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Abstract: Four sets of remote sensing images from 1987, 1994, 2000, and 2006, 50 years of meteorological and soil moisture data corresponding to different desertified lands were combined with populations and livestock data to analyze the process and cause of desertification in a portion of the Qinghai–Tibetan Plateau (QTP). It showed that surface soil temperature in the region has increased at an average rate of 0.6 °C per decade between 1980 and 2005, the thawing days on the surface have increased by 60 days from 1983 to 2001, and the depth of the seasonal thawing layer has increased by 54 cm, 102 cm and 77 cm in April, May and June, respectively, from 1983 to 2003. As a result, the upper soil layer has become drier due to the thickening active layer and soil water infiltration. These changes, in turn, have inhibited the growth of alpine meadow vegetation that has shallow root systems. It is concluded that climate warming and permafrost thawing have caused desertification in grazing regions of the Qinghai–Tibetan Plateau (QTP). [Copyright &y& Elsevier]

Partitioning evapotranspiration ( ET ) into soil evaporation ( E a ) and plant transpiration ( T r ) is important to understand response of ecosystem water balance to climate warming. A field experiment was conducted to investigate the effect of additional infrared radiation as a simulation of climate warming (W1: 130 W m −2 and W2: 150 W m −2 ) on ET , E a , T r , and soil moisture in an alpine meadow in the Qinghai-Tibet plateau (QTP). ET was calculated by using an energy balance model and a soil moisture correction function. E a in warm-rainy season was estimated by a multiple linear regression with latent heat, soil moisture in 0–10 cm layer and soil temperature in 20 cm depth as independent variables. T r was quantified as the difference between ET and E a . Results showed that annual ET increased by 92 mm and 89 mm, annual E a increased by 29.12 mm and 33.37 mm, and annual T r increased by 63.53 mm and 55.81 mm in W1 and W2 treatments, respectively. The results suggest that T r stimulation accounts for most of the ET change and is the major reason for the soil surface layer drying in alpine meadow ecosystem on the QTP. [ABSTRACT FROM AUTHOR]