1971~2018年四川省极端降水指数时空变化特征

Spatial and Temporal Variation of Extreme Precipitation Indices in Sichuan Province from 1971 to 2018

摘要: 为了研究四川省极端降水指数的时空变化、突变特征和影响因素，利用1971~2018年四川省35个气象站点的逐日降水资料，采用线性倾向估计法、Mann-Kendall检验法、滑动t检验和反距离加权插值(IDW插值)方法研究，得出如下结论：1) 1971~2018年四川极端降水指数时间序列变化不显著，只有降水强度SDII呈显著上升趋势。2) 年总降水量PRCPTOT、大雨日数R20、暴雨日数R50、5日最大降水量RX5day和降水强度SDII的突变集中发生在20世纪80~90年代，暴雨日数R50和强降水量R95p在2009年也发生突变，特强降水量R99p突变年份集中在2004年。3) 川西高原、川西南地区持续无雨日和极端降水量增加；盆地中部和南部持续干期增加和年降水量减少使得此区域趋于干旱化，盆地东部发生洪涝灾害风险较大。4) 经度和海拔高度影响因素对极端降水指标影响较大，随着经度自西向东增加，海拔自西向东降低，极端降水指数具有增加的趋势。5) 除持续干期CDD和1日最大降水量RX1day，其余指数和年总降水量有较大相关性，其中对年降水量影响较大的指数为强降水量R95p、中雨日数R10和大雨日数R20。

Abstract: Daily precipitation data sets of 35 meteorological stations in Sichuan Province from 1971 to 2018 were used to calculate extreme precipitation indexes. Linear trend estimation method, Mann-Kendall test, moving t-Test Technique and inverse distance weight interpolation method were used to study the spatial-temporal change characteristics, mutation characteristics and influencing factors of extreme precipitation indexes in Sichuan Province. The conclusions are as follows: 1) From 1971 to 2018, there was no significant change in the time series of extreme precipitation indexes in Sichuan Province, and only the SDII index has shown a significant upward trend. 2) The mutations of PRCPTOT, R20, R50, RX5day and SDII occurred in the 1980s to the 1990s, and the mutations of R50 and R95p also occurred in 2009, and the mutations of R99p were concentrated in 2004. 3) According to the spatial variation characteristics, the continuous rainless days and the increase of extreme precipitation in the western Sichuan plateau and the southwestern Sichuan are prone to extreme precipitation events. The increasing of continued dry period and the decreasing of annual precipitation make the Central and Southern Sichuan Basin tend to be arid, the risk of flood disasters in the eastern part of the basin is relatively high. 4) From the perspective of influencing factors, longitude and altitude have a greater impact on the extreme precipitation indexes than latitude. With the increase of longitude from west to east and the decrease of altitude from west to east, the extreme precipitation indexes have an increasing trend. 5) Most indexes (except CDD and RX1day) are highly correlated with annual precipitation, among which the indexes that have a great influence on annual precipitation are R95p, R10 and R20.