西北太平洋冷海温对东亚初夏大气环流影响的数值研究  

Numerical Study on the Effects of Persistent Cold Sea Surface Temperature on the Northwest Pacific Ocean in Atmosphere Circulation During the Early Summer in East Asia

作　　者：袁佳双[1] 郑庆林[2] 

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]中国气象科学研究院,北京100081

出　　处：《应用气象学报》2006年第3期310-315,共6页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(40576012和40531006);干旱气象科学研究基金项目(IAM200512);国家海洋局极地科学重点实验室项目(KP2005008)共同资助

摘　　要：利用改进的NCARCCM3气候模式，研究了1992年西北太平洋持续冷海温对东亚初夏季节大气环流的影响。西北太平洋冷海温不利于初夏东亚南支西风急流季节性北移，引起亚洲东部沿海低槽明显加深，东亚大槽平均高度场降低了4．66dagpm，从而也不利于西太平洋副热带高压的西伸加强。西北太平洋冷海温还不利于我国大陆初夏温度场回升，特别是引起我国东北地区近地面温度下降2～5℃，是影响东北冷夏现象的重要原因之一。模拟结果表明，1992年初夏江淮入梅期较常年偏晚，降水异常偏少，与紧邻东亚大陆的西北太平洋持续冷海温有关。Ocean as a large heat resource, its persistent sea surface temperature anomaly （SSTA） during the winter half year stirs upper air heating anomaly over it, contributing to atmospheric circulation variation in East Asia region in early summer. By employing the improved NCAR/CCM3 climate model, and designing two experiments which use different sea surface temperature anomaly （SSTA） over northwest Pacific ocean （6.66°-51.11° N, from East Asia western coast to about meridian）, using real monthly SSTA in Exp-A and climate mean SSTA in Exp-B, study is undertaken of the effects of cold SSTA on circulation transformation in the early summer in East Asia in 1992. This model considers well the influence of Tibetan Plateau topography, and the surface roughness length is improved in the context of new TIPEX data, thereby improvs the long term prediction and simulation ability over East Asia region. The investigations indicate that persistent cold SSTA from winter to early summer in 1992 over northwest Pacific ocean is significantly unfavorable for south branch westerly jet＇s northward seasonal shifting and Tibetan Plateau temperature gradient backspin from winter to summer, exhibiting the temper- ature decrease of 0--1 ℃ in the north side and increase of 1--2 ℃ in the south side of Tibetan Plateau at early summer, maintaining a west wind center of maximum speed of 5 m/s, 2 m/s on 200 hPa and 500 hPa respectively, resulting in the south branch westerly jet＇s persistence and enhancement. The cold SSTA in the north- west Pacific ocean reduces the heat release into the atmosphere, inducing the low trough＇s obuious deepening and the average geopotential height in east Asia dropping by 4.66 dagpm, therefore the cold air in the rear of the cold front invades the lower latitude area so the south branch of the front is southing, and is unfavorable for the west Pacific subtropical high＇s westwards move and strengthening. It also makes surface mean temperature at early summer decrease by 1--2℃ in central Chin

关 键 词：西北太平洋 持续冷海温 季节转换 数值试验 

分 类 号：P434[天文地球—大气科学及气象学]