Micrometeorological changes following establishment of artificially established artemisia vegetation on desertified sandy land in the Horqin sandy land, China and their implication on regional environmental change

Human-induced desertification in the Horqin sandy land in the northeastern part of China has been reversed since the mid-1970s through revegetation. This land cover change affects surface energy and water transfer processes. We employed the Bowen ratio energy balance technique to examine micrometeorological changes following the establishment of artificially established artemisia vegetation on the severely desertified sandy land in Naiman, a county located in the Horqin. Re-vegetation on the desertified sandy land decreased the surface albedo and increased the surface roughness length, thereby resulting in considerable changes in both surface water and heat budget, and wind regimes. As compared with that (34%) before. re-vegetation, albedo decreased by 15% as the sandy land was semi-fixed and decreased by 47% as the sandy land is entirely fixed. With change in albedo, partitioning of the available energy exhibited distinct patterns depending on vegetation cover, especially large increase in evapotranspiration, which may result in soil desiccation and thus further affecting temperature regime. Establishment of artificially established vegetation also affected wind regimes by altering surface roughness; consequently, erosion was avoided in the vegetated surfaces. These changes, if occurring in large spatial scale, may affect the local and regional climate according to the Charney theory. (C) 2002 Elsevier Science Ltd.