【摘要】 基于滦河流域1960—2017年逐日降水数据,运用Mann-Kendall非参数检验法、Pettitt法、经验正交分解(EOF)等方法,分析了滦河流域降水集中度(PCD)和降水集中期(PCP)的时空变化特征.结果表明:近60a来,滦河流域PCD平均值为0.71,呈显著的下降趋势.PCP平均值为203.3,年内降水多集中在7月22—23日左右,呈现出微弱的下降趋势.PCD在1996年前后发生突变,而PCP的突变特征不明显.近60a来,PCD和PCP变化趋势的空间分布存在明显区域差异.乐亭、唐山、青龙和承德地区PCD的降幅较大且达到了显著性水平,PCP在中游的青龙地区下降幅度较大.EOF分析结果表明:滦河流域PCD和PCP以全区一致型的空间分布为主,流域上游与中下游反向的分布格局次之.滦河流域年降水量与PCP相关性较差,而与PCD具有较好的相关性,其中青龙、乐亭、秦皇岛和唐山等中下游地区都表现出显著正相关,说明滦河流域中下游地区年降水越集中,年降水量和日最大降水量也相应越大,使得当地发生洪涝灾害的概率增大.位于流域上游的多伦和围场地区PCD、PCP与年降水量相关性都不显著,这对于当地的水土保持是相对有利的.更多还原

【Abstract】 Mann-Kendall test,Pettitts test and Empirical Orthogonal Function(EOF)were applied to daily precipitation data from sixteen meteorological stations within or adjacent to the study area spatialtemporal variations in precipitation concentration degree(PCD)and precipitation concentration period(PCP)in Luanhe River Basin from 1960-2017 were analyzed.In the most recent 60 a,the mean PCD was found to be0.71,with an apparent decreasing trend,with a rather uniform distribution of intra-annual precipitation.The mean PCP was found to be 203.3,showing an insignificant declined trend,with annual precipitation concentrated from 22 to 23 July.An abrupt change in PCD occurred around 1996,but the precise point for this abrupt change in PCP was not detected.The change trends of PCD and PCP exhibited marked spatial variations.Larger change magnitude in PCD with significant negative trends occurred in Leting,Tangshan,Qinglong and Chengde in the middle reaches,but Qinglong showed a large change in PCP.PCD and PCP were mainly congruous in the whole region;in the upper and middle-lower reaches a reverse distribution pattern was also seen.Annual precipitation was poorly correlated with PCP,but was well correlated with PCD.The positive relationship between PCD and annual precipitation passed the significant level of 0.01 This means that the higher PCD,the greater annual precipitation and maximum daily precipitation,therefore increasing the probability of local flooding.Correlations between PCD,PCP and annual precipitation in Duolun and Weichang in the middle reaches were not significant,this being relatively favorable for local soil and water conservation.更多还原