Evaporation Estimation Of Lake Area In Badain Jaran Desert

As one of the most important part of regional hydrological cycle,evaporation is also a significant factor of regional heat balance.It is necessary to have evaporation accurately measured,so that better research can be done on global climate and environment and the development of water resources and protection of the wetland ecosystem.There are many ways to estimate evaporation.For example,measuring and converting with evaporation pan,water balance and calculating with empirical formula.Badan Jaran Desert,with an area of 52000 km2 and an elevation of 1150?1700m,is located in the Alashan Plateau.Precipitation in the south area is more than that in the north.There are 144 lakes distributed in the southeast of the desert between the megadunes,and 74 of them have water all year round.Based on modified Surface Energy Balance System,the evaporation of the Sumu Jaran South Lake,in the southeast of Badain Jaran Desert,was estimated from 2000 to 2013 using TM/ETM+ data.The improvements of the SEBS model were as follows:1.The spatial resolution was upgraded from 250m*250m for MODIS to 30m*30m for TM/ETM+ data;2.The mono-window algorithm put forward by Qin Zhihao was used to calculate the surface temperature of the lake;3.Algorithm proposed by Liang Shunlin was used to estimate the broad band albedo in this area.The result was validated by the E601 pan observation evaporation in the Sumu Jaran South Lake.It is indicated that SEBS result was strongly correlated with pan observation and R2 is more than 0.95(RMSE=0.313mm,and MAPE=8.17%).A conversion equation was coming out with the conversion coefficient was 0.621.Based on the equation,the annual evaporation of the lake is 1287.544mm.The correlations between evaporation and meteorological factors were also discussed in this paper.Temperature and sunshine hours were strongly correlated with evaporation,whereas wind speed had the least correlation with evaporation.