sea carbon flux. Fluctuations in the global atmospheric CO2 time series were dominated by the activity of terrestrial vegetation. These results suggest that terrestrial ecosystems have acted as a net neutral reservoir for atmospheric CO2 concentrations during the twentieth century on an interdecadal timescale, but as the dominant driver for atmospheric CO2 fluctuations on a monthly to interannual timescale.
  • Makoto Saito, Tomomichi Kato, Yanhong Tang
    GLOBAL CHANGE BIOLOGY 15 1 221 - 228 2009年01月 [査読有り][通常論文]
     
    Alpine ecosystems are extremely vulnerable to climate change. To address the potential variability of the responses of alpine ecosystems to climate change, we examined daily CO2 exchange in relation to major environmental variables. A dataset was obtained from an alpine meadow on the Qinghai-Tibetan Plateau from eddy covariance measurements taken over 3 years (2002-2004). Path analysis showed that soil temperature at 5 cm depth (T-s5) had the greatest effect on daily variation in ecosystem CO2 exchange all year around, whereas photosynthetic photon flux density (PPFD) had a high direct effect on daily variation in CO2 flux during the growing season. The combined effects of temperature and light regimes on net ecosystem CO2 exchange (NEE) could be clearly categorized into three areas depending on the change in T-s5: (1) almost no NEE change irrespective of variations in light and temperature when T-s5 was below 0 degrees C; (2) an NEE increase (i.e. CO2 released from the ecosystem) with increasing T-s5, but little response to variation in light regime when 0 degrees C <= T-s5 <= 8 degrees C; and (3) an NEE decrease with increase in T-s5 and PPFD when T-s5 was approximately > 8 degrees C. The highest daily net ecosystem CO2 uptake was observed under the conditions of daily mean T-s5 of about 15 degrees C and daily mean PPFD of about 50 mol m(-2) day(-1). The results suggested that temperature is the most critical determinant of CO2 exchange in this alpine meadow ecosystem and may play an important role in the ecosystem carbon budget under future global warming conditions.
  • Tomomichi Kato, Yanhong Tang
    GLOBAL CHANGE BIOLOGY 14 10 2333 - 2348 2008年10月 [査読有り][通常論文]
     
    Asian terrestrial ecosystems cover an extensive area characterized by a large variety in climates and ecosystem properties. The observations of ecosystem CO2 flux in this area are increasing both in duration and spatial density, but no synthesis has yet been conducted. We surveyed CO2 flux observation data obtained by eddy covariance methods at 49 sites in terrestrial Asia. The measurements at most sites (44 of 49) began after 2000. The net ecosystem uptake of CO2 (NEE) varied greatly among sites and years and averaged -132.6 +/- 73.7, -250.1 +/- 206.1, and -180.1 +/- 361.7 g C m(-2) yr(-1), in boreal, temperate, and tropical Asia, respectively, and the coefficient of variation among sites increased from boreal to tropical Asia. The site-averaged annual NEE was correlated linearly with the mean annual temperature (T-air) and also correlated logarithmically with the precipitation. Multiple regression analysis and stepwise analysis indicated that photosynthetic active radiation (PAR) and T-air were the most significant predictors of the annual NEE. The study results suggest that Asian terrestrial ecosystems are currently significant net CO2 sinks and that the sink strength is largely controlled by temperature, moisture, and light conditions.
  • Chisato Yoshikawa, Michio Kawamiya, Tomomichi Kato, Yasuhiro Yamanaka, Taroh Matsuno
    Journal of Geophysical Research: Biogeosciences 113 3 2008年09月28日 [査読有り][通常論文]
     
    We examined climate-carbon cycle feedback by performing a global warming experiment using MIROC-based coupled climate-carbon cycle model. The model showed that by the end of the 21st century, warming leads to a further increase in carbon dioxide (CO2) level of 123 ppm by volume (ppmv). This positive feedback can mostly be attributed to land-based soil-carbon dynamics. On a regional scale, Siberia experienced intense positive feedback, because the acceleration of microbial respiration due to warming causes a decrease in the soil carbon level. Amazonia also had positive feedback resulting from accelerated microbial respiration. On the other hand, some regions, such as western and central North America and South Australia, experienced negative feedback, because enhanced litterfall surpassed the increased respiration in soil carbon. The oceanic contribution to the feedback was much weaker than the land contribution on global scale, but the positive feedback in the northern North Atlantic was as strong as those in Amazonia and Siberia in our model. In the northern North Atlantic, the weakening of winter mixing caused a reduction of CO2 absorption at the surface. Moreover, weakening of the formation of North Atlantic Deep Water caused reduced CO2 subduction to the deep water. Understanding such regional-scale differences may help to explain disparities in coupled climate-carbon cycle model results. Copyright 2008 by the American Geophysical Union.
  • A. Ito, J. E. Penner, M. J. Prather, C. P. De Campos, R. A. Houghton, T. Kato, A. K. Jain, X. Yang, G. C. Hurtt, S. Frolking, M. G. Fearon, L. P. Chini, A. Wang, D. T. Price
    Atmospheric Chemistry and Physics 8 12 3291 - 3310 2008年06月18日 [査読有り][通常論文]
     
    The effect of Land Use Change and Forestry (LUCF) on terrestrial carbon fluxes can be regarded as a carbon credit or debit under the UNFCCC, but scientific uncertainty in the estimates for LUCF remains large. Here, we assess the LUCF estimates by examining a variety of models of different types with different land cover change maps in the 1990s. Annual carbon pools and their changes are separated into different components for separate geographical regions, while annual land cover change areas and carbon fluxes are disaggregated into different LUCF activities and the biospheric response due to CO2 fertilization and climate change. We developed a consolidated estimate of the terrestrial carbon fluxes that combines book-keeping models with process-based biogeochemical models and inventory estimates and yields an estimate of the global terrestrial carbon flux that is within the uncertainty range developed in the IPCC 4th Assessment Report. We examined the USA and Brazil as case studies in order to assess the cause of differences from the UNFCCC reported carbon fluxes. Major differences in the litter and soil organic matter components are found for the USA. Differences in Brazil result from assumptions about the LUC for agricultural purposes. The effects of CO 2 fertilization and climate change also vary significantly in Brazil. Our consolidated estimate shows that the small sink in Latin America is within the uncertainty range from inverse models, but that the sink in the USA is significantly smaller than the inverse models estimates. Because there are different sources of errors at the country level, there is no easy reconciliation of different estimates of carbon fluxes at the global level. Clearly, further work is required to develop data sets for historical land cover change areas and models of biogeochemical changes for an accurate representation of carbon uptake or emissions due to LUC.
  • Song Gu, Yanhong Tang, Xiaoyong Cui, Mingyuan Du, Liang Zhao, Yingnian Li, Shixiao Xu, Huakun Zhou, Tomomichi Kato, Peitong Qi, Xinquan Zhao
    Journal of Geophysical Research Atmospheres 113 8 2008年04月 [査読有り][通常論文]
     
