The Distribution Of Surface Energy Flux In Taklimakan Desert Based On CLM

The Taklimakan Desert has unique atmosphere and atmosphere interactions,and has a different atmospheric boundary layer structure than other regions.It plays an important role in China's weather,climate,and environmental system,and largely affects the formation of the climate in the arid region of Northwest China and the East Asian monsoon.Therefore,studying the energy flux and radiation budget in the Taklimakan Desert is making the great of significance for understanding the energy,water vapor cycle and climate change in the arid region of Northwestern China.The land models provide the basic tools for the study of surface energy fluxes at the regional scale,and the development of data assimilation systems and other remote sensing technologies provides the basic data required by land surface models.Therefore,in this paper,firstly,we verified the accuracy of ERA5 data of ECMWF and GLDAS data,and then used the two atmospheric forcing data to drive CLM 3.5 land model,obtained the simulation results of the net radiant flux,the land surface temperature,the sensible heat flux,the latent heat flux and the surface soil heat flux in the Taklimakan Desert and surroundings from January to December in 2013.After calculating out the accuracy,the main conclusions are as follows:(1)In the Tazhong Desert,The air temperature,relative humidity and atmospheric pressure data of ERA5 and GLDAS are in good agreement with the measured values of the site station,with a high R~2 and small errors,and high accuracy,but the accuracy of the wind speed data is slightly worse;(2)Comparing the two simulation results of CLM?ERA5 and CLM?GLDAS,as a whole,the two simulation results have the same variety trends,that is,the maximum values of net radiant flux,surface temperature,and sensible heat flux appear in the summer period,and the minimum value in winter,spring is the rising period,and autumn is the falling period.the monthly average temperature of the surface temperature in summer is above 30?,while the average value in winter is very small and all are below 5?,The annual average is 16.51?;The monthly average of the net radiant flux in the Tazhong area is very high,with a value of about 90 W/m~2,and it is very small in winter,all around 10 W/m~2.The annual average volume is 50.53 W/m~2;the sensible heat flux is above 15 W/m~2 throughout the year,and the monthly average in summer is the largest,with the average value above 55 W/m~2.The annual average is34.00 W/m~2;the monthly average surface heat flux is very small,not exceeding 10W/m~2.The monthly average in winter is lower than 0 W/m~2,the monthly average value from March to September is above 0 W/m~2,and the annual average surface heat flux is1.10 W/m~2.(3)From the perspective of spatial distribution,the two simulation results can also reflect the change of different LUCCs(land use and land cover change).The simulation results in the desert area are significantly different from other LUCCs.The surface temperature is the highest in the oasis area surrounding the desert.,Followed by the desert hinterland,and the mountain ice sheet area has the lowest surface temperature;the change of net radiation flux is related to the surface albedo,which shows that the net radiation of the water body is the largest,the bare soil and desert areas are the second,and the alpine ice sheet areas are the smallest;The monthly average change of the latent heat flux and the surface soil heat flux in the desert area is very small,and the monthly average is also very small,but the latent heat flux in the desert area is greatly affected by precipitation.When there is precipitation,the latent heat flux increases suddenly;(4)Through the verification of the simulation results of CLM?ERA5 and CLM?GLDAS at the tower station,the accuracy values of these two simulation results are show that:the best result is the surface temperature,followed by the net radiant flux,then the sensible heat flux,and the surface soil heat flux result is the worst.The simulation results of CLM?ERA5 and CLM?GLDAS show that the R~2 of the surface temperature are 0.99,the R~2 of the net radiant flux have reached 0.86 and 0.83,and the R~2 of the sensible heat flux are 0.68 and 0.77,but the errors of the surface soil heat flux results are larger.Due to the extreme water shortage in the Taklimakan Desert and the lack of latent heat flux measured data,the results of the latent heat flux simulation have not been verified.In general,CLM?ERA5 simulation results are better than CLM?GLDAS in the Tazhong Desert,which also shows that the higher the accuracy of the forcing data,the better the simulation results.