热带海温异常影响夏季环流的机制研究

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夏季大气环流的机制进行了研究,结果表明:太平洋海温异常会对大气环流产生明显的影响,我国上空环流受其直接影响较小,大气对赤道东太平洋海温升高的响应比对西太平洋暖池海温降低响应明显.西太平洋暖池海温降低和赤道东太平洋海温升高都使极涡明显减弱,对中低纬度大气高度场的影响相反.赤道东太平洋海温升高,中低纬度地区槽脊活动表现不明显,而西太平洋暖池海温降低,会使大气高度场产生明显的槽脊扰动.西太平洋暖池海温降低和赤道东太平洋海温升高,会使涡度场、经向风形成沿驻波波列传播的扰动场.西太平洋暖池海温降低和赤道东太平洋海温升高同时发生时,经向风场使北半球所有的地方都产生了扰动(两条波列路径仍然清楚),沿纬圈和经向都呈有规律的正负相间的分布,扰动表现为驻波特征.

Mechanism for the Impact of Tropical SSTA on General Circulation in Summer

In this paper, using a global spectral model of quasi-geostrophic barotropic vorticity equation including diabatic heating, we studied the probable mechanism for SSTA to affect summer atmosphere circulation. Results show that the SSTAs in the tropical Pacific have notable influence on summer circulation, and the response to the SSTA in eastern equatorial Pacific is more visible than that to the SSTA in western Pacific warm-pool. The negative SSTA in western Pacific warm-pool can effect waves rising and falling on circulation, however, the positive SSTA in eastern equatorial Pacific can not. Either positive SSTA in western Pacific warm-pool or negative SSTA in eastern equatorial Pacific can create an teleconnection in vorticity field and meridional wind field. As negative SSTA in western Pacific warm-pool and positive SSTA in eastern equatorial Pacific occur at the same time, the variation of meridional wind field are very complicated, responses spread all over the Northern Hemisphere, and perturbantions show a character of stationary waves.