    To characterize evapotranspiration (ET) over grasslands on the Qinghai-Tibetan Plateau, we examined ET and its relevant environmental variables in a Kobresia meadow from 2002 to 2004 using the eddy covariance method. The annual precipitation changed greatly, with 554, 706, and 666 mm a-1 for the three consecutive calendar years. The annual ET varied correspondingly to the annual precipitation with 341, 407, and 426 mm a-1. The annual ET was, however, constant at about 60% of the annual precipitation. About 85% annual ET occurred during the growing season from May to September, and the averaged ET for this period was 1.90, 2.23, and 2.22 mm/d, respectively for the three consecutive years. The averaged ET was, however, very low (<0.40 mm/d) during the nongrowing season from October to April. The annual canopy conductance (gc) and the Priestley-Taylor coefficient (α) showed the lowest values in the year with the lowest precipitation. This study first demonstrates that the alpine meadow ecosystem is characterized by a low ratio of annual ET to precipitation and that the interannual variation of ET is determined by annual precipitation. Copyright 2008 by the American Geophysical Union.
  • Xiaoyong Cui, Song Gu, Xinquan Zhao, Jing Wu, Tomomichi Kato, Yanhong Tang
    AGRICULTURAL AND FOREST METEOROLOGY 148 1 144 - 151 2008年01月 [査読有り][通常論文]
     
    We monitored UVA, UVB, and solar radiation from August 2001 to 2003 on the northern Qinghai-Tibetan Plateau to characterize the diurnal and seasonal variations of UV radiation on the world's highest plateau. Daily UVB radiation and the ratio of UVB to total solar radiation increased significantly when the atmospheric ozone concentration decreased as estimated by the total ozone mapping spectrometer (TOMS), as well as when cloud coverage decreased. The UVB/UVA ratio also showed a significant increase when the TOMS ozone concentration decreased in the morning. The seasonal variation pattern of UVB, however, was closely correlated with solar elevation but was little affected by the seasonal pattern of the atmospheric ozone amount. Compared to observations from the central plateau, the magnitude of the UVB increase attributed to ozone depletion was smaller at the northern edge. The study suggests that the temporal variation of ground UV radiation is determined by both solar elevation and the ozone amount, but the spatial difference on the plateau is likely to be ascribed mainly to the spatial variation of the ozone amount. (c) 2007 Published by Elsevier B.V.
  • Mitsuru Hirota, Kiyokazu Kawada, Qiwu Hu, Tomomichi Kato, Yanhong Tang, Wenhong Mo, Guangmin Cao, Shigeru Mariko
    LIMNOLOGY 8 2 161 - 170 2007年08月 [査読有り][通常論文]
     
    To initially describe vegetation structure and spatial variation in plant biomass in a typical alpine wetland of the Qinghai-Tibetan Plateau, net primary productivity and vegetation in relationship to environmental factors were investigated. In 2002, the wetland remained flooded to an average water depth of 25 cm during the growing season, from July to mid-September. We mapped the floodline and vegetation distribution using GPS (global positioning system). Coverage of vegetation in the wetland was 100%, and the vegetation was zonally distributed along a water depth gradient, with three emergent plant zones (Hippuris vulgaris-dominated zone, Scirpus distigmaticus-dominated zone, and Carex allivescers-dominated zone) and one submerged plant zone (Potamogeton pectinatus-dominated zone). Both aboveground and belowground biomass varied temporally within and among the vegetation zones. Further, net primary productivity (NPP) as estimated by peak biomass also differed among the vegetation zones; aboveground NPP was highest in the Carex-dominated zone with shallowest water and lowest in the Potamogeton zone with deepest water. The area occupied by each zone was 73.5% for P. pectinatus, 2.6% for H. vulgaris, 20.5% for S. distigmaticus, and 3.4% for C. allivescers. Morphological features in relationship to gas-transport efficiency of the aerial part differed among the emergent plants. Of the three emergent plants, H. vulgaris, which dominated in the deeper water, showed greater morphological adaptability to deep water than the other two emergent plants.
  • Tomomichi Kato, Yanhong Tang, Song Gu, Mitsuru Hirota, Mingyuan Du, Yingnian Li, Xinquan Zhao
    Global Change Biology 12 7 1285 - 1298 2006年07月 [査読有り][通常論文]
     
    Three years of eddy covariance measurements were used to characterize the seasonal and interannual variability of the CO2 fluxes above an alpine meadow (3250 m a.s.l.) on the Qinghai-Tibetan Plateau, China. This alpine meadow was a weak sink for atmospheric CO2, with a net ecosystem production (NEP) of 78.5, 91.7, and 192.5 g C m-2 yr-1 in 2002, 2003, and 2004, respectively. The prominent, high NEP in 2004 resulted from the combination of high gross primary production (GPP) and low ecosystem respiration (Re) during the growing season. The period of net absorption of CO2 in 2004, 179 days, was 10 days longer than that in 2002 and 5 days longer than that in 2003. Moreover, the date on which the mean air temperature first exceeded 5.0°C was 10 days earlier in 2004 (DOY110) than in 2002 or 2003. This date agrees well with that on which the green aboveground biomass (Green AGB) started to increase. The relationship between light-use efficiency and Green AGB was similar among the three years. In 2002, however, earlier senescence possibly caused low autumn GPP, and thus the annual NEP, to be lower. The low summertime Re in 2004 was apparently caused by lower soil temperatures and the relatively lower temperature dependence of Re in comparison with the other years. These results suggest that (1) the Qinghai-Tibetan Plateau plays a potentially significant role in global carbon sequestration, because alpine meadow covers about one-third of this vast plateau, and (2) the annual NEP in the alpine meadow was comprehensively controlled by the temperature environment, including its effect on biomass growth. © 2006 Blackwell Publishing Ltd.
  • P. Friedlingstein, P. Cox, R. Betts, L. Bopp, W. Von Bloh, V. Brovkin, P. Cadule, S. Doney, M. Eby, I. Fung, G. Bala, J. John, C. Jones, F. Joos, T. Kato, M. Kawamiya, W. Knorr, K. Lindsay, H. D. Matthews, T. Raddatz, P. Rayner, C. Reick, E. Roeckner, K. -G. Schnitzler, R. Schnur, K. Strassmann, A. J. Weaver, C. Yoshikawa, N. Zeng
    JOURNAL OF CLIMATE 19 14 3337 - 3353 2006年07月 [査読有り][通常論文]
     
