2001 Fiscal Year Final Research Report Summary
Observational study on the vegetation-soil moisture-atmosphere interaction over arid regions
| Project/Area Number |
10680103
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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 |
自然地理学
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
SHINODA Masato Tokyo Metropolitan University, Graduate School of Science, Associate Professor, 理学研究科, 助教授 (30211957)
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| Project Period (FY) |
1998 – 2000
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| Keywords | drought / land-surface / atmosphere interaction / Sahel / arid region / Soil moisture observation / Soil moisture model |
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| Research Abstract |
The present study focused on the observational perspective in exploring the land surface-atmosphere interaction and its impact on the drought occurrence over the Sahelian Niger. One of the major characteristics of the present study lies in the multiyear ground-based observations of vegetation, soil moisture, and atmosphere.
Two simple soil moisture models useful for drought monitoring and climate-change studies - were proposed, based on four-year ground observations of root-zone soil moisture in the Sahelian Niger. One is a water balance model that calculates soil moisture using daily precipitation and temperature ; the other is a statistical model, a modified antecedent precipitation index calculated using only daily precipitation. Both models estimated seasonal and inter-annual variations in the observed soil moisture quantitatively well ; the estimations correlated strongly (0.94) with the observations.
The influence of the interdecadal Sahelian drought and resulting soil moisture deficit on air temperature is explored, using the above-mentioned simple water balance model. Evidence demonstrated a series of processes that interdecadal precipitation anomalies influence the time-lagging temperature through soil moisture. These processes were clearly seen only during the beginning one or two months of the dry season, and then both the concurrent soil moisture and temperature anomalies disappeared. This suggests that the root-zone soil moisture does not act as a memory of rainfall anomaly into the following rainy season and is not related to the long-term persistence of the drought.
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