未来气候变化影响下的流域面源污染负荷特征响应评估

Estimation of feature response of watershed nonpoint source pollution load under influence of future climate change

针对流域面源污染负荷在未来气候变化影响下的变化特征,以我国新安江上游率水流域为例,使用通用流域污染负荷模型(GWLF),对其2000-2013年的水量及总氮、总磷面源污染负荷通量进行了模拟,并解析了其负荷来源分配。在此基础上,基于政府间气候变化专业委员会(IPCC)的气候变化评估报告结果,利用GWLF模型分析了到21世纪20年代、50年代、80年代在A1FI(最高排放)和B1(最低排放)情景下,率水流域的水文及总氮、总磷面源污染负荷特征变化。结果表明:未来气候变化对流域水文及面源污染负荷特征均有一定影响。年水资源量先减少后增加,地表径流量和蒸发量逐渐上升而地下水量逐渐下降。到2080s,A1FI情景比B1情景有更多的水资源量。年总氮通量先增加后减少,在2050s最高,而年总磷通量则逐渐增加,且两种污染物均在A1FI排放情景下有更高的污染负荷量,表明人类温室气体的排放会潜在地增加流域水体面源污染负荷。

The feature of watershed non-point source pollution load response under the influence of future climate change are paid close attention. Taking Shuaishui watershed which locates in the upstream of Xin＇an River for example,the paper used generalized watershed loading function（ GWLF） model to simulate the nonpoint source pollution load flux of stream flow and TN and TP from 2000 to 2013,and analyzed the allocation of load source. On this basis,the validated GWLF model was used to estimate the changes of stream flow and TN and TP loads in 2020 s,2050s,and 2080 s under A1FI（ highest future emission trajectory） and B1（ lowest future emission trajectory） scenarios based on intergovernmental panel on climate change（ IPCC） ＇s assessment report. The results show that the future climate change has certain effect on both watershed hydrologic process and non-point pollution loads. The annual amount of water resources first increases and then decreases while the runoff and evaporation gradually increase and the groundwater gradually decrease. Up to 2080 s,there will be more water resources under A1 FI scenario than that under B1. The annual TN flux also first increase with highest pressure in 2050 s and then decrease,and the annual TP flux gradually increases. Both TN and TP have higher loads under A1 FI,which indicated that theemissions of greenhouse gases from human activities would potentially increase watershed non-point source pollution load.