西太平洋暖池的跃变及其气候效应

THE CLIMATIC JUMP OF THE WESTERN PACIFIC WARM POOL AND ITS CLIMATIC EFFECTS

用 SST (COADS,NCEP) 资料研究热带西太平洋暖池的年代际变化和跃变特征,讨论其气候效应。结果表明:西太平洋暖池有显著的10～20年周期的年代际变化和40～50年周期的气候跃变;一百多年来西太平洋暖池发生了4次大的跃变,在1910年代中期和1950年代中期,西太平洋暖池由异常发展转为异常减弱,1930年代初和1980年代初,西太平洋暖池由异常减弱转为异常发展;西太平洋暖池在1980年代初的跃变,具明显的气候效应,跃变后热带中东太平洋海温显著升高,大范围海域升温超过0.5 ℃,夏季西太平洋副高加强西伸,脊线偏南,我国汛期降水呈南方偏多、北方偏少的分布趋势,与跃变前基本相反。研究结果还表明:在西太平洋暖池异常发展期,El Nino事件出现多且强于La Nina事件,而在西太平洋暖池异常减弱期,La Nina事件出现多且强于El Nino事件。

The climatic jump of the Western Pacific Warm Pool and its climatic effects were analyzed using the SST (COADS,NCEP) data sets. The results show that there were very obvious decadal variability with 10～20 periods and obvious 4 times of climatic jump of the Western Pacific Warm Pool with 40～50 year periods during one hundred years,which happened in 1910s,1930s,1950s and 1980s. The Warm pool jump has important climatic effects and after jump of the Western Pacific Warm pool,the SST increases about 0.5 ℃ in Central and Eastern Tropical Pacific; the Pacific Subtropical High at 500 hPa strengthen and gose southwestward,the precipitation belt tends to be in south China. The results also show that El Nino events will happen more than La Nina events when the Warm pool abnormally develops,and La Nina events will happen more than El Nina events when the Warm pool abnormally declines. Due to the 40～50 year period,the Warm pool is still in its strengthening stage and it is possible that the drought in north China will continue in the first decadal of 21 century.