State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No.4888, Shengbei Street, Changchun, 130102, China; Institute of Water Conservancy and Electric Power, Heilongjiang University, Harbin, 150080, China.
Institute of Water Conservancy and Electric Power, Heilongjiang University, Harbin, 150080, China.
J Environ Manage. 2024 Oct;369:122292. doi: 10.1016/j.jenvman.2024.122292. Epub 2024 Sep 3.
Global warming is profoundly impacting snowmelt runoff processes in seasonal freeze-thaw zones, thereby altering the risk of rain-on-snow (ROS) floods. These changes not only affect the frequency of floods but also alter the allocation of water resources, which has implications for agriculture and other key economic sectors. While these risks present a significant threat to our lives and economies, the risk of ROS floods triggered by climate change has not received the attention it deserves. Therefore, we chose Changbai Mountain, a water tower in a high-latitude cold zone, as a typical study area. The semi-distributed hydrological model SWAT is coupled with CMIP6 meteorological data, and four shared socioeconomic pathways (SSP126, SSP245, SSP370, and SSP585) are selected after bias correction, thus quantifying the impacts of climate change on hydrological processes in the Changbai Mountain region as well as future evolution of the ROS flood risk. The results indicate that: (1) Under future climate change scenarios, snowmelt in most areas of the Changbai Mountains decreases. The annual average snowmelt under SSP126, SSP245, SSP370, and SSP585 is projected to be 148.65 mm, 135.63 mm, 123.44 mm, and 116.5 mm, respectively. The onset of snowmelt is projected to advance in the future. Specifically, in the Songhua River (SR) and Yalu River (YR) regions, the start of snowmelt is expected to advance by 1-11 days. Spatially, significant reductions in snowmelt were observed in both the central part of the watershed and the lower reaches of the river under SSP585 scenario. (2) In 2021-2060, the frequency of ROS floods decreases sequentially for different scenarios, with SSP 126 > SSP 245 > SSP 370 > SSP 585. The frequency increments of ROS floods in the source area for the four scenarios were 0.12 days/year, 0.1 d/yr, 0.13 days/year, and 0.15 days/year, respectively. The frequency of high-elevation ROS events increases in the YR in the low emission scenario. Conversely, in high emission scenarios, YR high-elevation ROS events will only increase in 2061-2100. This phenomenon is more pronounced in the Tumen River (TR), where floods become more frequent with increasing elevation.
全球变暖正在深刻影响季节性冻融区的冰雪融水径流过程，从而改变雨雪混合（ROS）洪水的风险。这些变化不仅影响洪水的频率，还改变水资源的分配，这对农业和其他关键经济部门都有影响。尽管这些风险对我们的生命和经济构成了重大威胁，但气候变化引发的 ROS 洪水风险尚未得到应有的重视。因此，我们选择长白山作为高纬度寒冷地区的一座“水塔”作为典型研究区。半分布式水文模型 SWAT 与 CMIP6 气象数据耦合，经过偏差修正后选择了四个共享社会经济路径（SSP126、SSP245、SSP370 和 SSP585），从而量化了气候变化对长白山地区水文过程的影响以及 ROS 洪水风险的未来演变。结果表明：（1）在未来的气候变化情景下，长白山大部分地区的冰雪融化量减少。在 SSP126、SSP245、SSP370 和 SSP585 下，年平均冰雪融化量预计分别为 148.65mm、135.63mm、123.44mm 和 116.5mm。未来冰雪融化的开始时间预计会提前。具体来说，在松花江（SR）和鸭绿江（YR）流域，冰雪融化的开始时间预计会提前 1-11 天。在流域中部和河流下游，在 SSP585 情景下，冰雪融化量显著减少。（2）在 2021-2060 年，不同情景下 ROS 洪水的频率依次降低，SSP126＞SSP245＞SSP370＞SSP585。四个情景下 ROS 洪水的频率增量分别为 0.12 天/年、0.1 天/年、0.13 天/年和 0.15 天/年。四个情景下，源头区的 ROS 洪水频率增加，在低排放情景下，YR 高海拔 ROS 事件的频率增加。相反，在高排放情景下，YR 高海拔 ROS 事件仅在 2061-2100 年增加。这种现象在图们江（TR）更为明显，随着海拔的升高，洪水的频率越来越高。
