2000--2020 年西太平洋热带气旋路径对江淮梅雨期 降水的影响研究.

Based on the precipitation data of automatic weather stations, CMA-STI and ERA5 data from 2000 to 2020, this paper found that, less than half of the tropical cyclone activities were accompanied by heavy rain that occurred in the Jianghuai region, and only 30% of the tropical cyclones were in the company of daily precipitation in the Jianghuai area reaching the average daily amount in the Meiyu period of that year. Except for a few "path-turning type" tropical cyclones and "northwest-traveling type" tropical cyclones that continued to move eastward or northward after landfall, most of the other tropical cyclones were accompanied by the weakening of Meiyu. The WRF model and the built-in TC bogus method were used to simulate the 2017 typhoon Merbok and the 2019 typhoon Danas to verify the influence mechanism of TC on Meiyu. The results show that the model well simulated the path, precipitation area and intensity of the two typhoons. By comparing the tests before and after the removal of the typhoons, it was found that the "northwest-traveling type" typhoon Merbok strengthened a low-level jet with the westward airflow at the southern edge at the early stage, a Yangtze-Huaihe valley shear strengthened, a low pressure headed northward after landing, and a subtropical high was stable, forming a circulation situation favorable for precipitation. After removing Merbok, the low-level jet broke, the subtropical high retreated southward, the water vapor in the South China Sea could not be transported to the Yangtze-Huaihe valley, and the precipitation in the middle and lower reaches of the Yangtze River decreased. With the northward movement of both the path-turning type typhoon Danas and the the subtropical high, convective instability decreased and vertical ascending motion weakened. A large amount of water vapor from the western Pacific was transported to the vicinity of the typhoon eye. The water vapor transport and precipitation in the Yangtze-Huaihe valley decreased and the Meiyu was interrupted. After removing Danas, the precipitation in the east increased, the subtropical high was stable, and the Meiyu was maintained. [ABSTRACT FROM AUTHOR]