干旱区生态环境知识资源中心

Land-atmosphere interactions in the northwest arid and semi-arid areas of China are important because of their influence on energy exchange at both regional and global scales. In this paper, regular meteorological observations, as well as flux eddy covariance methods, are used to measure land-atmosphere energy exchange. Experiments were conducted over the Dunhuang Gobi, a typical arid region of northwest China, during the summer of 2008. Surface fluxes were measured directly using an eddy-correlation system, while the vertical gradients of wind and temperature were also observed at four levels using a meteorological tower. Based on the observation data, the integral mean of surface albedo over the Gobi was found to be 0.238. In addition, the mean values of momentum, heat roughness lengths, and soil thermal conductivity were, 0.045, 0.005 cm, 0.199 and 0.201 W (m K)(-1), respectively. The Monin-Obukhov similarity functions for momentum and heat were analyzed and new empirical formulae were developed.