摘要
低涡是造成浙江区域性暴雨(以下简称低涡暴雨)的重要天气系统,为了解浙江低涡暴雨的大气环流分型及不同环流型的高相关集合动力因子,基于2016—2023年浙江及周边地区格点日降水量和NCEP-FNL再分析资料,利用多变量经验正交分解法(Multi-Variable Empirical Orthogonal Functions,MVEOF)及模拟退火算法和多元随机化技术相结合的客观分型法(Simulated ANnealing and Diversified RAndomization,SANDRA)对2016—2023年浙江44个低涡暴雨日的环流场进行分型,并优选不同环流型的主要集合动力因子。结果表明,MVEOF和SANDRA两种分型方法都将浙江低涡暴雨分为暖区型、锋面型和回流型,以暖区型发生频次最多,锋面型次之,回流型最少。各环流型低涡多在浙江中西部造成降水,以整层一致西南风暖区型低涡暴雨强度及落区最大。不同环流型造成浙江暴雨的外部条件不同:暖区型低涡暴雨,中尺度类的集合动力因子是优选因子;锋面型低涡暴雨,其优选因子既包含中尺度类因子,大尺度水汽和垂直运动与暴雨发生也有较大关联;回流型低涡暴雨,中尺度类因子相关性减弱,优选因子为大尺度散度及其相关因子。
The vortexes are important weather systems that cause regional rainstorms in Zhejiang.To investigate the atmospheric circulation patterns and their associated dominant ensemble dynamic factors,we classify the circulations of 44 vortexes that induced rainstorm in Zhejiang and surrounding areas based on grided daily precipitation data,as well as the NCEP-FNL reanalysis data from 2016 to 2023.The classification is achieved using the Multi-Variable Empirical Orthogonal Functions(MVEOF)combined with an objective typing method that integrates Simulated Annealing and Diversified Randomization(SANDRA).Additionally,we diagnose the preferred ensemble dynamic factors contributing to the rainstorms under different circulation patterns.Results show that both classification methods categorize rainstorm-induced vortexes into three types:warm sector type,frontal type,and return flow type,with warm sector type occurring most frequently,followed by the frontal type,and the return flow type being the least common.Under various circulation patterns,vortexes typically induce precipitation in central and western Zhejiang.The warm-sector type,characterized by consistent southwesterly winds,produces the strongest rainstorm and widest coverage.The diagnosis and selection of ensemble dynamic factors under different circulation patterns reveal that external conditions causing rainstorms in Zhejiang vary among types.For the warm sector type,mesoscale dynamic factors are the preferred factors;in the frontal type,in addition to mesoscale factors,large-scale water vapor and vertical motion induced by the vortexes also play a role;in the return flow type,the influence of mesoscale factors diminishes,while the role of large-scale divergence-related factors increases significantly.
作者
郑艳
蔡志颖
张程明
肖王星
吴俊杰
水旭琼
顾思南
ZHENG Yan;CAI Zhiying;ZHANG Chengming;XIAO Wangxing;WU Junjie;SHUI Xuqiong;Gu Sinan(Ningbo Zhenhai Meteorological Bureau of Zhejiang Province,Ningbo 315200;Ningbo Meteorological Observatory of Zhejiang Province,Ningbo 315000;Ningbo Jiangbei Meteorological Bureau of Zhejiang Province,Ningbo 315000;Ningbo Ecological Environment Meteorological Center of Zhejiang Province,Ningbo 315000;Zhejiang Institute of Meteorological Sciences,Hangzhou 310008)
出处
《暴雨灾害》
2025年第5期700-712,共13页
Torrential Rain and Disasters
基金
浙江省自然科学联合基金项目(LZJMZ23D050004)
浙江省宁波市公益性科技计划项目(2023S061)
浙江省宁波市重点研发计划暨“揭榜挂帅”项目(2023Z139)
浙江省宁波市气象局一般项目(NBQX2023001B)。
关键词
低涡暴雨
MVEOF
SANDRA
集合动力因子
rainstorm induced by vortexes
MVEOF decompose
SANDRA clustering
dynamic factors
