Impacts of permafrost thaw on streamflow recession in a discontinuous permafrost watershed of northeastern China
Impacts of permafrost thaw on streamflow recession in a discontinuous permafrost watershed of northeastern China
复制标题
多年冻土融化对东北不连续多年冻土流域径流衰退的影响
DOI：
10.1016/j.scitotenv.2022.157624
复制
发表时间：
2022-07-29
影响因子：
9.8
通讯作者：
Cai, Tijiu
中科院分区：
文献类型：
--
作者：
Feng, Xinyue;Duan, Liangliang;Cai, Tijiu
气候变化导致的永久冻土融化正在通过增加泛北极地区的地面水力传导性以及地表和地下水文连通性来改变陆地水文过程。了解径流如何响应由永久冻土融化引起的水文过程和条件的变化，对于高纬度和高海拔地区的水资源管理至关重要。在本研究中，我们分析了位于欧亚大陆多年冻土区南缘的塔河流域1964-2016年的流量衰退特征。结果表明，径流退化与多年冻土退化之间存在联系，这一点由径流统计分析和模拟的地面变暖和活动层增厚所表明。1972 ~ 2020年，由于气候变暖加剧，东北地区5、40、100和200 cm深度的退缩常数和活动层温度显著增加。季节性活动层解冻开始时间提前10 d，模拟活动层厚度在此期间增加了54 cm。从暖期（1972-1988）到解冻期（1989-2016），平均年流量衰退时间增加了11.5天（+ 53%），这些时间由断点分析确定。这些水文变化源于集水区蓄水量的增加，并与活动层厚度的增加和季节性解冻期的延长有关。这些结果表明，多年冻土退化可以显著延长不连续、零星和孤立的多年冻土下的流域的衰退流持续时间，从而改变欧亚多年冻土区南缘的洪水动态和水资源。
Permafrost thaw due to climate change is altering terrestrial hydrological processes by increasing ground hydraulic conductivity and surface and subsurface hydrologic connectivity across the pan-Arctic. Understanding how runoff responds to changes in hydrologic processes and conditions induced by permafrost thaw is critical for water resources management in high-latitude and high-altitude regions. In this study, we analyzed streamflow recession characteristics for 1964-2016 for the Tahe watershed located at the southern margin of the permafrost region in Eurasia. Results reveal a link between streamflow recession and permafrost degradation as indicated by the statistical analyses of streamflow and the modeled ground warming and active layer thickening. The recession constant and the active layer temperatures at depths of 5, 40, 100, and 200 cm simulated by the backpropagation neural network model significantly increased during the study period from 1972 to 2020 due to intensified climate warming in northeastern China. The onset of seasonal active layer thaw was advanced by 10 days, and the modeled active layer thickness increased by 54 cm in this period. The average annual streamflow recession time increased by 11.5 days (+ 53 %) from the warming period (1972-1988) to the thawing period (1989-2016), with these periods determined from breakpoint analysis. These hydrologic changes arose from increased catchment storage and were correlated to increased active layer thickness and longer seasonal thawing periods. These results highlight that permafrost degradation can significantly extend the recession flow duration in a watershed underlain by discontinuous, sporadic, and isolated permafrost, and thereby alter flooding dynamics and water resources in the southern margin of the Eurasian permafrost region.