On the effect of the land-ocean contrast to the monsoon circulation
| Project/Area Number |
02452058
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | Center for Climate System Research, University of Tokyo |
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Principal Investigator |
SUMI Akimasa Center for Climate System Research, University of Tokyo Professor, 気候システム研究センター, 教授 (10179294)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 1991: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Monsoon / Coupled Model / land-ocean contrast / Numerical experiment / atmospheric model / interannual variation / land-ocean thermal contrast / モンス-ン / 海陸分布 / 海陸の熱的コントラスト / 大気ー海洋結合モデル / モンス-ン循環 |
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| Research Abstract |
Characteristics of the coupled land-ocean atmosphere system have been investigated by using numerical models. Numerical experiments have been designed and conducted in two different experimental set-up ; (1) an atmospheric model is used with assumed Sea Surface Temperature (SST), and (2) an ocean-atmosphere coupled model is used.
Two extreme cases were investigated ; (1) the land surface is desert-like, where few evaporation is supplied, and (2) the land surface is swamp, where infinite moisture supply from land surface can be expected. In both cases, rectangular ocean, which extends from 90ﾟE to 270ﾟE between 60ﾟN and 60ﾟS,is assumed.
Following conclusions were obtained ;
(1) When the land surface is dry, thermal contrast between land and sea is strong (land surface temperature is higher than SST), and the heat low are generated over the land. Convection center is located to the east of the ocean, and the monsoon westerly is also located in the eastern part of the ocean. This feature is also confirmed in the couled model run, where SST tends to be zonally uniform.
(2) When the land surface is wet, the thermal contrast between land and ocean is reverse (Tg SST) to the previous case. In this case, convection center and the monsoon westerly is located to the western part of the ocean. This feature is also confirmed in the coupled-model run, where the SST in the eastern part of the ocean tends to decrease due to the upwelling caused by a strong easterly.
In summary, it is suggested that there exists characteristic flow regimes corresponding to the land-ocean heat contrast.
It is also shown where the seasonal forcing is stron, there is no interaseasonal variation.
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Report
(3 results)
Research Products
(3 results)