    Eleven coupled climate-carbon cycle models used a common protocol to study the coupling between climate change and the carbon cycle. The models were forced by historical emissions and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 anthropogenic emissions of CO2 for the 1850-2100 time period. For each model, two simulations were performed in order to isolate the impact of climate change on the land and ocean carbon cycle, and therefore the climate feedback on the atmospheric CO2 concentration growth rate. There was unanimous agreement among the models that future climate change will reduce the efficiency of the earth system to absorb the anthropogenic carbon perturbation. A larger fraction of anthropogenic CO2 will stay airborne if climate change is accounted for. By the end of the twenty-first century, this additional CO2 varied between 20 and 200 ppm for the two extreme models, the majority of the models lying between 50 and 100 ppm. The higher CO2 levels led to an additional climate warming ranging between 0.1 degrees and 1.5 degrees C. All models simulated a negative sensitivity for both the land and the ocean carbon cycle to future climate. However, there was still a large uncertainty on the magnitude of these sensitivities. Eight models attributed most of the changes to the land, while three attributed it to the ocean. Also, a majority of the models located the reduction of land carbon uptake in the Tropics. However, the attribution of the land sensitivity to changes in net primary productivity versus changes in respiration is still subject to debate; no consensus emerged among the models.
  • Mitsuru Hirota, Yanhong Tang, Qiwu Hu, Shigeki Hirata, Tomomichi Kato, Wenhong Mo, Guangmin Cao, Shigeru Mariko
    ECOSYSTEMS 9 4 673 - 688 2006年06月 [査読有り][通常論文]
     
    To initially characterize the dynamics and environmental controls of CO2, ecosystem CO2 fluxes were measured for different vegetation zones in a deep-water wetland on the Qinghai-Tibetan Plateau during the growing season of 2002. Four zones of vegetation along a gradient from shallow to deep water were dominated, respectively by the emergent species Carex allivescens V. Krez., Scirpus distigmaticus L., Hippuris vulgaris L., and the submerged species Potamogeton pectinatus L. Gross primary production (GPP), ecosystem respiration (Re), and net ecosystem production (NEP) were markedly different among the vegetation zones, with lower Re and GPP in deeper water. NEP was highest in the Scirpus-dominated zone with moderate water depth, but lowest in the Potamogeton-zone that occupied approximately 75% of the total wetland area. Diurnal variation in CO2 flux was highly correlated with variation in light intensity and soil temperature. The relationship between CO2 flux and these environmental variables varied among the vegetation zones. Seasonal CO2 fluxes, including GPP, Re, and NEP, were strongly correlated with aboveground biomass, which was in turn determined by water depth. In the early growing season, temperature sensitivity (Q(10)) for Re varied from 6.0 to 8.9 depending on vegetation zone. Q(10) decreased in the late growing season. Estimated NEP for the whole deep-water wetland over the growing season was 24 g C m(-2). Our results suggest that water depth is the major environmental control of seasonal variation in CO2 flux, whereas photosynthetic photon flux density (PPFD) controls diurnal dynamics.
  • T Kato, M Kamichika
    IRRIGATION AND DRAINAGE 55 2 165 - 175 2006年04月 [査読有り][通常論文]
     
    The FAO basal crop coefficient K-cb and the soil evaporation coefficient K-e for a sparse sorghum field in one growing season were estimated using the compartment model (Shuttleworth-Wallace model; S-W model), which separately estimates transpiration from crops and evaporation from the soil. The Kcb had a low value Of 0-10 (K-cb,K- ini) during the initial period, increased rapidly to a maximum of 0.98 (K-cb, (mid)) at midseason, and decreased rapidly to 0.53 (K-cb, (end)) by the end of the growing season. The Kcb increased with increasing leaf area index (LAI) rapidly and slowly, respectively, below and above an LAI of 1.0. The K, showed a positive relationship to increasing soil water content (SWC) at a depth of -15.0cm, but the soil water content indicated a negative relationship to increasing LAI. Using the dual crop coefficients derived by their relationships to the LAI and soil water content, the actual evapotranspiration (ETa) was estimated and compared to the ETa derived by the Bowen ratio energy budget (BREB) method. The root mean square error (RMSE) of the ETa obtained from the simulated crop coefficient to the ET. obtained by the BREB method was 0.84 mm day(-1). Thus, the adjusted relationship of Kb and K-e allowed a good estimation of the evapotranspiration in an irrigated field with sparse vegetation cover. Copyright (c) 2006 John Wiley & Sons, Ltd.
  • T Kato, M Hirota, YH Tang, XY Cui, YN Li, XQ Zhao, T Oikawa
    SOIL BIOLOGY & BIOCHEMISTRY 37 10 1966 - 1969 2005年10月 [査読有り][通常論文]
     
    We examined the CO2 exchange of a Kobresia meadow ecosystem on the Qinghai-Tibetan plateau using a chamber system. CO2 efflux from the ecosystem was strongly dependence on soil surface temperature. The COZ efflux-temperature relationship was identical under both light and dark conditions, indicating that no photosynthesis could be detected under light conditions during the measurement period. The temperature sensitivity (Q(10)) of the COZ efflux showed a marked transition around -1.0 degrees C; Q(10) was 2.14 at soil surface temperatures above and equal to -1.0 degrees C but was 15.3 at temperatures below -1.0 degrees C. Our findings suggest that soil surface temperature was the major factor controlling winter COZ flux for the alpine meadow ecosystem and that freeze-thaw cycles at the soil surface layer play an important role in the temperature dependence of winter CO2 flux. (c) 2005 Elsevier Ltd. All rights reserved.
  • M Hirota, YH Tang, QW Hu, T Kato, S Hirata, WH Mo, GM Cao, S Mariko
    ATMOSPHERIC ENVIRONMENT 39 29 5255 - 5259 2005年09月 [査読有り][通常論文]
     
    To assess the impact of livestock grazing on the emission of greenhouse gases from grazed wetlands, we examined biomass growth of plants, CO2 and CH4 fluxes under grazing and non-grazing conditions on the Qinghai-Tibetan Plateau wetland. After the grazing treatment for a period of about 3 months, net ecosystem CO2 uptake and aboveground biomass were significantly smaller, but ecosystem CH4 emissions were remarkably greater, under grazing conditions than under non-grazing conditions. Examination of the gas-transport system showed that the increased CH4 emissions resulted from mainly the increase of conductance in the gas-transport system of the grazed plants. The sum of global warming potential, which was estimated from the measured CO2 and CH4 fluxes, was 5.6- to 11.3-fold higher under grazing conditions than under non-grazing conditions. The results suggest that livestock grazing may increase the global warming potential of the alpine wetlands. (c) 2005 Elsevier Ltd. All rights reserved.
  • Song Gu, Yanhong Tang, Xiaoyong Cui, Tomomichi Kato, Mingyuan Du, Yingnian Li, Xinquan Zhao
    Agricultural and Forest Meteorology 129 3-4 175 - 185 2005年04月 [査読有り][通常論文]
     
