Processes of runoff in seasonally-frozen ground about a forested catchment of semiarid mountains  

作　　者：PengFei Lin ZhiBin He Jun Du LongFei Chen Xi Zhu QuanYan Tian 

机构地区：[1]Linze Inland River Basin Research Station,Chinese Ecosystem Research Network,Lanzhou,Gansu 730000,China [2]Key Laboratory of Ecohydrology of Inland River Basin,Northwest Institute of Eco‐Environment and Resources,Chinese Academy of Sciences,Lanzhou,Gansu 730000,China

出　　处：《Research in Cold and Arid Regions》2020年第5期272-283,共12页寒旱区科学（英文版）

基　　金：the National Natural Science Foundation of China(Nos.41901044,41621001 and 41701296);the"CAS Light of West China"Program(29Y829861);Foundation for Excellent Youth Scholars of Northwest Institute of Eco‐Environment and Resources,Chinese Academy of Sciences(FEYS2019019).

摘　　要：Climate warming increases the variability in runoff of semiarid mountains where seasonally-frozen ground is widely distributed.However,what is not well understood are the processes of runoff,hydrological drivers,and freeze-thaw cycles in seasonally-frozen ground in semiarid mountains.To understand how freeze-thaw cycles affect runoff processes in seasonally-frozen ground,we monitored hydrological processes in a typical headwater catchment with seasonally-frozen ground in Qilian Mountain,China,from 2002 to 2017.We analyzed the responses of runoff to temperature,precipitation,and seasonally-frozen ground to quantify process characteristics and driving factors.The results show that annual runoff was 88.5 mm accounting for 25.6%of rainfall,mainly concentrated in May to October,with baseflow of 36.44 mm.Peak runoff occurred in June,August,and September,i.e.,accounting for spring and summer floods.Runoff during the spring flood was produced by a mix of rainfall,melting snow,and melting seasonally-frozen ground,and had a significant correlation with air temperature.Runoff was mainly due to precipitation accumulation during the summer flood.Air temperature,average soil temperature at 0−50 cm depth,and frozen soil depth variable explained 59.60%of the variation of runoff in the thawing period,while precipitation variable explained 21.9%.Thawing-period runoff and soil temperature had a>0.6 correlation coefficient(P<0.05).In the rainfall-period,runoff was also affected by temperature,soil moisture,and precipitation,which explained 33.6%,34.1%and 18.1%,respectively.Our results show that increasing temperature and precipitation will have an irreversible impact on the hydrological regime in mountainous basins where seasonally-frozen ground is widely distributed.

关 键 词：RUNOFF seasonally-frozen ground semiarid mountains Northeast margin of Tibetan Plateau 

分 类 号：P333.1[天文地球—水文科学]