World survey of climatology volume 1A heat balance climatology

Abstract

The Zoige wetland, located in the eastern edge of Qinghai-Tibet Plateau, is highly sensitive to global climate change for its high elevation and cold environment. As one of the major components in the hydrological cycle, evapotranspiration (ET) affects regional water balance and ecosystems in alpine wetlands. To identify the impact of the changes of wetland eco-environment on ET, and to indicate the relation between the real ET and the potential ET, a comparative study on the hourly real ET measured by weighting lysimeters and the hourly potential ET, calculated by the FAO Penman-Monteith equation, has been carried out at three blocks with different surface water levels during three vegetation growth stages in the Zoige wetland. Results show that the hourly potential ET is generally higher than the real ET during the studied period. The hourly ET changed with the variation of the vegetation growth stage, the water level and vegetation characteristics. The hourly potential ET is the largest in the peak growth stage, and the least during the last growth stage for each water level. The real ET is the least at the highest water level for all growth stages. The results suggest that future wetlands management strategies should emphasize the protection of a reasonable vegetation pattern and the basic water demands of ecosystems for improving the wetland ecosystem health in the Zoige wetland.