1979年7、8月东亚地区赤道缓冲带的结构及其活动

本文利用美国华盛顿气象中心发布的1979年7、8月逐日格点风资料(范围35°S—35°N、85°—145°E),分析了东亚赤道缓冲带结构及其活动特征。结果表明东亚赤道缓冲带为对流层中低层不对称暖性系统,其内为负涡度、辐散下沉区;并发现7、8月它的活动是不相同的,7月缓冲带活动在1°N—1°S赤道附近,8月稳定在2°N以北地区。文中指出7、8月赤道缓冲带活动不相同是由于在这个期间西太平洋副热带高压第二次季节性北跳,经向大尺度环流产生一次明显的调整造成的。

THE STRUCTURE AND ACTIVITY OF EQUATORIAL BUFFER ZONE OVER EAST ASIA DURING JULY-AUGUST 1979

In this paper , by using the daily grid point wind data ( 5 °× 5 °) in July-August 1979 which were broadcast by NMC (U.S.A) and other routine-data, we analysed the structure and activity of equatorial buffer zone over east Aaia The results show that equatorial buffer zone over eastAsia is a warm asymme-tric weaiher system in middle and lower troposphere. Negative vor-ticity and divergence downdraft can be found within its domain. And it is found that its activity is different in July and August. The buffer zone usually situates near the equatorial area (1°N-1 °S) during July, whereas it swings to the north of 2°N and will be almost stationary over there during August. Some evidence indicated that this difference is caused by the second seasonal northward jumping of the west pacifc subtropical high. In this period, an obvious adjustment of the longitudinal large-scale circulation would take place.