Responses of annual and seasonal streamflow to climate change in the Lena River basin in Arctic region
Streamflow from the Lena River is one of the major sources of freshwater in the Arctic Ocean and has a significant impact on the Arctic atmosphere,sea ice thermal processes and ocean thermohaline circulation.In recent years,streamflow in the Lena River basin is changing significantly with intensified global warming.In order to investigate the response of streamflow to climate change in the Lena River basin,the study firstly analyzed the trends of precipitation,air temperature and streamflow in the basin from 1975 to 2014 using the M-K trend test.Then,we constructed the abcd-cr hydrological model by considering a coupled snowmelt and permafrost module.Based on the abcd-cr model,we simulated climatic scenarios and quantitatively estimated the relative changes of annual and seasonal streamflow and the elasticities of annual and seasonal streamflow to changes in air temperature and precipitation respected to different climate scenarios.Results showed that:(1)Both the annual and seasonal air temperatures in the Lena River showed increasing trends from 1975 to 2014;The annual,summer,and autumn precipitation presented increasing trends while the spring and winter precipitation showed decreasing trends;The annual,spring,autumn,and winter streamflow had significant increasing trends while the summer streamflow showed a non-significant decreasing trend.(2)The climate scenario simulation results quantified the variations in annual and seasonal streamflow resulting from changes in precipitation and air temperature.(3)The results of sensitivity analysis showed that annual streamflow increases with the increase of precipitation and decreases with the increase of air temperature;The impact of precipitation change on seasonal streamflow is similar to that of annual streamflow change.However,the impacts of air temperature varied in different seasons.Specifically,the relative change of summer streamflow is the largest,while that of winter streamflow is the smallest.The impact of air temperature on seasonal streamflow is more complex than that of annual streamflow due to the interactions between seasonal evaporation and freeze-thaw processes.With increasing air temperature,spring streamflow increases,while streamflow in other seasons decreases.
Lena Riverstreamflowclimate changeabcd-cr modelsensitivity
万方数据
维普