    To reveal the potential contribution of grassland ecosystems to climate change, we examined the energy exchange over an alpine Kobresia meadow on the northeastern Qinghai-Tibetan Plateau. The annual pattern of energy exchange showed a clear distinction between periods of frozen soil with the daily mean soil temperature at 5 cm (Ts5 ≤ 0°C) and non-frozen soil (Ts5 >0°C). More than 80% of net radiation was converted to sensible heat (H) during the frozen soil period, but H varied considerably with the change in vegetation during the non-frozen soil period. Three different sub-periods were further distinguished for the later period: (1) the pre-growth period with Bowen ratio (β) > 1 was characterized by a high β of 3.0 in average and the rapid increase of net radiation associated with the increases of H, latent heat (LE) and soil heat; (2) during the growth period when β ≤ 1, the LE was high but H fluxes was low with β changing between 0.3 and 0.4; (3) the post-growth period with average β of 3.6 when H increased again and reached a second maximum around early October. The seasonal pattern suggests that the phenology of the vegetation and the soil water content were the major factors affecting the energy partitioning in the alpine meadow ecosystem. © 2005 Elsevier B.V. All rights reserved.
  • JY Fang, T Oikawa, T Kato, WH Mo, ZH Wang
    GLOBAL BIOGEOCHEMICAL CYCLES 19 2 1 - 10 2005年04月 [査読有り][通常論文]
     
    Forest ecosystems in the Northern Hemisphere function as carbon (C) sinks for atmospheric carbon dioxide; however, the magnitude, location, and cause of the sinks remain uncertain. A number of field measurements of forest biomass and systematic national forest inventories in Japan make it possible to quantify the C sinks and their distribution. Allometric relationships between forest biomass and stem volume were obtained for the major forest types in Japan from 945 sets of direct field measurements across the country. These relationships were used to estimate the changes in C accumulations of aboveground biomass and total living biomass from 1947 to 1995 from the national forest inventories of 1947, 1956, 1961, 1965, 1975, 1980, 1985, 1990, and 1995. The results showed that the C accumulations have significantly increased during the last 50 years. The C density ( C stock per hectare) and total C stock of aboveground biomass increased from 27.6 Mg C/ha and 611.7 Tg C in 1947 to 43.2 Mg C/ha and 1027.7 Tg C in 1995, respectively, and those of total living biomass increased from 33.9 Mg C/ha and 751.8 Tg C in 1947 to 53.6 Mg C/ha and 1274.8 Tg C in 1995. These increases were remarkable during 1976-1995, with a net increase of 5.6 Mg C/ha and 369 Tg C for the C density and total living biomass. These results suggest that Japan's forest vegetation is a significant C sink. In the past 20 years, living vegetation has sequestered 18.5 Tg C annually, 14.6 Tg C of which was accumulated in aboveground biomass. The total C sink for the whole forest sector (including nonliving biomass) of Japan was estimated as 36 Tg C/yr if using the net change ratio of nonliving biomass C to living biomass C derived from the United States and Europe. On the basis of average C sink per hectare, Japan's forests have a higher sequestration rate (0.77 Mg C ha(-1) yr(-1)) than the average of the other northern countries (0.14-0.19 Mg C ha(-1) yr(-1)). The expansion and regrowth of planted forests are two major causes for this increased C uptake; planted forests contribute similar to 80% of the total C sink in Japan. The suitable oceanic climate for fast forest growth and effective forest management practice may be the principal factors for such a large sink.
  • Tomomichi Kato, Yanhong Tang, Song Gu, Xiaoyong Cui, Mitsuru Hirota, Mingyuan Du, Yingnian Li, Xingquan Zhao, Takehisa Oikawa
    Agricultural and Forest Meteorology 124 1-2 121 - 134 2004年07月20日 [査読有り][通常論文]
     
    We used the eddy covariance method to measure the CO2 exchange between the atmosphere and an alpine meadow ecosystem (37°29-45′N, 101°12-23′E, 3250 m a.s.l.) on the Qinghai-Tibetan Plateau, China in the 2001 and 2002 growing seasons. The maximum rates of CO2 uptake and release derived from the diurnal course of CO2 flux (F CO2) were -10.8 and 4.4 μmol m-2 s-1, respectively, indicating a relatively high net carbon sequestration potential as compared to subalpine coniferous forest at similar elevation and latitude. The largest daily CO2 uptake was 3.9 g C m-2 per day on 7 July 2002, which is less than half of those reported for lowland grassland and forest at similar latitudes. The daily CO2 uptake during the measurement period indicated that the alpine ecosystem might behave as a sink of atmospheric CO2 during the growing season if the carbon lost due to grazing is not significant. The daytime CO2 uptake was linearly correlated with the daily photosynthetic photon flux density each month. The nighttime averaged FCO2 showed a positive exponential correlation with the soil temperature, but apparently negative correlation with the soil water content. © 2004 Elsevier B.V. All rights reserved.
  • Tomomichi Kato, Yanhong Tang, Song Gu, Mitsuru Hirota, Xiaoyong Cui, Mingyuan Du, Yingnian Li, Xinquan Zhao, Takehisa Oikawa
    Journal of Geophysical Research D: Atmospheres 109 12 2004年06月27日 [査読有り][通常論文]
     
    We measured the net ecosystem CO2 exchange (NEE) in an alpine meadow ecosystem (latitude 37°29′-45′N, longitude 101°12′-23′E, 3250 m above sea level) on the Qinghai-Tibetan Plateau throughout 2002 by the eddy covariance method to examine the carbon dynamics and budget on this unique plateau. Diurnal changes in gross primary production (GPP) and ecosystem respiration (Re) showed that an afternoon increase of NEE was highly associated with an increase of Re. Seasonal changes in GPP corresponded well to changes in the leaf area index and daily photosynthetic photon flux density. The ratio of GPP/Re was high and reached about 2.0 during the peak growing season, which indicates that mainly autotrophic respiration controlled the carbon dynamics of the ecosystem. Seasonal changes in mean GPP and Re showed compensatory behavior as reported for temperate and Mediterranean ecosystems, but those of GPPmax and Remax were poorly synchronized. The alpine ecosystem exhibited lower GPP (575 g C m-2 y-1) than, but net ecosystem production (78.5 g C m-2 Y-1) similar to, that of subalpine forest ecosystems. The results suggest that the alpine meadow behaved as a CO2 sink during the 1-year measurement period but apparently sequestered a rather small amount of C in comparison with similar alpine ecosystems. Copyright 2004 by the American Geophysical Union.
  • M Hirota, YH Tang, QW Hu, S Hirata, T Kato, WH Mo, GM Cao, S Mariko
    SOIL BIOLOGY & BIOCHEMISTRY 36 5 737 - 748 2004年05月 [査読有り][通常論文]
     
