摘要:选取我国东南沿海热带气旋登陆数目多、经济发达的浙江和福建两省，利用国家级地面气象站逐小时降水观测资料，结合热带气旋降水客观分离方法，对1956~2012年（共57年）浙、闽两省沿海登陆热带气旋降水开展客观分离，统计分析热带气旋登陆期间降水精细化时空分布特征。结果表明：热带气旋平均路径在登陆前6小时至登陆后24小时呈西北行，累积降水具有明显非对称分布特征，与主要水汽辐合区相吻合，登陆后24小时至48小时的降水分布与鄱阳湖水体以及局地地形有密切联系；伴随登陆进程，降水分布呈现显著变化，登陆前，浙、闽两省降水较强；登陆后，降水范围向内陆扩展到浙、闽两省以外地区；登陆点聚类分析指出，所有类别的较强降水时段均位于登陆前12小时至登陆后6小时，但不同类别的降水分布和演变特征具有显著差异，这种差异与局地地形和热带气旋环流所处位置关系密切；小时强降水统计分析显示，伴随着登陆进程强降水频次分布逐渐变化和向内陆地区推进，高频次强降水主要出现在登陆前、后6小时的浙、闽两省沿海地区，且以两省交界附近地区最为集中，与该地区明显的高大地形分布有着密切的关系。两省各台站由登陆热带气旋带来的小时降水极值差异较大，从10到143 mm均有分布，大部分极值在30至60 mm之间。其中，极值大于50 mm的站点主要分布在沿海地区，在浙、闽交界处较为集中，与小时强降水的频次分布一致。
关键词:热带气旋/
降水分布特征/
浙、闽两省/
精细化观测/
统计分析
Abstract:Temporal and spatial distribution characteristics of tropical cyclone (TC) precipitation are investigated in the present study over Zhejiang and Fujian Provinces, where TCs frequently make landfall, using hourly precipitation observations collected at national ground surface weather stations and the objective synoptic analysis technique of TC.The results show that the averaged track of TCs from 6 hours pre-landing to 24 hours after landing appears to move northwestward and the accumulated precipitation is characterized by an asymmetric distribution, which is consistent with the water vapor convergence area.The rainbelt is parallel to the coastline and the rainfall distribution from 24 hours to 48 hours after the TC landing is closely related to effects of Poyang Lake and local topography.The distribution of precipitation changes significantly with the inland moving of TCs.Heavy rainfall is concentrated in Zhejiang and Fujian Provinces and expands to inland areas that are even beyond the two provinces after landing.The cluster analysis of TC landfall locations indicates that all types of TC precipitation are the heaviest from 12 hours pre-landing to 6 hours after landing.However, rainfall distribution and evolution characteristics of different types of precipitation vary notably due to the influence of local topography and the location of TC circulation.Statistical analysis of hourly heavy rainfall reveals that high frequency of heavy rainfall appears in the coastal areas of Zhejiang and Fujian Provinces from 6 hours pre-landing to 6 hours after landing, and concentrates along the border of the two provinces due to the precipitous terrain in this region.Hourly precipitation extremes caused by landing TCs in the two provinces vary from 10 mm to 143 mm, while most are between 30 mm and 60 mm.Stations with hourly precipitation of more than 50 mm are mainly located over coastal areas and along the border of Zhejiang and Fujian Provinces.The distribution of extreme hourly precipitation is consistent with that of hourly heavy rainfall frequency.
Key words:Tropical cyclone/
Distribution characteristics of precipitation/
Zhejiang and Fujian Provinces/
Accurate observations/
Statistical analysis
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