近52年大伙房水库流域径流系数变化趋势和特征

基于1961—2012年降水量和径流量数据,分析了大伙房水库流域近52a径流系数的年代际、年际以及季节变化趋势和特征。结果表明:(1)径流系数的年代际变化趋势平缓;(2)月平均径流系数在年内呈波动变化,每年6—7月偏低,12月—次年1月,3—4月,8月偏高;(3)年径流系数呈不明显的增高趋势,最小值出现在1988—1992年,最大值出现在2008—2012年。1980年以前,径流系数呈现下降趋势,1980—2000年径流系数呈现周期波动变化,2000年以后径流系数呈现上升趋势,1965年、1968年、1971年、2010年和2011年年径流系数均发生了突变。

Variation trends and characteristics of runoff coefficient of Dahuofang Reservoir Basin in recent 52 years

Based on the data of precipitation and runoff from 1961 to 2012，the decadal，annual and seasonal variation trends and characteristics of runoff coefficient of Dahuofang Reservoir Basin in recent 52 years are analyzed herein. The result shows that（1）the decadal variation trend is gentle；（2）the monthly average runoff coefficient presents a fluctuated variation within a year，i.e. slightly lower during June-July，and slightly higher in the periods of December-next January，March-April and August；（3）the annual runoff coefficient presents an unobvious increasing trend，i.e. the minimum values occur during 1988-1992，while the maximum values appear during 2008-2012. The runoff coefficient shows a decreasing trend before 1980 and presents a cyclic fluctuated variation during 1980-2000，and then gives an increasing trend after 2000，moreover，all the annual runoff coefficients of 1965，1968，1971，2010 and 2012 are abruptly changed.