Impacts of permafrost degradation on streamflow in the northern Himalayas  

作　　者：Linfeng FAN Fang JI Xingxing KUANG Zhilin GUO Rui ZHANG Chunmiao ZHENG 

机构地区：[1]State Key Laboratory of Mountain Hazards and Engineering Resilience,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610299,China [2]Yangtze Institute for Conservation and Development,Hohai University,Nanjing 210024,China [3]School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [4]Eastern Institute for Advanced Study,Ningbo 315200,China

出　　处：《Science China Earth Sciences》2024年第6期1990-2000,共11页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.92047202);the Hundred Talents Program of the Chinese Academy of Sciences;the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-03)。

摘　　要：The Himalayan water tower provides crucial water resources for Asia.Permafrost degradation is deemed to exert important impacts on streamflow in the Himalayan rivers.Yet,the magnitudes of such impacts remain poorly quantified.Here,we established a robust hydrological model that incorporated active layer deepening and ground ice melt for the drainage basin of the largest river in the northern Himalayas-the Yarlung Zangbo River(YZR).We estimated that permafrost degradation led to~0.65 km^(3)/yr decrease in surface runoff and~0.35 km^(3)/yr increase in baseflow and ground ice melt contributed~0.25% to the annual streamflow in the YZR for the period 2001-2022.The“fill-and-spill”mechanism helps explain the seeming contradiction of observed increasing versus decreasing baseflow in different permafrost regions worldwide.We propose that the dilution of riverine dissolved organic carbon(DOC)concentrations by baseflow may lead to the riverine DOC hysteresis patterns.This study not only lays solid scientific basis for water resources management in the Himalayas,but also yields new insights into how to interpret measured river discharge and nutrient flux in permafrost regions over the globe.

关 键 词：Permafrost degradation HYDROLOGY Streamflow Surface runoff GROUNDWATER HIMALAYAS 

分 类 号：P343.1[天文地球—水文科学] P642.14[天文地球—地球物理学]