摘要
利用正压涡度方程模式对赤道东太平洋和赤道西太平洋暖池区海温异常影响华北夏季降水的机制进行了研究,结果表明:(1)赤道东太平洋海温升高,西太平洋副高会前期加强,位置异常偏北,后期位置偏东;华东25°N以南多低槽活动,华北上空低槽活动少;华北东部盛行南风,长江中下游盛行北风扰动,不利于水汽向华北输送。这些形势都不利于华北降水。(2)西太平洋暖池区海温降低,副高减弱,不利于华北降水;华北上空多低槽活动,是有利于降水的形势;渤海、朝鲜半岛盛行北风,而贝加尔湖及其东南方向为强南风,冷暖空气不易交汇,华北降水稀少。(3)西太平洋暖池海温降低对华北降水的影响不象赤道东太平洋海温异常那样显著。(4)极涡变化和热带海温异常之间的对应关系不确定。
By using a global spectral model of quasi - geostrophic barotropic vorticity equation including diabatic heating, the probable mechanism for SSTA impact on summer rainfall in north China was investigated in this paper. Results show when SSTA in the tropical eastern Pacific is positive, the situation of sub - tropical high is far north from the normal, then far east, the rainfall in north China is less; when SSTA in the western Pacific warm pool is negative,the sub -tropical high weakened, summer rainfall is less also in north China; but the impact of abnormal SST in western Pacific warm pool on summer rainfall in north China is not so notable as SSTA in the tropical Pacific; and the relative relation between Polar vortex change and SSTA in the tropical Pacific is not fixed.
出处
《干旱气象》
2006年第2期5-11,共7页
Journal of Arid Meteorology
基金
河北省气象局气象科学基金资助
关键词
海温异常
华北降水
物理机制
SSTA
summer rainfall in north China
physical mechanism
