A research team led by Prof. MA Yaoming from the Institute of Tibetan Plateau Research (ITP) of the Chinese Academy of Sciences has proposed a reliable lake evaporation estimation method based on meteorological and satellite data.
They estimated that the annual water evaporation of the lakes on Tibetan Plateau was 51.7 billion tons, which equals to the water volume of 3570 West Lakes in Hangzhou, China.
The Tibetan Plateau (TP) is considered as the "Asian Water Tower" and its lake area is nearly 50000 square kilometers, accounting for more than 50% of China’s total lake area.
Due to the scarcity of in-situ measurements over lakes on TP, the evaporation amounts over a same lake are inconsistent. The spatial distributions and total amounts of the evaporation over these high-elevation lakes have never been reported.
The research team presented a plausible hypothesis of energy balance during the ice-free seasons. They explored the multiyear average ice phenology and the evaporation amounts of 75 large dimictic lakes by using a combination of satellite products, CMFD forcing data and in-situ measurements of Tibetan Observation and Research Platform (TORP) stations.
"The results showed acceptable consistency with in-situ measurements of several high-elevation lakes," said Prof. MA.
The total annual water evaporation amounts were 29.4±1.2 billion tons for the 75 studied lakes, and 51.7±2.1 billion tons for all plateau lakes included.
Sublimation during the winter season approximately accounted for 12.3-23.5% of the annual water evaporation amounts of these high-elevation lakes, which is also an important component for lakes’ water balance analysis.
Evaporation amounts showed large variability in spatial distributions, with a pattern of higher values in the south.
"The proposed method can accurately estimate water evaporation amounts of large lakes, providing a reference data for lakes’ water balance analysis," said Prof. MA.
This research was supported by the Second Tibetan Plateau Scientific Expedition and Research Program, the Strategic Priority Research Program of Chinese Academy of Sciences, and the National Natural Science Foundation of China.