    We measured methane (CH4) emissions in the Luanhaizi wetland, a typical alpine wetland on the Qinghai-Tibetan Plateau, China, during the plant growth season (early July to mid-September) in 2002. Our aim was to quantify the spatial and temporal variation of CH4 flux and to elucidate key factors in this variation. Static chamber measurements of CH4 flux were made in four vegetation zones along a gradient of water depth. There were three emergent-plant zones (Hippuris-dominated; Scirpus-dominated; and Carex-dominated) and one submerged-plant zone (Potamogeton-dominated). The smallest CH4 flux (seasonal mean = 33.1 mg CH4 m(-2) d(-1)) was, observed in the Potamogeton-dominated zone, which occupied about 74% of the total area of the wetland. The greatest CH4 flux (seasonal mean = 214 mg CH4 m(-2) d(-1)) was observed in the Hippuris-dominated zone, in the second-deepest water area. CH4 flux from three zones (excluding the Carex-dominated zone) showed a marked diurnal change and decreased dramatically under dark conditions. Light intensity had a major influence on the temporal variation in CH4 flux, at least in three of the zones. Methane fluxes from all zones increased during the growing season with increasing aboveground biomass. CH4 flux from the Scirpus-dominated zone was significantly lower than in the other emergent-plant zones despite the large biomass, because the root and rhizome intake ports for CH4 transport in the dominant species were distributed in shallower and more oxidative soil than occupied in the other zones. Spatial and temporal variation in CH4 flux from the alpine wetland was determined by the vegetation zone. Among the dominant species in each zone, there were variations in the density and biomass of shoots, gas-transport system, and root-rhizome architecture. The CH4 flux from a typical alpine wetland on the Qinghai-Tibetan Plateau was as high as those of other boreal and alpine wetlands. (C) 2004 Elsevier Ltd. All rights reserved.
  • T Kato, R Kimura, M Kamichika
    AGRICULTURAL WATER MANAGEMENT 65 3 173 - 191 2004年03月 [査読有り][通常論文]
     
    Using the Shuttleworth and Wallace (S-W) model, evapotranspiration (ET); transpiration ratio (PET), which is the ratio of transpiration (T) to ET; and water-use efficiency (WUE) were estimated for a sparsely planted sorghum canopy that was well irrigated. That model is designed to estimate separately the evaporation from soil and transpiration from crops. The evapotranspiration estimates for both short- and long-term measurement periods coincided closely with the Bowen ratio energy balance (BREB) measurements. The transpiration ratios were affected by the canopy resistances and the soil surface resistances during the day. The regression curve between leaf area index (LAI) and transpiration ratio suggests that LAI, less than 1.6, determined the transpiration ratio in the absence of water stresses by soil water drought and extreme weather condition. The WUEs for transpiration (WUEt) and evapotranspiration (WUEet), which are the total dry matter (TDM) production for 1 kg T and ET, reached the peaks of 9.0 and 4.5 g kg(-1) H2O, respectively, in the end of July when the total dry matter increasing rate was greatest. These two WUEs degraded to less than zero in the end of August when the plant biomass decreased due to drying and death. The WUEs are largely affected by the TDM seasonal increment rate. Thus, in a sparse crop, the crop growth properties (i.e. LAI and TDM increment) mainly determine the crop water uses (i.e. the transpiration ratio and water-use efficiency) in the absence of water stresses. (C) 2003 Elsevier B.V. All rights reserved.
  • Song Gu, Yanhong Tang, Mingyuan Du, Tomomichi Kato, Yingnian Li, Xiaoyong Cui, Xingquan Zhao
    Journal of Geophysical Research D: Atmospheres 108 21 2003年11月16日 [査読有り][通常論文]
     
    The alpine meadow ecosystem on the Qinghai-Tibetan Plateau may play a significant role in the regional carbon cycle. To assess the CO2 flux and its relationship to environmental controls in the ecosystem, eddy covariance of CO2, H2O, and energy fluxes was measured with an open-path system in an alpine meadow on the plateau at an elevation of 3,250 m. Net ecosystem CO2 influx (Fc) averaged 8.8 g m-2 day-1 during the period from August 9 to 31, 2001, with a maximum of 15.9 g m-2 day-1 and a minimum of 2.3 g m-2 day-1. Daytime Fc averaged 16.7 g m-2 day-1 and ranged from 10.4 g m-2 day-1 to 21.7 g m-2 day-1 during the study period. For the same photosynthetic photon flux density (PPFD), gross CO2 uptake (Gc) was significantly higher on cloudy days than on clear days. However, mean daily Gc was higher on clear days than on cloudy days. With high PPFD, Fc decreased as air temperature increased from 10°C to 23°C. The greater the difference between daytime and nighttime air temperatures, the more the sink was strengthened. Daytime average water use efficiency of the ecosystem (WUEe) was 8.7 mg (CO2 (g H2O)-1; WUEe values ranged from 5.8 to 15.3 mg (CO2)(g H2O)-1 WUEe increased with the decrease in vapor pressure deficit. Daily albedo averaged 0.20, ranging from 0.19 to 0.22 during the study period, and was negatively correlated with daily Fc. Our measurements provided some of the first evidence on CO2 exchange for a temperate alpine meadow ecosystem on the Qinghai-Tibetan Plateau, which is necessary for assessing the carbon budget and carbon cycle processes for temperate grassland ecosystems. Copyright 2003 by the American Geophysical Union.

書籍

  • アグリバイオ 2022年2月号 農業気象学研究の最前線
    加藤知道 (担当:分担執筆範囲:地球環境保全に向けた農業気象学の展開)
    北隆館 2022年02月
  • 農業気象学入門(鮫島良次編)
    加藤知道 (担当:分担執筆範囲:第8章, 気象データと気象観測)
    文永堂出版 2020年12月
  • 加藤 知道 (担当:編者(編著者)範囲:監訳)
    森北出版 2018年07月 (ISBN: 9784627261228) 595p, 図版8p 
    生態系レベルの大きな空間スケールで、現象を理解する。個体や群集スケールの生物学・生理学的な視点と、グローバルスケールの地球システム科学の視点をつなぐ、世界的名著の邦訳。
  • 植物と微気象(第3版)-植物生理生態学への定量的なアプローチ
    加藤 知道 (担当:共著範囲:第12章 生理学と作物収量の改善)
    森北出版 2017年02月
  • Frontiers of Agricultural Science
    加藤 知道 (担当:共著範囲:Chapter 1.2. Carbon cycle)
    Hokkaido University 2015年
  • シリーズ現代の生態学, 第2巻「地球環境変動の生態学」
    加藤 知道 (担当:共著範囲:第一章, 地球環境変動と陸域生態系;第二章, 陸域生態系研究における現地観測)
    共立出版 2014年

