Researcher Database
Last Updated :2024/07/25
Researcher Profile and Settings
Master
Affiliation (Master)
- Research Faculty of Agriculture Fundamental AgriScience Research Bioresource and Environmental Engineering
Affiliation (Master)
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Profile and Settings
Degree
Profile and Settings
Name (Japanese)
OkadaName (Kana)
KeijiName
200901073227115209
Achievement
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Research Areas
MISC
- Keiji Okada, Takashl Machimura, Ikuo Horiguchi, Shinichi Urano Journal of Agricultural Meteorology 56- (4) 261 -273 2000/09/01 [Not refereed][Not invited]
A new method for estimation of regional evapotranspiration using satellite derived datais proposed. This method estimates daily regional evapotranspiration by combining high resolution LANDSAT-TM data, NOAA-AVHRR data of which the estimation accuracy of surface temperature is high, and wide-area representative radiosonde data. As a case study, we caluculated the epavotranspiration for 2 districts in the Hokkaido Ishikari Plain using this method. Results are reasonable. Though there is no direct method for verification, comparison with the Prisetley-Taylor method shows that the results correctly reflect the effects of land use. This result shows that this method is sensitive to land use and that it is a useful method for estimation of the regional evapotranspiration. The representativeness of the radiosonde data is questionable in the comparison between results from 2 regions. Though there are some details to be improved, this could be a valuable method by which the regional evapotranspiration can be estimated using easily obtainable data. © 2000, The Society of Agricultural Meteorology of Japan. All rights reserved. - OKADA Keiji, URANO Shinichi, MACHIMURA Takashi, HORIGUCHI Ikuo Journal of agricultural meteorology 56- (4) 261 -273 2000 [Not refereed][Not invited]
- Seasonal Variations in the Turbulence Spectra Above and Within a Decidons ForestJ. Agric. Meteorol 52- (5) 509 -512 1997 [Not refereed][Not invited]
- Machimura T., Nakai T., Okada K., Tanaka Y., Urano S., Horiguchi I. J. Agric. Meteorol 52- (5) 497 -500 1997 [Not refereed][Not invited]
The decoupling theory presented by Jarvis and McNaughton (1986) was used in the comparison of the evapotranspiration characteristics of forest, corn and alfalfa canopies. The average values of the decoupling factor Ωc were 0.53, 0.74 and 0.88 in the forest, corn and alfalfa, respectively, which was in the opposite order for the aerodynamic roughness of the canopies. Ωc varied largely with the change of the canopy resistance. The Ωc indicated the variability of the ratio of the evapotranspiration to the available energy (lE/A). When Ωc<0.8, the reliability of the evapotranspiration models based on the available energy (e. g. Priestley-Taylor model) should decrease. - decopling式による群落蒸発散の評価北海道の農業気象 (48) 21 -26 1996 [Not refereed][Not invited]
- Characteristics of Canopy Evapotranspiration Using 'decoupling' Equation(48) 21 -26 1996 [Not refereed][Not invited]