基于SWAT模型分析嘉陵江流域蓝、绿水资源量的时空变化特征

嘉陵江流域是成渝双城经济圈发展的重要水源区，其水资源状况的变化对实现我国新发展格局有重要影响。基于SWAT模型对嘉陵江流域水文过程进行模拟，探究了1981-2020年及典型年嘉陵江流域的蓝、绿水时空分布特征，采用Mann-Kendall(M-K)分析年际间蓝、绿水资源量的变化趋势。结果表明：流域多年平均降水量为931 mm，为蓝、绿水资源量之和，蓝水资源量多年均值为386 mm，占降水量的41.5%；绿水资源量多年均值为545 mm，占降水量的58.5%，1981-2020年流域降水量和绿水资源量总体呈增加趋势，蓝水资源量呈减少趋势。特枯水年、平水年、特丰水年的蓝水资源量分别为165.61、456.71和643.70 mm，绿水系数在典型年变化差异较大。空间上，流域内蓝水资源量、绿水资源量与降水量的分布特征相似，呈现从上游到下游先减小后增大、西少东多的空间格局。

Temporal and spatial variation characteristics of blue and green water resources in Jialing River Basin based on SWAT model

The Jialing River Basin is an important water source area for the Chengdu and Chongqing economic circle, and the status change of its water resources has a significant impact on the realization of new development pattern in China. Here, the hydrologic process of Jialingjiang River Basin was simulated based on SWAT (soil and water assessment tool) model to explore the temporal and spatial distribution features of blue and green water in this area in some typical years and during the period of 1981-2020, and then Mann-Kendall (M-K) test was used to analyze the interannual variation trend of blue and green water. The results showed that the average annual precipitation in the basin was 931 mm, which was the sum of the quantity of blue and green water resources; the annual average of the quantity of blue water resources was 386 mm, accounting for 41.5% of the precipitation, and that of green water resources was 545 mm, accounting for 58.5% of the precipitation. As a whole, precipitation and green water resources presented an upward trend in the period of 1981-2020; whereas blue water resources showed a downward trend. Blue water resources was 165.61, 456.71 and 643.70 mm in very low, normal and very high flow years, respectively, and green water coefficient varied greatly in the typical years. The spatial distribution characteristics of blue water resources, green water resources and precipitation within the basin were similar, showing a spatial pattern of first decreasing and then increasing from the upstream to the downstream, and less in the west but more in the east.