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本文分析华南夏季风降水(P_(SM))与热带气旋降水(P_(TC))在年际和年代际尺度上的物理联系,结果表明:在年际变化上,华南P_(SM)与P_(TC)呈显著负相关。南海-西北太平洋的气旋性涡度和相对湿度增加以及垂直风切变减弱,有利于更多的热带气旋生成,从而使得华南P_(TC)增加。同时异常增暖的赤道中太平洋SST和异常偏冷的北印度洋SST会激发南海-西太平洋异常气旋,加之中国东部-日本异常反气旋的作用,使得华南P_(SM)减少。在年代际尺度上,华南P_(SM)与P_(TC)呈显著正相关,在1990s初华南P_(SM)与P_(TC)明显增加。其中,南海生成的热带气旋对华南P_(TC)年代际增多有重要贡献。前期冬春季西太平洋持续异常偏暖的SST会通过垂直环流的作用引起热带印度洋SST增暖并持续到夏季,之后偏暖的热带印度洋SST又反馈作用于西北太平洋异常反气旋,使得华南P_(SM)增加。1990s初南海夏季风爆发年代际偏早,促使华南上空的大气显热源从5月持续增加至夏季,从而有助于东亚副热带夏季风的增强和华南P_(SM)增加。
This paper analyzes the interannual and decadal physical relationships between summer monsoon rainfall (P SM) and tropical cyclone precipitation (P TC) in South China. The results show that P_ (SM) and P_ (TC) showed a significant negative correlation. The increase of cyclonic vorticity and relative humidity and the decrease of vertical wind shear in the South China Sea - Northwest Pacific are more favorable for the formation of tropical cyclones, resulting in an increase of P_ (TC) in South China. At the same time, the anomalous warming of the equatorial Pacific SST and the abnormally cold North Indian SST will stimulate the South China Sea - West Pacific anomalous cyclone, coupled with the anomalous anticyclone in eastern China - Japan, making South China P_ (SM) decreased. On interdecadal scale, there was a significant positive correlation between P_ (SM) and P_ (TC) in South China, and the P_ (SM) and P_ (TC) increased significantly in South China at the beginning of 1990s. Among them, the tropical cyclone generated in the South China Sea has an important contribution to the decadal increase of P_ (TC) in South China. In the early winter and spring, the persistent anomalously warm SST in the western Pacific will induce the SST warming in the tropical Indian Ocean through the vertical circulation and continue to the summer. After that, the warmer tropical Indian SST feedbacks to the anomalous anticyclone in the Northwest Pacific, making the P_ (SM) )increase. The early onset of the South China Sea summer monsoon onset in the early 1990s led to a significant increase of the atmospheric salient heat source over the South China Sea from May to summer, contributing to the enhancement of the East Asian subtropical summer monsoon and the increase of P SM in South China.