近50年贵州不同强度降水日数时空变化分析

Spatial and temporal variations of rainfall days with different intensities in Guizhou in recent 50 years

利用1961年-2010年贵州省81个气象站的逐日降水量资料,采用线性倾向估计、Mann-Kendall检验和GIS空间分析,探讨了贵州省不同强度降水日数的时空演变规律和突变特征,结果表明:近50年,不同强度降水日数呈先增加后减小的态势,总降水日数表现为明显下降趋势,下降速率为1.93d/(10a),其中小雨日数对总降水日数变化趋势的贡献最大,两者均在2006年发生突变,转为急剧下降趋势。在空间分布上,总降水日数和小雨日数总体分布态势由西南向东北递减,黔西南的大方、纳雍、水城等地为高值区,黔东南以及东北局部地区为低值区;中雨日数和大雨以上日数则由东南向西北递减。不同地区降水日数以减少为主,其中总降水日数和小雨日数在黔南地区减少比较明显,中雨日数呈减少趋势的比例高达90.1%,而大雨以上日数为增加趋势的比例较大(44.5%),呈条带状分布,主要在黔西、黔东北以及黔中南等地。

Based on the daily precipitation data at 81 meteorological stations in Guizhou Province from 1961 to 2010,the spatial and temporal variations and abrupt change of rainfall days with different intensities were analyzed using the methods of linear trend analysis,Mann-Kendall test,and GIS spatial analysis.The results showed that the rainfall days with different intensities increase gradually from the 1960 sto 1990sand decrease in the early 2000 s,the total rainfall days present an obvious decreasing trend with a rate of 1.93d/10 a,and the light rainfall days account for most of total rainfall days as both have an abrupt decreasing trend in 2006.As for the spatial distribution,the total rainfall and light rainfall days decrease from southwest to northeast with higher-value centers in Dafang,Nayong,and Shuicheng in the southwest and lower-value areas in the southeast and northeast of Guizhou Province,while the medium rainfall and heavy rainfall days decrease from southeast to northwest.The rainfall days decrease in different area of Guizhou Province.The total rainfall and light rainfall days have a significantly decreasing trend in the south of Guizhou Province,the proportion of moderate rainfall days shows a decreasing trend of 90.1%,and the area of heavy rainfall days with an increasing trend accounts for 67.1% and is mainly located in the west,northeast,and south central Guizhou Province with a banding distribution.