浙江省侵蚀性降雨集中特性研究

Concentration Characteristics of Erosive Rainfall in Zhejiang Provence

基于浙江省84个气象台站1980-2009年逐日降水资料,运用Mann-Kendall趋势检验法和空间径向基函数插值法对侵蚀性降雨集中特性指标进行了时空特征分析.结果表明：浙江省平均侵蚀性年降雨量为1129.3 mm,月尺度分配呈双峰型,历年侵蚀性降雨集中度平均为0.407,平均集中期为第179.5 d（6月29日）,集中时段平均长80.6d,主要分布在6-8月内;侵蚀性降雨集中特征指标年际、年代际变化特征明显,并在20世纪初发生了突变.在空间分布上侵蚀性年降雨量由北向南递增;集中度由东北向西南递增,沿海地区递增梯度大,中部地区递增梯度小;但集中期则呈现为由东北向西南递减;降雨集中时段表现为浙江中部集中时段较长,沿海地区集中时段较短;集中开始时间和结束时间均由东北向西南递减,并呈现大梯度变化区域带.

Based on the daily precipitation data from 1980~2009 of 84 meteorological stations in Zhejiang Province, the spatial and temporal distributions of concentration characteristics of erosive rainfall were analyzed by the methods of nan-parametric Mann-Kendall test and radial basis function interpolation. The results indicated that the annual mean erosive rainfall was 1129.3mm with the bimodal distribution at monthly scale. In the study region, the mean concentration degree of erosive rainfall in the past 30-year was 0.407 and the mean concentration period was 179.5d. Meanwhile, the mean length of concentration duration was 80.6d mainly distributed in June to August. On the time scales, the interannual and interdecadal variations of the concentration characteristics were obvious with abrupt changes in the early 20th century. On the spatial distribution, an increasing tendency in erosive rainfall was showed from the northern to the southern in Zhejiang province. And also, the same tendency in concentration degree was showed from the northeast to the southwest with increasing greatly in coastal area and increasing slowly in central region of Zhejiang province. However, the concentration period appeared as in contrast to the concentration degree. Moreover, longer concentration duration occurred in central region and shorter concentration duration in coastal area. Besides, the starting and ending date of concentration duration both showed a decreasing tendency from northeast to the southwest with a large gradient belt region.