| Project/Area Number |
09839028
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
自然史科学
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| Research Institution | TOKYO METROPOLITAN UNIVERSITY |
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Principal Investigator |
NOGAMI Michio Tokyo Metropolitan University, Professor, 大学院・理学研究科, 教授 (50087144)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAMOTO Takashi Tokyo Metropolitan University, Assistant Professor, 大学院・理学研究科, 助手 (60285096)
MATSUYAMA Hiroshi Tokyo Metropolitan University, Assistant Professor, 大学院・理学研究科, 助手 (50264586)
MASUDA Koiiti Tokyo Metropolitan University, Associate Professor, 大学院・理学研究科, 助教授 (30181647)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | vegetation index / phenology / temperature / precipitation / evapotranspiration / water budget / climate / フェノロジー / 水収支式 / 気候値 / 有効降水量 |
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| Research Abstract |
This report deals with the seasonal change of global vegetation detected by remotely sensed image data and pursues the cause in relation to climate. The data used in this study are NDVI(normalized vegetatin index) files for 1986-1988 in 10 minute spatial resolution, and monthly Temperature and Precipitation data set in 30 minute spatial resolution prepared by NGDC, USA. Climatic data were interpolated to 10 minute resolution by considering the topographic effect, that is, lapse rates and DEMs. And all were interpolated to semimonthly data under constraint to keep the same yearly average or total value. Water supply, actual evapotranspiration, water storage change and resultant runnoff for each pixsel were calculated at semimonthly intervals by a newly developed model of water balance and snow accumulation-melting. The assumptions used in this model are, we believe, in the range of natural phenomena and there remains a way to improve assumptive values in the model through comparing calculated basin runoff and observed river discharge. Maps of semimonthly actual evapotranspiration and VI values were showed as animated images by a newly developed system in this project. Not only time-serial but also spatial change of vegetation and climatic parameters were quickly percepted in the animated maps and then spatial correlation of the two were analyzed statistically. We found that vegetational greenness change (fresh green and defoliation) happens simultaneously or with semimonthly delay to crossing a threshold value of actual evapotranspiration. We conclude that greenness of global vegetation is under control of the unique climatic parameter, actual evapotranspiration, neither two independent parameters temperature and precipitation nor a simple combination of the two.
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