辽宁省近50年旱涝灾害的时空特征分析

基于1960—2009年辽宁省49站的逐日降水资料,从单站旱涝Z指数出发,根据Z指数的划分等级定义了辽宁省的区域旱涝指标,以此讨论了辽宁省年度旱涝灾害和季节性旱涝灾害的时间变化趋势和空间分布特征。结果表明:50a来,年度干旱、夏旱、秋旱指标呈上升趋势,春旱指标的时间变化趋势特征不明显,年度洪涝和夏涝指标呈下降趋势;从空间分布来看无论是年度干旱还是季节性干旱,发生频率最高的地区都在辽宁省西部及西北部地区;辽宁东北地区的年度干旱、春旱、夏旱出现频率较低,秋旱出现频率最低的地区在辽宁省南部。年度洪涝和夏季洪涝的空间分布特征比较相似,发生频率最高的地区在辽宁省东部及东南部地区,西部地区发生洪涝的频率是最低的。旱涝灾害的严重程度与降水集中度的大小具有一定的相关性

Spatiotemporal Distribution of Drought and Flood Disasters over the Last 50 Years of Liaoning Province

Based on the daily precipitation data from 1960 to 2009 of 49 stations in Liaoning Province,temporal trend and spatial distribution of annual and seasonal drought and flood disasters were discussed according to the drought and flood region index which is defined by the grade division of Z-index of single station.The results show that annual drought,summer drought and autumn drought index have increasing trend,and temporal trend of spring drought index is not obvious over the last 50 years.There are both decreasing trend of annual and summer flood index.The spatial distribution of either annual drought or seasonal drought shows that the highest frequency regions are in the west and northwest Liaoning Province.Annual drought,spring drought and summer drought have lower frequency in northeast Liaoning Province,and the lowest frequency regions of autumn drought are in the east and the southeast.The spatial distribution of annual flood and summer flood disaster is similar,the highest frequency regions are in the east and the southeast,and the lowest is in the west of Liaoning Province.There is some correlation between severity of drought and flood disasters and the concentration degree of precipitation.