鄱阳湖流域降水集中指标的时空变化特征

Temporal and spatial change characteristics of precipitationconcentration index in Poyang Lake Basin

研究降水在年内的集中程度,对干旱、洪涝及水资源管理具有重要意义。本文基于1957—2012年鄱阳湖流域的月降水资料,并利用两种降水集中度(PCI和PCD)指标、一种降水集中期(PCP)指标,研究了降水集中指标在鄱阳湖流域的适用性及其时空变化特征。结果表明采用的这些降水集中指标在鄱阳湖流域有较好的适用性。两种降水集中度指标均呈现出由西南向东北逐渐增加的趋势,其时空分布特征十分相似。降水集中期变化范围为4月上旬至6月中旬,呈由西向东逐渐减少的趋势。通过对月降水集中几种指标的变化进行MMK趋势检验,发现流域内大部分站点的降水集中度指标呈不显著的减小趋势,降水集中期呈不显著的延后趋势。

The study on monthly distribution of annual precipitation is of great significance to drought or flood and water resources management.Based on the monthly precipitation data of 14 meteorological stations in Poyang Lake Basin from 1957 to 2012,the Precipitation Concentration Index(PCI),Precipitation Concentration Degree(PCD)and Precipitation Concentration Period(PCP)were applied to analyze the monthly distribution of annual precipitation.Moreover,the modified Mann-Kendall(MMK)trend test method was used to detect the trend of precipitation concentration indices.The results show that these indices are applicable in Poyang Lake Basin.The spatial and temporal variability of precipitation concentration detected by the PCI and PCD is very similar.The precipitation concentration index gradually increased from southwest to northeast in the Poyang Lake Basin.The variation range of precipitation concentration period is from early April to mid-June,with a decreasing trend from west to east.The precipitation concentration index shows an insignificant decrease trend in most stations in the Poyang Lake Basin.Additionally,the PCP result shows an insignificant delay trend.