热带西太平洋对流活动与中国夏季降水

RELATIONSHIP BETWEEN CONVECTIVE ACTIVITY OVER TROPICAL PACIFIC AND RAINFALL OVER CHINA IN SUMMER

利用 1 979～ 2 0 0 3年月平均射出长波辐射 (OLR)资料 ,分析了中国夏季江淮多 (少 )雨年的同期及前期热带太平洋地区OLR场分布特征。通过定义和计算OLR对流强度指数 ,探讨对流活动与中国夏季雨型的关系。结果表明 ,夏季热带西太平洋地区平均对流活动强度与同期江淮地区降水有很好的反相关关系 ,即当热带西太平洋地区对流活动强时 ,江淮地区降水易偏少 ,当对流活动弱时 ,江淮地区降水易偏多。不仅如此 ,前期冬、春季对流活动强度与夏季对流活动强度有明显的正相关关系 ,则可利用前期冬、春季对流活动强度对当年中国夏季降水趋势进行预测和补充订正。因此 ,热带西太平洋地区对流活动强弱对于中国夏季降水预测有一定的指示意义。

Mean monthly OLR distributions over tropical Pacific during 1979-2003 were analyzed in relation to the rainfall over China in summer. The characteristics and relationship between convective activities and the Huaihe Valley precipitation were studied by calculating OLR convective intensity indexes. The main results were obtained as follows:(1) There is positive correlation between the OLR value over tropical west Pacific and the Huaihe Valley precipitation indexes in summer.(2) There is negative correlation between the convective activity intensity index and the Huaihe Valley precipitation indexes in summer. There was same correlation in winter and spring.