Climate Changes in the Tibetan Plateau during the Last Three Decades

The Tibetan Plateau is one of the best places to study global climate change. Aridity or humidity status of land surface is an important outcome that has close relations with a set of climatic factors such as precipitation, temperature, solar radiation, relative humidity and wind, but the relationship between them is complicated. This paper calculated potential evapotranspiration by applying Penman-Monteith model which was recommended by FAO in 1998, and aridity index by Vyshotskii model to indicate aridity or humidity status of the Tibetan Plateau during the period 1971-2000. Then it analyzed the changing trends of observed climatic factors (temperature and precipitation) and calculated factors (potential evapotranspiration and aridity index), and showed the spatial distribution of aridity/humidity status over the Tibetan Plateau during the period 1971-2000. Trends calculated by linear regression were tested through Mann-Kendall test. Results of 77 meteorological stations on the Tibetan Plateau showed that the main trends of climate change are temperature rise and precipitation increase; potential evapotranspiration decrease and most of the areas was ascending to more humid status. Results suggested that aridity or humidity status cannot be presented only with precipitation.