沙漠腹地人工绿地地表能量交换特征

Characteristics of surface energy exchange in the artificial shelter forest land of the hinterland of Taklimakan Desert

运用涡度相关法开路系统对塔克拉玛干沙漠腹地人工灌溉绿地生长季地表能量交换特征以及与环境因子的关系进行测定分析。结果表明:在典型晴天条件下,无论是沙漠区还是沙漠腹地灌溉绿地,白天感热通量在净辐射通量的分配中所占的份额最大,潜热交换仅占很小的比例,人工绿地感热通量和潜热通量的峰值为230.54 W/m^2和88.5 W/m^2,沙漠区为220 W/m^2和17.55 W/m^2,沙漠腹地人工灌溉造林后潜热交换明显增加。沙漠腹地造林后,绿地波文比日变幅和日均波文比均减小,绿地日均波文比为沙漠区的15%,人工绿地的营建促使了局地气候的改变。绿地地表能量交换受气象因子和下垫面条件的影响和制约,按相关系数的高低,环境因子对感热、潜热通量的影响依次为:R_n>△T_a>△T_S>v>T_S,沙漠区人工造林后地表能量交换与多个环境因子有着密切的关系。这些研究结果将加深我们对沙漠地区人工灌溉造林地近地层能量交换的认识。

In order to reveal the energy exchange characters of artificial irrigated shelter forest land near the ground surface in the hinterland of the Taklimakah Desert. The research applied the Eddy Covariance Method to measure sensible heat and latent heat flux on a typical clear day in growing reason. The results showed as follows ： （ 1 ） Sensi- ble heat flux is a larger proportion of energy and latent heat flux accounts for a small proportion in the desert and ar- tificial shelter forest land. However the latent heat flux in artificial shelter forest land is more than that in desert be- cause of the surface albedo, soil moisture and land cover change after afforesting the shelter-forests. Compared with the desert, the heat flux and latent heat flux peak increase accordingly in artificial irrigated shelter forest land, the peak of latent heat and sensible heat flux are 230.54 W/m2 and 88.5 W/ms in artificial shelter forest land, thus the desert area is 220 W/ms and 17.55 W/m2, the surface energy exchange characteristics in the hinterland of the Takli- makan Desert is similar with other arid areas in northwest China. （2）Average Bowen value is 1.63 in artificial irri- gated shelter forest land whereas 10.82 in desert on a typical clear day. After afforesting, average Bowen value and Bowen diurnal range is significantly reduced, only occupied 15% of the desert area, the Bowen in artificial irrigated shelter forest land is similar with oasis in the Northwest China. This proves that microclimate had prompted. （3） Me- teorological factors and underlying surface influence surface energy exchange in artificial irrigated shelter forest land. The correlation analysis showed that the order of fitness degree between latent heat and sensible heat flux and single environment factor was ： net radiation 〉 variety of air temperature 〉 variety of soil temperature 〉 wind veloci- ty 〉 soil temperature. The surface energy exchange is closely related to several environmental factors. The result will show the characteristics of surface energy exchange of irrigated afforestation in the desert hinterland.