Analysis of abnormal climate characteristics of the"20·6"persistent rainstorm process in Guangxi
Based on the daily precipitation data of 91 surface meteorological stations in Guangxi and the reanalysis data of the NECP/NCAR geopotential height field,the abnormal characteristics of the"20·6"continuous rainstorm process in Guangxi were analyzed.The results showed that:(1)there were good divergence conditions at high levels,which were conducive to the occurrence and maintenance of heavy precipitation in northeastern Guangxi.The circulation situation of"two troughs and one ridge",the deepening of the trough on the eastern side and the eastward movement of the split trough were also conducive to the occurrence and maintenance of heavy precipitation in northeastern Guangxi.(2)The onset of the South China Sea summer monsoon was early,and the South China Sea summer monsoon was active,leading to the establishment of water vapor channels from the Indian Ocean and the South China Sea.(3)The subtropical high was located northward and its western ridge point was located westward.The easterly airflow from the south side of the subtropical high converged with the warm and humid southwesterly airflow in the Bay of Bengal,which was conducive to the occurrence and maintenance of heavy precipitation.(4)In the early stage of this process,the convection suppression band of tropical atmos pheric low-frequency oscillation moved eastward obviously and maintained stably in the western Pacific.The convection band of tropical atmospheric low-frequency oscillation was active in the Indian Ocean,which brought abundant water vapor to the rainstorm in Guangxi.The above conditions were conducive to the development and maintenance of persistent rainstorm process in Guangxi.
国家科技期刊平台
NSTL
万方数据
