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- Title
1979--2019 年云贵高原夏季区域性极端日降水事件的 异常环流特征.
- Authors
夏阳; 陈金梅; 李明刚; 字冉; 吴华洪; 肖艳林
- Abstract
Based on daily precipitation observations and NCEP / NCAR reanalysis data, the circulation anomalies of regional daily precipitation extremes (RDPEs) at or above the 99th percentile over Yunnan-Guizhou Plateau during boreal summers of 1979--2019 are investigated by using composite analysis. Our results suggest that there were 35 RDPEs in recent 41 years which mostly occurred in early July and the least in mid-August and the threshold for RDPEs was 20.0 mm / d. Among the 35 RDPEs, four were affected by tropical cyclone systems, and their precipitation centers were mainly in southwestern Guangxi and the southern coastal areas of Guangxi with more than 75 mm precipitation at the center. The precipitation centers of the other 31 RDPEs were mainly in central and southern Guizhou and northern Guangxi, and the intensity of the precipitation center was significantly weaker than that of the RDPEs affected by tropical cyclone systems. Due to zonal wave train disturbance in the mid-latitude area (30~ 50 ° N) of Eurasia and abnormal vertical circulation in the low-latitude area, a deep abnormal upward movement occurred in the troposphere of the Yunnan-Guizhou Plateau, which, together with the abnormal anticyclonic circulation at 500 hPa, led to the water vapor transport from the South China Sea and Bay of Bengal to the Yunnan-Guizhou Plateau, providing favorable dynamic conditions and water vapor conditions for the formation of precipitation extremes over the Yunnan-Guizhou Plateau. At the same time, the gradient of heating field caused by abnormal cooling in the surrounding areas strengthened the inflow of air flow, further facilitating the formation and maintenance of precipitation extremes. Moreover, the RDPEs were also related to the activities of low value systems from the Ural Mountains to northeastern China and the propagation of wave disturbance energy from the North Atlantic and low-latitude areas in the tropics.
- Publication
Journal of Tropical Meteorology (1004-4965), 2023, Vol 39, Issue 4, p603
- ISSN
1004-4965
- Publication type
Article
- DOI
10.16032/j.issn.1004-4965.2023.052