作品等

  • 中国青海省のチベット高原にて炭素循環の調査
    2001年08月

その他活動・業績

特許

  • 特許第6725154号:クロロフィル蛍光測定装置  
    加藤 知道  国立大学法人北海道大学

受賞

  • 2017年02月 コニカミノルタ科学技術振興財団 コニカミノルタ画像科学奨励賞
     
    受賞者: 加藤 知道
  • 2005年09月 農業環境工学関連7学会2005年度合同大会 ベストポスター賞
     
    受賞者: 加藤 知道

共同研究・競争的資金等の研究課題

  • 熱帯林における太陽光誘起クロロフィル蛍光による光合成量の観測とモデル化
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2022年04月 -2026年03月 
    代表者 : 加藤 知道, 宮内 達也, 彦坂 幸毅, 小林 秀樹, 中路 達郎, 野田 響, 冨松 元, 小杉 緑子
  • 統合生物圏科学の構築にかかる支援活動
    日本学術振興会:科学研究費助成事業 学術変革領域研究(A)
    研究期間 : 2021年09月 -2026年03月 
    代表者 : 伊藤 昭彦, 彦坂 幸毅, 小林 秀樹, 村岡 裕由, 近藤 倫生, 安立 美奈子, 熊谷 朝臣, 平舘 俊太郎, 加藤 知道, 植山 雅仁, 日浦 勉, 小野田 雄介
  • 地球システムモデルによる生態系環境適応が気候へ与えるフィードバックの解明
    日本学術振興会:科学研究費助成事業 学術変革領域研究(A)
    研究期間 : 2021年09月 -2026年03月 
    代表者 : 加藤 知道, 立入 郁, 羽島 知洋, 相田 真希
  • アジアの歴史的な気候変動がコメ収量に与えた影響の水稲生育モデルによる定量
    日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2022年06月 -2025年03月 
    代表者 : 加藤 知道, 増冨 祐司
  • シベリア森林火災が炭素循環・植生分布・エアロゾル放出に与える影響のモデル推定
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : DELBART Nicolas, 小林 秀樹, 加藤 知道, 酒井 佑槙
     
    SEIB-DGVMによるシベリア全域(北緯50-70度、東経60-150度)の現在気候データによるテストランを行なった。入力にはCRUおよびNCEP/NCAR気候データを利用し、炭素蓄積量を平衡させるためのスピンアップ(1000年間:1901-1930年の気候データを繰り返し与える)行い、モデルが現在(1990-2017)において正常に稼働することを確認した。また、火災モジュールを作るための各種衛星データ等(土壌水分(SMOS, 9km x 9km, 3時間ステップ, NASA)、落雷(OTD, 0.5o x 0.5o, 年平均, NASA)、気候(CRU TS 4.01, 0.5o x 0.5o, 月ステップ)、人口分布(GPW, 0.25o x 0.25o, NASA))も入手し、0.5o x 0.5o, 月ステップのグリッド化されたフォーマットに統一加工した。消失バイオマスあたりに放出されるエアロゾル量については、火災エアロゾル放出係数(Akagi et al., 2011, ACPなど)をもとに、SEIB-DGVMの火災モジュールに追加する形でプログラムを変更している。 火災発生の推定精度が森林生態系の炭素収支に与える影響をあらかじめ把握するために、火災発生確率を1倍、10倍、50倍に変化させて、濃度経路シナリオ(RCP)2.6および8.5による将来気候データを利用しシミュレーションを行なったところ、確率が増加するにしたがって、現在と比べて将来(2071-2100年)に総一次生産、純一次生産、および森林バイオマス量が著しく低下することがわかった。
  • 対流圏オゾンがコムギ生産量に与える影響のプロセスモデルによる将来予測
    日立財団:倉田奨励金
    研究期間 : 2022年04月 -2023年03月 
    代表者 : 加藤知道, 増冨 祐司
  • 若齢森林の太陽光誘起クロロフィル蛍光を用いた光合成量の実時間推定法
    島津科学技術振興財団:研究開発助成金
    研究期間 : 2022年04月 -2023年03月 
    代表者 : 加藤知道, 高木健太郎
  • 人工衛星データを利用した我が国の森林炭素蓄積量を推定するための機械学習モデル開発
    公益財団法人電気通信普及財団:研究調査助成
    研究期間 : 2021年04月 -2023年03月 
    代表者 : 加藤 知道
  • 炭素飢餓がグローバルな森林CO2吸収量に与える影響の定量化
    日本生命財団:環境問題研究助成
    研究期間 : 2021年10月 -2022年09月 
    代表者 : 加藤知道
  • 近世における気候変動がコメ収量に及ぼした影響の定量的解明
    日本学術振興会:科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2019年06月 -2022年03月 
    代表者 : 加藤 知道, 増冨 祐司
     
    昨年度デジタル化した稲刈帳からの玄米重量を解析したところ、収量の長期トレンドは、ほとんどの場所にて上昇を示していた。一方で、微小変化成分は特に天保の大飢饉とされる期間(1832-1839年)において、東日本の地点では大きく負の値を取っていた。さらに、古くにデータが存在している山形・山梨では天明の大飢饉があったとされる期間(1783-1786年)においても、収量が大きく低下する年が見られた。しかし、主に西日本で被害があったとされる享保年間には、山形のデータしか残っていなかったために、明瞭は収量の低下は見られなかった。 復元気候データ(樹木年輪より復元した夏季気温データとエルニーニョ・南方振動指数)との水稲収量の変動成分は、すべての地点で相関を示さなかった(相関係数が全ての地点と復元気候データの間で0.01以下)。これは水稲収量が地形などによる微気象変動から影響を受けているが、対比に利用した年輪解析の気候データは、多数の観測データを平均しているために、微気象を反映できていないことから来ていると思われる。また、エルニーニョ・南方振動指数は、北米の年輪データを元にしていることや、エルニーニョ現象よりもPDOなどのより日本付近の気候モードに支配されていることを示唆している。 水稲生育モデルMATCRO-Riceを利用するための、入力気候データを米国大気海洋局20世紀再解析データ(NOAA-CIRES-20CRV3, T254, 512x256グリッド, 3時間ステップ, 1806-2015年)より準備を進めた。空間解像度を0.5°x0.5°(720x360グリッド)に、時間ステップを1日に変更した。長期ランの実行時間を削減するために、モデルの動作時間ステップをオリジナルの3時間から1日へプログラム改変している。またオリジナルモデルによって、茨城県を対象にしたテストランを行なった。
  • フィールド科学の明日を切り開く先端・応用予測研究
    北海道大学 創成研究機構:創成特定研究事業
    研究期間 : 2020年10月 -2022年03月 
    代表者 : 見延庄士郎, 稲津 將, 佐々木 克徳, 加藤 知道, 上野 洋路, 小山 聡
  • GOSAT-2による太陽光誘起クロロフィル蛍光を利用した生態系光合成量推定の高精度化
    環境省:環境研究総合推進費・低炭素領域・環境問題対応研究
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 加藤 知道, 彦坂 幸毅, 小林 秀樹, 中路 達郎, 小杉 緑子, 松本 一穂
  • アジアにおける歴史的統計資料を利用した気候変動が水稲生産力に及ぼした影響の解明
    村田学術財団:研究助成(人文科学)
    研究期間 : 2020年12月 -2021年11月 
    代表者 : 加藤 知道
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2018年04月 -2021年03月 
    代表者 : 加藤 知道, 彦坂 幸毅, 小林 秀樹, 市井 和仁, 野田 響
     
