1980—2017年南海季风爆发前后华南前汛期降水统计特征对比分析  

Statistical characteristics of pre-summer rainfall over South China before and after South China Sea monsoon onset from1980 to 2017

作　　者：李争辉 罗亚丽[1,2] LI Zhenghui;LUO Yali(State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044)

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044

出　　处：《暴雨灾害》2021年第2期101-110,共10页Torrential Rain and Disasters

基　　金：国家重点研发计划(2018YFC1507400)。

摘　　要：利用1980—2017年华南地区303个国家级地面气象站逐小时降水数据、ERA-Interim再分析资料,分析华南前汛期(4—6月)降水统计特征,定义站点上短时(1—6 h)、中等时长(7—12 h)和长时(>12 h)降水事件,对比降水量、频次和强度在南海季风爆发前后的变化,以及所定义的西部内陆、东部内陆、沿海地区的异同。结果表明:(1)南海季风爆发后,研究区域平均而言,三类降水事件的降水量增多、小时降水强度增强,短时、长时降水事件发生频次增多,而中等时长降水事件发生频次有所减少。(2)从空间分布来看,南海季风爆发后,小时降水强度在整个华南地区均增强,西部内陆时长大于6 h的降水事件尤为明显;降水事件的发生频次在西部内陆和沿海地区升高,而东部内陆时长大于6 h的降水事件发生频次降低,因此,季风爆发后西部内陆和沿海地区的总降水量均显著增大,而东部内陆的总降水量变化不大。(3)西部内陆降水事件主要在夜间开始发生,持续时间越长的事件越早开始,且由西向东逐渐推迟;东部内陆短时降水事件主要在14时(北京时,下同)左右开始,季风爆发后更为明显,而时长大于6 h的降水事件的开始时间和峰值时间无明显的分布规律;沿海地区短时降水事件在季风爆发前主要于05—08时开始,季风爆发后,在海岸线约50 km以内仍然如此,而较远离海岸线的短时降水事件主要于14时开始,沿海地区长时降水事件在季风爆发前、后都倾向于在夜间开始,并在日间出现峰值。Climatological characteristics of pre-summer(April-to-June)rainfall over South China(SC)are examined using 1980-2017 hourly rainfall observations at the national-level weather stations and the ERA-Interim reanalysis data.The short-(1-6 h),moderate-(7-12 h),and long-duration(>12 h)rainfall events are defined at individual stations.The rainfall amount,occurrence frequency,and intensity of the three rainfall types are compared between the two periods of the pre-summer rainy season,i.e.,pre-and post-monsoon-onset periods,as well as among three designated subregions,namely,the west inland,east inland,and coastal regions.The major findings are as follows.(1)After the onset of South China Sea(SCS)monsoon,the average rainfall amount and hourly rainfall intensity increase over the entire SC irrespective of the rainfall-events’duration.The occurrence frequency increases for both the short-(1-6 h)and long-duration(>12 h)rainfall types,but decreases for the moderate-duration(7-12 h)rainfall type.(2)The rainfall amount,frequency and intensity show pronounced regional variations and substantial sub-seasonal variations over SC.Owing to more favorable thermodynamic conditions after the monsoon onset,rainfall intensifies over entire SC,with larger increases of the longer-duration(>6 h)events over the west-inland region.Moreover,the rainfall events occur more frequently over the west-inland and coastal regions,but less over the east-inland region.As a result,the total rainfall amounts increase over the west-inland and coastal regions after the onset of monsoon,while changing little over the east-inland region.(3)The rainfall events over the west-inland region mainly occur in nocturnal hours during both periods,with the longer-duration events beginning earlier and the beginning and peaking hours of each rainfall type delaying gradually from west to east.The short-duration rainfall events dominantly initiate in the afternoon(about 14:00 BT)over the east-inland,which is more prominent after the SCS monsoon onset,while the beginning

关 键 词：华南前汛期降水 南海季风爆发 降水事件 降水时长 降水日变化 

分 类 号：P467[天文地球—大气科学及气象学]