1980-2015年贵州省不同等级降雨日数时空变化特征

Spatio-temporal characteristics of precipitation days of different levels in Guizhou Province from 1980 to 2015

使用贵州省19个气象站1980-2015年的36年逐日降水观测数据,通过计算气候态、倾向率、雨日概率、线性系数,运用样条函数插值法、Mann-Kendall突变检验等现代统计诊断方法,研究了贵州省不同地貌各等级降雨日数的时空分布特征和不同等级降雨日数的趋势变化。得到以下结论:1980-2015年,贵州省各地降雨日数多年平均值在130~200 d之间,全省年总雨日平均值为171 d,小雨日数占总雨日数的81.31%,对降雨日数的贡献最高,总雨日时空分布由小雨型决定,空间分布上,总体表现为西多东少,中部多南北少;暴雨和大雨日数在空间上呈带状分布,南多北少;中雨日数出现两个大值中心,一个位于东部,另一个位于西南部的岩溶盆地;暴雨和大雨日整体呈微弱上升趋势,而中雨、小雨、总雨日数呈下降趋势,总雨日下降趋势最显著;岩溶峡谷的雨日数最多,非喀斯特区和岩溶槽谷的雨日数最少。暴雨、大雨、中雨日数高值区在岩溶盆地,低值区在岩溶峡谷;降雨日数冬半年少于夏半年,冬季是全年中降雨日数最少的季节,以南部地区较少;贵州省总雨日年内分布可分为3类:平缓型、单峰型、双峰型,岩溶槽谷、非喀斯特区和岩溶高原地区属于平缓型;峰丛洼地地区为单峰型;岩溶峡谷和岩溶盆地为双峰型;小雨日、总雨日数在1997-1998年发生突变,呈显著的下降趋势,暴雨、大雨、中雨日数没有发生突变。

Based on the daily observed rainfall dataset of 19 stations in Guizhou Province during 1980-2015,the spatio-temporal distribution features and the trend variation features of different precipitation day levels in different geomorphological types were investigated with methods of spline function interpolation and Mann-Kendall abrupt change test,combined with the calculation of climatic states,tendency rates,rainy day probability and linear coefficients.Results show that the average annual precipitation days of Guizhou Province was 171 days,which ranged from 130 to 200 days in different parts of this province.Light precipitation days made up 81.31%of the total precipitation days,so it determined the spatio-temporal distribution of the total precipitation days.The distribution of precipitation days showed remarkable regional characteristics,which increased from east to west and from north and south to central part.The spatial distribution of rainstorm and heavy precipitation days was in a strip pattern,which decreased from south to north.The moderate precipitation days had two centers of high values,which were located in the east and a karst basin of the southwest.It is also evident that the number of rainstorm and heavy precipitation days showed a slight upward trend,whereas the moderate precipitation days,light precipitation days and total number of precipitation days all showed the opposite,with the total precipitation days decreasing most significantly.The number of precipitation days was the highest in the karst gorge,but lowest in the non-karst and karst troughs.The maximum values of rainstorm,moderate and heavy precipitation days were in the karst basin,and the minimum values in the karst gorge.The number of precipitation days from March to August was greater than that from September to February,with the least number of precipitation days appearing in the winter,even less in the south.The annual distribution of total precipitation days were categorized into 3 types,which were gently,unimodal and bimodal type.Karst trough,non-karst and karst plateaus were all classified as gently type,peak clusters was unimodal type,karst gorge and karst basin were bimodal type.The numbers of light precipitation days and total precipitation days changed abruptly to a decreasing trend during 1997 to 1998,whereas the numbers of rainstorm,heavy and moderate precipitation days remained their courses.