    陸域生態系の光合成量の把握は、CO2吸収による気候変動緩和効果の見積もりのために非常に重要である。新しい植生リモートセンシング指標である太陽光誘起クロロフィル蛍光(SIF)は広域・リアルタイムな生態系光合成量の推定に非常に役立つと期待されており、SIFの利用可能性を向上させるため、個葉-生態系スケールの観測と3次元放射伝達モデルの開発・検証を行った。その結果、SIFの光等の環境要因による挙動を明らかにし、さらにそれらを元にした生態系光合成量の推定について、高低解像度システムの協働による新しいアプローチの提案と、それらを再現する3次元放射伝達モデルの開発に成功した。
  • グローバルな太陽光誘起クロロフィル蛍光の地上観測・モデル・衛星の相互比較
    日本学術振興会:科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(A))
    研究期間 : 2019年04月 -2021年 
    代表者 : 加藤 知道
     
    高波長分解能分光放射計によるSIF地上観測のための機器設置・管理・データ処理のプロトコルを確率した。また複数のサイトにおいて、地上観測SIFと渦相関法から得られた総一次生産(GPP)との関係を調べた。水田・湿地サイトでは、赤領域SIF(O2Bバンド)・近赤外領域SIF(O2Aバンド)が共にGPPとの間で強い線形の相関を示した。また落葉広葉林サイトでは、林内の複数高度における上下方向のSIFの推定を行い、GPPとの間で正の相関があることがわかり、SIFによるGPPの再現可能性が高いことがわかった。亜熱帯サイトにおいては2020年度に1シーズン分のSIFを安定して観測することができ、現在は渦相関法GPPとの比較を進めている。さらに複数サイトの2019-2020年における地上観測SIFによる衛星観測SIFの検証と、SIF-GPP関係について、サイト間比較を進めている。中分解能分光放射計データに新たに開発したaFLD法を利用し、落葉広葉樹林サイトの11年間の長期SIFデータを推定した(Nakashima et al., 2021, 修正中)。開発が終了し投稿したFLiES-SIFのモデル記述論文については、2020年度に査読者の指摘をもとに既存モデルとの比較などの追加実験を実施し論文成果として公表することができた。三次元森林放射伝達モデルFLiES-SIFを利用し、札幌市のコムギ畑において観測されたSIFの日中低下が、条立て方位によって発生することを明らかにした。
  • 稲刈帳による近世のコメ収量復元およびその気候変動との関係の解明
    三菱財団:人文科学研究助成
    研究期間 : 2019年10月 -2020年09月 
    代表者 : 加藤 知道
  • 野外におけるコムギ光合成活性の遠隔推定手法の開発
    北海道大学:ロバスト農林水産工学研究プログラム
    研究期間 : 2019年05月 -2020年03月 
    代表者 : 加藤 知道
  • 太陽光誘発クロロフィル蛍光による湿地生態系のCO2吸収量の解明
    住友財団:環境研究助成
    研究期間 : 2018年10月 -2019年10月 
    代表者 : 加藤 知道, 平野 高司, 植山 雅仁
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 小林 秀樹, 近藤 雅征, 市井 和仁, 加藤 知道, 野田 響, 楊 偉, 林 真智
     
    陸域植生の光合成は陸域生物圏の炭素循環の最も大きなフラックスであるが全球の光合成量推定値にはなお大きな不確実性がある。近年、地球観測衛星で得られる光合成活性指標としてクロロフィル蛍光(Sun Induced Fluorescence, SIF)が注目され、生態系モデルによる全球光合成量推定値の検証・制約データとして利用されつつある。本研究では衛星観測によるSIFデータから光合成活性指標を推定するために必要となる高精度なSIF放射のシミュレーションモデルを開発し、開発したモデルを日本やアラスカの森林での観測データと比較して性能を評価した。
  • コムギ光合成活性のリアルタイム野外計測システムの開発
    エリザベス・アーノルド富士財団:
    研究期間 : 2018年07月 -2019年03月 
    代表者 : 加藤 知道
  • 太陽光誘発クロロフィル蛍光による生態系光合成量推定のための包括的モデルの構築
    環境省:環境研究総合推進費・脱温暖化社会部会・革新型研究開発領域
    研究期間 : 2016年06月 -2019年03月 
    代表者 : 加藤 知道, 小林 秀樹
  • 森林によるCO2吸収量計測のためのクロロフィル蛍光センサーの開発
    JFE21世紀財団:
    研究期間 : 2018年01月 -2018年12月 
    代表者 : 加藤 知道
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2015年07月 -2018年03月 
    代表者 : 加藤 知道, 齋藤 陽子, 増冨 祐司, 増冨 祐司
     
    人口急増とともに食料増産の要求が年々高まっている。一方で、将来の気候変動は農業生産に大きな影響を与えると予測される(IPCC, 2014)。その影響を調べることは我が国の食料確保だけでなく安全保障の上でも非常に重要である。そこで過去約110年間(1901-2012)の県別の水稲についての農業統計資料、農業試験場の栽培試験結果、作物収量モデルシミュレーション、再解析気候データを組み合わせ、気候変動が水稲収量に及ぼした影響の統合的な解析を行った。
  • 日本学術振興会:科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 加藤 知道
     
    森林などの生態系は光合成により、温室効果ガスであるCO2を大気から吸収しており、その量を正確に把握することは、将来の地球の気候変化を予測する上で非常に重要である。その光合成は太陽光を利用するが、利用されなかった光エネルギーの一部(2%まで)は、クロロフィル蛍光として放出される。本研究では、光合成の直接的な指標であり、非接触で測定可能な太陽光誘発クロロフィル蛍光(SIF)を新たに活用し、岐阜県高山市の落葉広葉樹林の光合成量の空間分布を明らかにすることを目的とし、既存分光放射データによる鉛直方向の分割観測と、新規の高精度分光放射計による鉛直分布観測を行った。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2014年04月 -2018年03月 
    代表者 : 村岡 裕由, 村山 昌平, 中路 達郎, 斎藤 琢, 野田 響, 永井 信, 魯 南賑, 栗林 正俊, 伊藤 昭彦, 加藤 知道
     
    森林生態系の炭素循環や炭素固定機能を決める生態系呼吸の動態メカニズムと林冠光合成の関係を,生態系生理学的手法と大気化学的手法,モデル解析によって解明し,森林生態系機能の変動予測研究を進めることを目的とした。冷温帯地域の落葉広葉樹林や常緑針葉樹林では,温暖化が光合成量と生態系呼吸量の季節性や収支に顕著な影響を及ぼすことが,個葉光合成能の現地観測,樹木と土壌の温暖化実験,複数のモデルシミュレーションによって解明された。
  • 持続的農業につながる作物光合成活性のリアルタイムモニタリングカメラの開発
    ヤンマー資源循環支援機構:助成事業
    研究期間 : 2017年04月 -2018年03月 
    代表者 : 加藤 知道
  • 光合成機能の野外における面的リアルタイム把握のためのSIF計測カメラの開発
    コニカミノルタ科学技術振興財団:画像科学奨励賞
    研究期間 : 2017年04月 -2018年03月 
    代表者 : 加藤 知道
  • 生態系の生育状況を面的に測る光合成カメラの開発
    八洲環境技術振興財団:基礎試験研究・調査に対する助成
    研究期間 : 2016年04月 -2017年03月 
    代表者 : 加藤 知道
  • 野外における生態系光合成量推定のためのクロロフィル蛍光センサーの開発
    栗林育英学術財団:個人研究
    研究期間 : 2015年09月 -2017年03月 
    代表者 : 加藤 知道
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 市井 和仁, 小林 秀樹, 佐藤 永, 加藤 知道, 植山 雅仁, 佐々井 崇博, 近藤 雅征, 渡邊 明, 伊藤 昭彦, 三枝 信子, 平野 高司
     
