RS Based Evaporation Estimation of Three River Sources in Qinghai-Tibet Plateau and Its Response to Lakes and Wetlands

The changes of lakes and wetlands in the Three River Sources have received many concerns all the time,climate changes is considered as the main factor of the changes of lakes and wetlands.Comparing with the temperature and precipitation,the evaporation data was difficult to acquire from the weather stations,but the RS technology provides a new approach to estimate the regional surface evaporation.Based on the principle of surface energy balance,combining with MODIS data and the meteorological data of the study region,the evaporation estimation model of Three River Sources is established,the distributing rules of evaporation is analyzed,and the correlation relationships among the temperature,precipitation,wind speed and evaporation of the study area are explored,and at the last the response between evaporation and the changes of lakes and wetlands is analyzed.The results show that evaporation of the Three River Sources Presents increasing trend,and it's varied with the difference among conditions of hydrothermal,vegetation cover and altitude;the evaporation of study area was greatly affected by the temperature and precipitation;and the increasing evaporation induces the lake shrinking and wetland degradation.