中文摘要：

利用NCEP／NCAR再分析资料及NOAA的OLR资料，研究了春季南亚高压在中南半岛上空建立与500hPa副高在孟加拉湾上空断裂的关系。结果表明，南亚高压建立之前，对流从“海洋大陆”向北推进，首先在中南半岛建立；而孟加拉湾地区由于青藏高原感热作用在对流层中低层形成一个反Hadley环流型的局地经圈环流，15°N附近500—700hPa有下沉运动中心，它抑制了孟加拉湾对流的建立，也不利于500hPa副高带断裂。南亚高压在中南半岛建立之后，位于高压中心西南侧的孟加拉湾上空出现一个强的辐散中心，孟加拉湾地区15°N附近的下沉运动消失，对流发展起来，降水量增加并释放大量潜热，非绝热加热中心位于500hPa，此时副高脊线断裂。因此，高层南亚高压建立所产生的辐散运动很可能对孟加拉湾上空500hPa副高带断裂及对流建立起到了触发作用。

英文摘要：

Based on the NCEP/NCAR reanalysis and NOAA OLR data, this paper studies the relation- ship between the establishment of South Asian high （SAH） over the Indo-China Peninsula （ICP） and the splitting of 500 hPa subtropical high over the Bay of Bengal （ BOB ） in springtime. Results show that,before the establishment of SAH, the convective activity extends northward from the ＂Maritime Continent＂ and establishes initially over the ICP. In concert with this, a local anti-Hadley cell displays in the mid-lower tropospheres over BOB due to the sensible heating induced by the Tibet Plateau. This local meridional cell results in a descending center near the 15°N of BOB from 500 hPa to 700 hPa, which suppresses the development of convective activity and thus becomes unfavorable for the splitting of 500 hPa subtropical high in this region. After the establishment of SAH over ICP, a strong divergence centre shows in the upper troposphere over BOB, accompanied by disappearance of the mid-low tropo- spheres descending center near the 15°N of BOB. Consistent with this, convective activity develops over BOB and coincides with increasing of precipitation and releasing of latent heating. This induces a diabatic maximum center at 500 hPa and thus intercepts the ridge of subtropical high over BOB. There- fore, the divergence effect induced by the upper SAH establishment possibly triggers the establishment of convective activity and the splitting of 500 hPa subtropical high over BOB.