【摘要】 使用日本气象厅提供的 1980～ 1997年TBB资料、NCEP/NCAR 4 0a再分析资料及CMAP降水资料 ,分析了亚澳“大陆桥”地区降水和对流活动特征及其影响因子 ,发现苏门答腊地区降水和对流具有明显的季节变化。 4月底～ 5月初(2 5候 )雨区沿“大陆桥”和中南半岛西海岸迅速北移 ,对流也有类似特征 ,正是对流移动的突然加速 ,对随后中南半岛对流增强有直接影响。进一步研究表明 ,苏门答腊地区对流的强 (弱 )与海温异常及纬圈环流的变化相联系 ,由于正好位于两个热力直接环流 (Walker和反Walker)耦合区的苏门答腊地区对流增强 ,使得垂直环流的上升支增强 ,导致整个环流强度发生变化 ,引起赤道西风增强 ,进而影响中南半岛对流爆发。更多还原

【Abstract】 Based on 1980-1997 TBB data from GMS of Japan, NCEP/NCAR reanalysis data (1958-1997) and 1980-1997 precipitation data from CMAP, an investigation is carried out of seasonal changes of precipitation and convection over Asian-Australian ”land bridge” areas and its relationship with SST. The results show that the precipitation and convection over Sumatra take on clearly seasonal changes with abundant (less) rainfall in winter (summer). The rainband over Sumatra moves northwestward rapidly along ”land bridge” in late-April and early-May (the 25 thpentad) and the convection shows similar variations. It is the accelerating of the convection that affects directly the subsequent enhancement of the convection over Indo-China Peninsula area. The further study suggests that the intensity of Sumatra convection has a close relation to the SSTA and Zonal vertical circulations: the strengthening of the convection over ”land bridge” which lies just at the coupling point of two thermal direct circulation (Walker and anti-Walker circulation) leads to a corresponding enhancing of updraft of vertical circulations, or even a corresponding enhancing of the whole zonal circulation followed by the strengthening of the equatorial westerly, which might influence the onset of the Indo-China Peninsula convection.更多还原