A Study of Computing the Surface Flux in the Typical Arid Region of Northwest China by a Variational Method
利用变分法计算西北典型干旱区地表通量的研究

By using the data observed during the intensive observation period of the Dunhuang Land-Surface Process Field Experiment (DLSPFE) from May through June in 2000, a variational method is applied to compute surface fluxes of sensible and latent heat over Gobi in the typical arid region of Northwest China. In comparison with the conventional Bowen ratio energy balance (BREB) method, by making fuller and more complete use of the information provided by the observational data and by the surface energy balance equation and the similarity profile equations, the variational method solves the problem that the BREB method becomes computationally unstable and produces spurious large values when Bowen ratio is in the vicinity of -1. The fluxes and bulk transport coefficients computed by the variational method are more rational and stabler than those of the BREB.