气候变化对大盈江流域径流的影响

Impacts of climate change on runoff in the Daying River Basin

为揭示大盈江流域气候变化对径流的影响,基于SWAT模型,通过设置不同情景,定量分析了气候要素对流域内径流的影响,并结合RCP4.5、RCP8.5这2种气候情景对流域未来径流的变化进行了预估.结果显示:1)SWAT模型在大盈江流域径流模拟中具有较好的适用性,可以用SWAT模型进行流域的径流模拟,率定期模型参数R2、CEns分别为0.68、0.66,验证期R2、CEns分别为0.69、0.67;2)流域内径流的变化趋势与降雨量变化趋势成正比,与气温变化趋势成反比,1995-2015年间,大盈江流域内降雨的减少和气温的升高导致月均径流量下降3.58m^3·s^-1;3)在RCP4.5和RCP8.5这2种气候情景下,2021-2050年大盈江流域径流均呈减少趋势,减少的速率分别为15.43亿和6.48亿m^3·(10a)^-1,这与1976-2015年间,流域实测径流减速为1.87亿m^3·(10a)^-1的变化趋势一致,但这2种情景下,径流的减少趋势明显增强,分别达到1976-2015年减速的8.26、3.47倍.

With SWAT model and quantitatively analyses,impact of climatic factors on watershed runoff in different scenarios was examined to reveal the influence of climate change on variations in watershed runoff.Combined with RCP4.5 and RCP8.5 climate scenarios,future changes in runoff in the Daying River Watershed were predicted.SWAT model was found to perform well in simulating Daying River Basin runoffs and can be used to vsimulate runoff in Daying River Basin.Parameters R 1 and EiivS were determined to be 0.68 and 0.66 in parameter calibration periodic respectively,and 0.69 and 0.67 in the period of validation respectively.The trend of runoff in the basin was proportional to the trend of rainfall and inversely proportional to the trend of temperature.The decrease in rainfall and increase in temperature in the Daying River Basin resulted in a decrease in monthly average runoff of 3.58 m 1#s 1 from 1995-2015.Under the RCP4.5 and RCP8.5 climatic scenarios,the runoff in the Daying River Basin showed a decreasing trend from 2021-2050,with decreasing rates of 15.43×10^8 m^3•(10a)^-1 and 6.48×10^8 m^3•(10 a)^-1 respectively.These data are consistent with the trend of deceleration of measured runoff of 1.87×10^8 mJ•(10 a)^-1 in the Daying River Basin from 1976-2015.Under these two scenarios,the trend of runoff reduction increased significantly,reaching 8.26 and 3.47 times respectively for the 1976-2015 deceleration.