气象研究与应用2025，Vol.46Issue(1)：1-8,8.DOI:10.19849/j.cnki.CN45-1356/P.2025.1.01
华南前汛期暴雨多寡的热动力差异分析
Analysis of the thermodynamical differences in the rainstorm anomalies during the pre-flood season in South China
摘要
Abstract
Based on the daily rainfall data of 65 representative stations in South China from 1961 to 2021 and the ERA-Interim reanalysis data of the European Centre for Medium-Range Weather Forecasts,the differences of environmental conditions such as water vapor,instability and dynamic forcing between the years with anomalous more rainstorm events and those with anomalous less rainstorm events in the pre-flood season in South China were diagnosed by using the synthetic analysis method,an index of conditional moist potential vorticity flux(CMF index)containing the corresponding factor combinations was calculated,aiming to quantitatively reveal the intrinsic connection between the index and the rainstorm anomalies.Results showed that the average number of rainstorm days in the pre-season in South China during the 61-year period from 1961 to 2021 exhibited significant inter-annual variations,with values fluctuating from 0.8 to 6.3 d.The interannual variation of rainstorm was large,with a one-fold difference between the maximum number of rainstorm days(66 d)and the minimum number of rainstorm days(33 d);and the difference in the number of storm stations was even more significant,with the maximum number of stations(287)being 3.7 times that of the minimum number of stations(77).Further comparative analysis revealed that in the years with more rainstorm events,there was a positive value of the 200 hPa divergence field in South China,indicating strong upper-level divergence,and a westward extension of the 500 hPa subtropical high to 120°E,which was favorable for the transportation of southwesterly flow to South China.Meanwhile,an anomalous cyclonic circulation and the vorticity positive anomaly was formed in the northern part of South China at 850 hPa,thus showing a convergence zone at the lower level.The water vapor flux field in the whole layer showed anomalous cyclonic convergence.On the contrary,there was a negative anomaly at the 200 hPa divergence field,a retreat of the 500 hPa subtropical high to 135°E,and an anticyclonic circulation of the 850 hPa wind anomaly field and an anticyclonic radial divergence of the whole-layer water vapour flux anomaly field in the northern part of South China.In particular,the constructed CMF index of the wet level vortex showed a positive correlation with the amount of rainstorms,which was a finding that not only deepens the understanding of the thermodynamic mechanism of rainstorms during the pre-flood season in South China,but also has application value in the diagnosis of rainstorm forecasting.关键词
华南前汛期/暴雨异常/热动力条件/湿位涡/垂直通量指数Key words
the pre-flood season in South China/rainstorm anomalies/thermodynamical conditions/moist potential vorticity/vertical flux index分类
大气科学引用本文复制引用
陈剑飞,刘会鹏,黄明策,韦美闹,赖珍权,朱丽云..华南前汛期暴雨多寡的热动力差异分析[J].气象研究与应用,2025,46(1):1-8,8.基金项目
广西重点研发计划项目(桂科AB22080101)、广西自然科学基金项目(2022GXNSFAA035482、2023GXNSFBA026342) （桂科AB22080101）
