岷沱江流域径流对气候和土地利用变化的响应

Response of runoff to climate and land use change in Minjiang and Tuojiang River Basin

为探究岷沱江流域径流对气候和土地利用变化的响应,构建了岷沱江流域SWAT分布式水文模型,并采用情景分析方法从时空尺度上定量分析了1981-2014年间岷沱江流域气候和土地利用变化对径流量的影响。结果表明:SWAT模型在岷沱江流域适用性较好,可用模型模拟流域径流;气候和土地利用变化均引起流域径流量减少,且气候变化的影响强度显著大于土地利用变化的影响强度,气候和土地利用变化分别对流域内大渡河和沱江径流量影响最大;仅考虑气候变化,流域径流量与降雨变化呈正相关关系,与气温变化呈负相关关系,气候变化对流域内大渡河径流量影响最大;仅考虑土地利用变化,将流域坡度25°以上耕地转化为林地和坡度15°~25°之间的耕地转化为草地,均会引起流域径流量的微弱减少,分别对流域内大渡河和岷江径流量影响最大,而将全部林地转化为草地则会导致流域径流量的微弱增加,大渡河径流量增加最大。

In order to explore the response of runoff to land use and climate change in Minjiang&Tuojiang River Basin,a hydrological SWAT(soil and water assessment tool)model of Minjiang&Tuojiang River Basin was constructed to quantitatively evaluate the effects of land use and climate change on the runoff in Minjiang&Tuojiang River Basin from 1981 to 2014 on spatio-temporal scale using scenario analysis.The results show that the SWAT model is applicable to the runoff simulation of Minjiang&Tuojiang River Basin.Both climate and land use change will induce a decrease in runoff in this basin,and the influence intensity of climate change is significantly greater than that of land use change.They have the greatest influence on the runoff of Dadu River and Tuojiang River respectively.Only considering climate change,the runoff is positively correlated with the percipitation change,but negatively correlated with the temperature change in this basin.In addition,climate change has the greatest impact on the runoff of Dadu River.When only considering the land use change,both the conversion of cultivated land of25°slope and above into forest land and cultivated land of 15°-25°slope into grassland will cause a slight reduction of runoff in this basin,and the former has the greatest impact on the runoff of Dadu River,the latter on Minjiang River,respectively.The conversion of all forest land into grassland will lead to a slight increase in the runoff with the largest increase in Dadu River.