The Surface Energy Balance Of Austre Lovénbreen Glacier,Arctic

The ice/snow-air interaction process in the Arctic region is a key scientific issue which restricts our understanding of the rapidly change of Arctic region.The glacier is an essential component of the cryosphere elements.Therefore,the research of glacier surface energy balance（SEB）in the Arctic region will help to further explore the ice/snow-air interaction,and more accurately predict the Arctic and global climate.We use the meteorological data obtained by the automatic weather station on the Austre Lovénbreen glacier located at the 337 m a.s.l.from 30 April 2014 to 30 April in 2015.The applicability of downward longwave radiation parameterization schemes and reanalysis data was evaluated through the meteorological data from AWS in this area.The energy components of the Austre Lovénbreen glacier during the study period were calculated through surface energy balance model and their changes were analyzed.Finally,by using the reanalysis data to analyze the changes in the 850 hPa geopotential height and sea level pressure field of the Svalbard Archipelago during the observation period,the impact of warm and moist air intrusion on the surface energy balance of the Austre Lovénbreen glacier was discussed.This study mainly draws the following conclusions:1)Through the evaluation of the downward longwave radiation parameterization scheme,it is found that almost all parameterization schemes have an overestimation of downward longwave radiation.The Bolz’s（1949）all-sky parameterization scheme based on Maykut’s（1973）clear-sky parameterization scheme has the best simulation performance(The Root Mean Square Error is the smallest(RMSE=13 W m^-2),and the Nash-Sutcliffe Efficiency Coefficient is the highest（NSE=0.92）).In the ERA-5 reanalysis data,meteorological elements except air temperature and downward longwave radiation,such as wind speed and air pressure are all overestimated.In general,the ERA-5 reanalysis data can better supplement the missing meteorological data in AWS observations.By comparing the observed and simulated of the cumulative surface mass balance of the Austre Lovénbreen glacier from June to August 2014,it is found that the energy balance model has a better simulation effect on the Austre Lovénbreen glacier.2)The composition of the surface energy balance of the Austre Lovénbreen glacier from 30April 2014 to 30 April 2015,net shortwave radiation（S）was the major energy input,followed by sensible heat flux（H）,and the subsurface heat flux was the smallest energy input;net longwave radiation（L）was a major output,melt energy（Q_m）was the second output,and the smallest output was the latent heat flux（LE）.3)A comparison of the surface energy budget with typical glacier/ice sheet in other regions shows that there are very significant differences between the Arctic and Antarctic,Tibet Plateau regions in the surface energy budget:the net shortwave/longwave radiation in polar region is lower than the Tibet Plateau,the sensible heat and latent heat fluxes of polar region are higher than the Tibet Plateau,the melt energy is zero due to lower surface temperature in Antarctic inland.This difference not only depends on the air/surface temperature,location and albedo and altitude,the effect of warm and humid air intrusion is also very significant.4)An analysis of the 850 hPa geopotential height and sea level pressure field changes in the area north of 65°N with the changes in meteorological data concludes that the meteorological variables of the Austre Lovénbreen glacier to appear warm state when invaded by warm and moist air from the North Atlantic.During the invasion,the net longwave radiation and subsurface heat flux of the Austre Lovénbreen glacier are increased,and the sensible heat and latent heat flux are decreased,but the increment of net longwave radiation and subsurface heat flux is higher than the decrement of turbulent flux.In general,during the invasion,the surface energy loss of the Austre Lovénbreen glacier was decreased,that is the surface energy input of ice/snow was increased.