赣江流域不同等级降水变化特征及其与大尺度气候相关性研究

Variation Characteristics of Rainfall at Different Levels and Its Correlation with Large-scale Climate Indices on Gangjiang Basin

为阐明赣江流域近60 a不同等级降水变化特征及其可能影响因子,基于赣江流域11个气象站点1960~2017年的逐日降水数据,采用一元线性趋势、滑动t检验、小波分析和反距离加权空间插值等方法分析了赣江流域各等级降水量、降水日数及降水强度的时空变化特征,并探讨了其与北极涛动等21个大尺度气候指数的相关性。结果表明:(1)1960~2017年期间,赣江流域小雨、中雨的降水量和降水日数呈现减少趋势,2000年减少趋势最为显著;而大雨、暴雨的降水量和降水日数表现为增加趋势,1990年增加趋势最为显著;各等级降水强度均呈现增加态势;各指标均存在26和19年的2个明显的变化周期;(2)赣江流域大雨和暴雨的降水量、降水强度及降水日数表现为由东北向西南递减趋势,小雨量和小雨日数呈现西高东低的分布特征;总降水强度和小雨日数分别在整个流域呈显著增强和减少趋势,大雨量和大雨日数在流域东北部呈显著增加趋势;(3)东大西洋遥相关型、西太平洋副热带高压面积、强度和西伸脊线位置对流域当年大雨和暴雨影响显著;北大西洋涛动对次年中雨和大雨影响显著。

Based on the daily precipitation data of 11 meteorological stations in Ganjiang River Basin(GRB)from 1960 to 2017,the variation characteristics of rainfall amount,intensity,and days at all levels in the basin was analyzed by using linear trend method,slidingT-test,wavelet analysis and Inverse Distance Weight(IDW),and then the correlation between rainfall indicators and large-scale climate indices such as Arctic Oscillation was explored.The results showed that:(1) During 1960-2017,the rain amounts and rain days of light rain and moderate rain present a decreased trend and the trend was significant in 2000;while the rain amounts and rainy days of heavy rain and storm rain had an increasing trend and the trend was significant in 1990.For the rainfall intensity,the change of each grade showed an increasing trend.Furthermore,rainfall amount,days and intensity at different grades had two obvious quasi-periods of 26 and 19 years.(2) The rainfall amount,intensity,and days of heavy rain and rainstorm in GRB showed a decreasing trend from northeast to southwest,while the distribution characteristics of rainfall amount and days of light rainfall were higher in the west and lower in the east.For the spatial variation trend,the total rainfall intensity increased significantly in the whole basin,while the days of light rain showed a significant decrease trend in the whole basin.The amount and the days of heavy rainfall increased significantly in the northeast of the basin.(3) Among the 21 large-scale climate indexes,Eest Atlantic,Western Pacific Subtropic High Area,Western Pacific Subtropic High Intensity,Western Pacific Subtropic High Western Ridge Point mainly significant affected heavy rain and rainstorm in the current year,while North Atlantic Oscillation had the most significant impact on moderate rain and heavy rain in the next year.