The characteristics of spatial disturbance of surface processes in oasis on the background of desert
夏季绿洲生态环境对荒漠背景地表能量过程的扰动

It is main character in arid area in north west China that desert and gobi are essential landscape and the oases are interspersed.Desert and Gobi effect oases, at the same time the desert and gobi also are effected by oases.Using the observational data in "the Field Experiment on Land-atmosphere Interaction over Arid Region of Northwest China" carried out in Dunhuang of Gansu Province,the differences between the surface energy processes in oasis and those in the near Gobi are analyzed,and the character of spatial disturbance of surface energy processes in Oasis eco-system on the Gobi Background were discovered.As a result,it is shown that the mean net radiation flux on oasis is 60 W/m~2 higher than that in near Gobi,and the margin value is one-fourth of mean net radiation flux on oasis.The peak value of effective long-wave radiation is lower 88W/m~2 and its average value is lower 35W/m~2 on a day.The most important contribution of the margin value is lower surface upward long-wave radiation flux on oasis,is 58.3%;the next is higher global solar radiation over oasis, is 42.7%;lower downward long-wave radiation flux on oasis is a opposite contribution to the margin value,and it is unexpected that the surface reflected radiation flux on oasis contribute a bit opposite to the margin value.The latent flux on oasis is ten times and the soil heat flux is three times as high as those on Gobi.But the sensible heat flux is about lower 50% than that in the near Gobi.In the surface heat budget on oasis,the margin value on oasis mainly distributes to enhancing the latent heat flux and ground heat flux in oasis,and its surplus,which includes what lower sensible heat flux over oasis than that on the near Gobi contributes,is occupied by the surface heat energy balance on oasis.The balance may be caused by the vertical heat advection flux,which is almost absent on its surroundings of Gobi and the common region.Now,we know that low albedo,low sensible heat and higher latent heat is character on oasis by contrast with that on Gobi background.These characteristics are important to maintain the oasis eco-system.But such high latent heat means too high evapotranspiration on the Dunhuang oasis and it is show from other side that the eco-system on the oasis is weak.It remind us we should protect our eco-system and environment.