Difference and cause analysis of water storage changes for glacier-fed and non-glacier-fed lakes on the Tibetan Plateau.

Abstract

Lakes on the Tibetan Plateau are very sensitive to climate change and have expanded rapidly in recent decades. In this study, lake water storage change (LWSC) of 150 lakes since 1976 was estimated based on multi-temporal Landsat images and Shuttle Radar Topography Mission data. The lakes were then separated into glacier-fed and non-glacier-fed lakes based on the second Chinese glacier inventory and basin boundaries. The results indicate that most lakes had a shrinking trend and total water storage decreased by 5.53 ± 0.4 km3 from 1976 to 1990; however, most lakes expanded and increased in total water storage by 110.15 ± 7.93 km3 from 1990 to 2013. The water storage increase in glacier-fed lakes was 84% of the total increase in water storage from 1990 to 2013. An analysis of the relationship between the lakes and climate indicators suggests that both precipitation and glacial meltwater were the most important factors in lake change, in contrast, changes in evaporation had a limited influence on lake level and volume changes. Based on an assumption of similar precipitation and evaporation across neighbouring closed basins, we compared differences in LWSC between glacier-fed and non-glacier-fed lakes to analyze the cause of lake change. Our results suggest that less precipitation was the primary cause for lake contractions from 1976 to 1990. Glacial meltwater contributed at least 43.5%, 46.4% and 58.7% to the total increased water storage for the periods 1990-2000, 2000-2005 and 2005-2013, respectively. The results further suggest that increasing glacial meltwater had a contribution to lake expansion equivalent to that of precipitation-evaporation during 1990-2013.