Ocean contributes to the melting of the Jakobshavn Glacier front  

作　　者：Kaijia WANG Xiao CHENG Zhuoqi CHEN Fengming HUI Yan LIU Ying TIAN 

机构地区：[1]College of Global Change and Earth System Science,Beijing Normal University,Beijing 100875,China [2]School of Geospatial Engineering and Science,Sun Yat-Sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China [3]University Corporation for Polar Research,Beijing 100875,China

出　　处：《Science China Earth Sciences》2020年第3期405-411,共7页中国科学（地球科学英文版）

基　　金：supported by the National Key R&D Program of China (Grant No. 2018YFC1406101);the Fundamental Research Funds for the Central Universities

摘　　要：The Jakobshavn Glacier(JG)in Greenland is one of the most active glaciers in the world.It was close to balance before 1997 but this was followed by a sudden transition to rapid thinning.The reason for the change remains unclear.In this study,The NASA Pre-IceBridge ice thickness data are collected to monitor the melting of JG front.The surface elevation decreased by around 90 m from 1995 to 2002 on the floating front.A distributed energy balance model is developed to estimate the energy balance of JG front in the past 30 years(1986-2016).The results indicate that multi-year average energy fluxes absorbed by the floating front of JG from the ocean were about 500 Wm^-2 from 1986 to 2016.This is approximately two times of the energy fluxes from atmosphere during the same period.The energy fluxes from the ocean increased from 200 to 600 Wm^-2during the period from 1990 to 1998 while energy fluxes from the atmosphere remained stable at about 250 Wm^-2.These results demonstrate that ocean contributes more to the melting of the JG front,and suggest that bottom surface melting must have a profound influence on marine-terminating glacier dynamics.The Jakobshavn Glacier (JG) in Greenland is one of the most active glaciers in the world.It was close to balance before 1997 but this was followed by a sudden transition to rapid thinning.The reason for the change remains unclear.In this study,The NASA Pre-IceBridge ice thickness data are collected to monitor the melting of JG front.The surface elevation decreased by around 90 m from 1995 to 2002 on the floating front.A distributed energy balance model is developed to estimate the energy balance of JG front in the past 30 years (1986-2016).The results indicate that multi-year average energy fluxes absorbed by the floating front of JG from the ocean were about 500 W m 2 from 1986 to 2016.This is approximately two times of the energy fluxes from atmosphere during the same period.The energy fluxes from the ocean increased from 200 to 600 W m 2during the period from 1990 to 1998 while energy fluxes from the atmosphere remained stable at about 250 W m 2.These results demonstrate that ocean contributes more to the melting of the JG front,and suggest that bottom surface melting must have a profound influence on marine-terminating glacier dynamics.

关 键 词：Jakobshavn Glacier Front thinning Energy balance Greenland glaciers Ocean forcing 

分 类 号：P343.6[天文地球—水文科学]