| Mechanism of the Spring Persistent Rains over southeastern China |
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| 作者单位： | WAN RiJin（State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Mechanicals (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;Guangdong Climate and Agrometeorology Center, Guangzhou 510080, China;Shanghai Typhoon Institute of China Meterological Administration, Shanghai 200030, China） ;WU GuoXiong（State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Mechanicals (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China） ; |
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| 基金项目： | 中国科学院资助项目;国家自然科学基金;国家重点基础研究发展计划(973计划) |
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| 摘 要： | The Spring Persistent Rains (SPR) in the areas to the south of middle and lower reaches of the Yangtze River or over southeastern China (SEC) is a unique synoptic and climatic phenomenon in East Asia. This study reveals a possible mechanism responsible for the climatic cause of SPR formation through climatic mean data analysis and sensitive numerical model experiments. SEC is located at the down-stream of the southwesterly velocity center (SWVC) which lies on the southeastern flank of the Tibetan Plateau (TP). As a result, there are strong southwesterly wind velocity convergence and moisture con-vergence over SEC. This is the immediate climatic cause of SPR formation. In spring, the seasonal evolution of the southwesterly velocity consists with the surface sensible heating over southeastern TP, indicating that the formation of SPR is related to not only the southwesterly wind of mechanical de-flected flow of TP, but also the southwesterly wind of thermal-forced cyclonic low circulation. Sensitive numerical experiments demonstrate that, without TP, both SWVC and the SPR rain belt will disappear. The southwesterly wind velocity increases almost linearly with the amount of the total diabatic heating with TP rising. Therefore, SWVC is the result of the mechanical forcing and thermal forcing of TP. All these strongly suggest that the presence of TP plays a primary role in the climatic formation of SPR.
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| 收稿时间： | 2006-01-24 |
| 修稿时间： | 2006-05-29 |
Mechanism of the Spring Persistent Rains over southeastern China |
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| Wan RiJin,Wu GuoXiong. Mechanism of the Spring Persistent Rains over southeastern China[J]. Science in China(Earth Sciences), 2007, 50(1): 130-144. DOI: 10.1007/s11430-007-2069-2 |
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| Authors: | Wan RiJin Wu GuoXiong |
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| Affiliation: | 1. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Mechanicals (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;Guangdong Climate and Agrometeorology Center, Guangzhou 510080, China;Shanghai Typhoon Institute of China Meterological Administration, Shanghai 200030, China
2. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Mechanicals (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China |
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| Abstract: | The Spring Persistent Rains (SPR) in the areas to the south of middle and lower reaches of the Yangtze River or over southeastern China (SEC) is a unique synoptic and climatic phenomenon in East Asia. This study reveals a possible mechanism responsible for the climatic cause of SPR formation through climatic mean data analysis and sensitive numerical model experiments. SEC is located at the down-stream of the southwesterly velocity center (SWVC) which lies on the southeastern flank of the Tibetan Plateau (TP). As a result, there are strong southwesterly wind velocity convergence and moisture con-vergence over SEC. This is the immediate climatic cause of SPR formation. In spring, the seasonal evolution of the southwesterly velocity consists with the surface sensible heating over southeastern TP, indicating that the formation of SPR is related to not only the southwesterly wind of mechanical de-flected flow of TP, but also the southwesterly wind of thermal-forced cyclonic low circulation. Sensitive numerical experiments demonstrate that, without TP, both SWVC and the SPR rain belt will disappear. The southwesterly wind velocity increases almost linearly with the amount of the total diabatic heating with TP rising. Therefore, SWVC is the result of the mechanical forcing and thermal forcing of TP. All these strongly suggest that the presence of TP plays a primary role in the climatic formation of SPR. |
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| Keywords: | SPR climatic cause of formation southwesterly Tibetan Plateau sensitive experiments |
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