State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, 100038, China.
Tsinghua University, Beijing, 100084, China.
Environ Sci Pollut Res Int. 2024 Mar;31(15):22395-22409. doi: 10.1007/s11356-024-32562-0. Epub 2024 Feb 26.
Cold regions are particularly vulnerable to climate change. Thus, evaluating the response of water quality evolution to climate change in cold regions is vital for formulating adaptive countermeasures for pollution control under changing climatic conditions. Taking the Songhua River Basin (SRB) in Northeast China as the target area, we designed a water-heat-nitrogen coupled model based on the principle of water and energy transfer and nitrogen cycle processes model (WEP-N) in cold regions. The impact of climate change on pollution load and water quality was analyzed during the freezing, thawing, and non-freeze-thaw periods by taking the sudden change point (1998) of precipitation and runoff evolution in the SRB as the cut-off. The ammonia nitrogen load at Jiamusi station, the outlet control station in the SRB, was decreased by 1502.9 t in the change period (1999-2018) over the base period (1956-1998), with a - 9.2% decrease due to climate change. Compared to the ammonia nitrogen load during the base period, the ammonia nitrogen load decreased by - 171.3, - 506.9, and - 824.8 t during the freezing, thawing, and non-freeze-thaw periods, respectively, while the coefficient of variation showed an increasing trend during three periods, especially during the freezing and thawing periods. However, the water quality changes differed among periods owing to varying runoff during the year. Meanwhile, increasing runoff and decreasing ammonia nitrogen load improved water quality at Jiamusi station during the freezing period. During the thawing and non-freeze-thaw period, the water quality deteriorated due to the decrease in runoff more than the decrease in ammonia nitrogen load. Hence, the impact of climate change on water quality during thawing and non-freeze-thaw periods should be monitored to potentially offset the human influence on pollution control. The difference in the rate of change of the proportion of Class IV water between the two models with or without the soil freeze-thaw mechanism was 15.9%. The result shows that the application of a model that does not consider the freeze-thaw mechanism might slightly exaggerate the impact of climate change on water quality.
寒冷地区特别容易受到气候变化的影响。因此，评估寒冷地区水质演变对气候变化的响应对于制定气候变化条件下污染控制的适应性对策至关重要。以中国东北地区的松花江流域 (SRB) 为研究区域，我们根据水热氮耦合原理和寒冷地区氮循环过程模型 (WEP-N) 设计了一个水热氮耦合模型。以 SRB 降水和径流量演变的突变点 (1998 年) 作为截止点，分析了冰冻期、融冰期和非冰冻期气候变化对污染负荷和水质的影响。在变化期 (1999-2018 年) 内，松花江流域出口控制站佳木斯站氨氮负荷较基准期 (1956-1998 年) 减少 1502.9 吨，减少了 9.2%。与基准期相比，冰冻期、融冰期和非冰冻期氨氮负荷分别减少了-171.3、-506.9 和-824.8 吨，而变异系数在三个时期均呈上升趋势，尤其是在冰冻期和融冰期。然而，由于年内径流量的变化，水质变化在不同时期有所不同。同时，由于增加了径流量和减少了氨氮负荷，在冰冻期提高了佳木斯站的水质。在融冰期和非冰冻期，由于径流量减少超过氨氮负荷减少，水质恶化。因此，应监测气候变化对融冰期和非冰冻期水质的影响，以潜在抵消人类对污染控制的影响。考虑或不考虑土壤冻融机制的两个模型中，IV 类水质比例变化率的差异为 15.9%。结果表明，应用不考虑冻融机制的模型可能会略微夸大气候变化对水质的影响。