    AsiaFluxに代表される地上観測データと様々な衛星データと複数の陸域生態系モデルを用いて、モデル・データ相互比較実験を行うことで、アジア域における陸域炭素収支の変動を定量化し、その変動要因を解析した。まず、AsiaFluxデータ等のデータと衛星データを利用した経験モデルを構築し、アジア域のCO2フラックスを2000-2015年の期間で推定した。更に共通の実験設定下で複数の陸域炭素循環モデルを動作させ、様々なデータと比較した。シベリア域では経験モデルとのCO2収支推定結果と一貫性が高いことを示した。一方で、熱帯域についてはモデル間の違いや経験モデルとの違いが大きく、今後の課題として残された。
  • 我が国の作物生産性の歴史に学ぶ気候変動に対する適応策
    北海道大学:若手研究者異分野連携型萌芽研究支援(Fusion-H)
    研究期間 : 2015年09月 -2016年03月 
    代表者 : 加藤 知道
  • 太陽光誘発クロロフィル蛍光の画像解析による森林光合成量評価
    アサヒグループ学術振興財団:地球環境科学部門
    研究期間 : 2015年04月 -2016年03月 
    代表者 : 加藤 知道
  • 動的全球植生モデルとデータ同化による気候変化と陸域生態系応答の解明
    日本学術振興会:海外特別研究員(生物学・基礎生物学・「生態・環境」)
    研究期間 : 2008年10月 -2010年09月 
    代表者 : 加藤 知道
  • 温暖化が大気-陸域間の生物地球化学的相互作用に与える影響に関するモデル解析
    日本学術振興会:科研費(基盤B)
    研究期間 : 2007年04月 -2010年03月 
    代表者 : 伊藤昭彦
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2007年 -2010年 
    代表者 : 伊藤 昭彦, 安立 美奈子, 稲冨 素子, 加藤 知道
     
    大気-陸域生態系間で行われる微量ガス交換を介した生物地球化学的相互作用総合的に扱えるよう、陸域生態系モデルVISITの高度化を進展させ、地球環境変動に関する研究に応用した。陸域起源の温室効果ガスのフラックスの空間分布とその時間的変動要因に関するモデル解析を行った。植物からの揮発性有機物質発生、メタン放出・酸化、バイオマス燃焼といった微量ガスフラックスを多数取り込んだモデルを構築し、陸域炭素収支の統合的な評価を行った。フラックス観測が実施されているいくつかのサイトで観測データと比較した検証を行った。
  • 雲量とエアロゾルが陸域炭素循環および大気CO2の安定同位体組成に与える影響
    日本学術振興会:科研費(基盤B)
    研究期間 : 2006年04月 -2009年03月 
    代表者 : デニス・ダイ
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2007年04月 -2009年 
    代表者 : 和田 英太郎, 鈴木 力英, 石井 励一郎, 笹岡 晃征, DENNLS Dye, 小林 秀樹, 加藤 知道, 稲冨 素子, 小林 秀樹, 加藤 知道
     
    グローバルスケールのVISITモデルの結果と人口データを用いて、単位人口あたり利用可能な一次生産量を1995年から2015年の期間について5年間隔で計算しマップ化を行った。次に、国別に集計・解析し、東アジアにおける人間活動が物質循環に与える影響の評価を行った。この研究は野外観測、安定同位体精密測定法、衛星画像処理、陸域生態系モデルの高度化を協働することによって得られた。
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2007年04月 -2008年09月 
    代表者 : 加藤 知道
     
    東アジアの炭素循環を陸域生態系モデルによってより現実に近く再現するため、パラメータ調整の際に観測データを取り込むデータ同化手法を利用し、実際に1979-2003年の陸域炭素循環を推定した。得られた炭素フラックスは、妥当な分布を示し、さらに、CO_2上昇による施肥効果を考慮した場合、しなかった場合よりも、誤差が小さく、データ同化によって、東アジア地域で、モデルの推定精度が向上する可能性が示唆された。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2006年 -2008年 
    代表者 : DYE Dennis, 小林 秀樹, 加藤 知道, 伊藤 昭彦
     
    アジア各地で直達・散乱成分別の光合成有効放射の長期観測を実施し,雲やエアロゾルの変動が光合成有効放射の直達・散乱成分比に与える影響を詳細に解析すると共に,散乱成分が大きい条件下で,光合成量が増加するメカニズムを三次元放射伝達モデル+光合成モデルによる解析で詳細に明らかにした。

教育活動情報

主要な担当授業

  • 食資源環境論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 国際食資源学院
    キーワード : 農業,畜産,生態系,汚染,気候変動,物質循環,微生物,環境管理,健康
  • 食資源学総論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 国際食資源学院
    キーワード : 食資源問題の諸相,生産,環境,ガバナンス,文化,科学技術
  • 食資源環境特論演習
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 国際食資源学院
    キーワード : Please see the English version.
  • 食資源環境特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 国際食資源学院
    キーワード : Please see the English version.
  • 食資源特別演習
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 国際食資源学院
    キーワード : 気象学,気候学,生態学,土壌学,水文学,森林科学
  • 測量学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 農学部
    キーワード : 平面測量,写真測量,地形図,地理空間情報
  • 環境計測学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 農学部
    キーワード : キーワード:リモートセンシング,分光反射特性,地理空間情報,モニタリング,自然環境,農地生態系
  • 環境と人間
    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 : 土壌、水、大気、自然エネルギー、地域、物質循環、Information and communication technology (ICT) と農業生産、作物生産技術、持続的食料生産、農産物の収穫後技術と品質

大学運営

委員歴

  • 2022年01月 - 現在   Ecological Research誌   Handling Editor
  • 2021年04月 - 現在   日本学術会議環境学委員会・地球惑星科学委員会合同FE・WCRP合同分科会iLEAPS小委員会(第25期)   委員
  • 2018年 - 現在   Asiaflux   Steering Committee Member
  • 2014年05月 - 現在   Geoscientific Model Development誌 (欧州地球科学連合)   Topical Editor
  • 2014年05月 - 現在   JapanFlux   Steering Committee Member
  • 2020年04月 - 2021年03月   日本地球惑星科学連合   学協会委員(日本農業気象学会担当)
  • 2018年04月 - 2020年03月   日本農業気象学会   若手研究者の会
  • 2016年04月 - 2019年03月   日本生態学会   ポスター部会
  • 2010年04月 - 2012年03月   日本生態学会関東地区会   会計・編集幹事


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