Dynamics of Stage Fluctuation in Yangzhouyongcuo Lake, Tibetan Plateau

Abstract

Yangzhourongcuo Lake is the largest closed interior lake in the southern part of the Qingzang (Tibetan) Plateau, with a drainage area of 6100 km². The elevation of the lake stage is 4440 m and lake storage is about 16 billion m³. Water recharge mainly depends on rainfall, with meltwater from glaciers accounting for up to 16%. About 2% of the drainage basin is covered by glaciers. The seasonal range of variation in the lake stage is small, usually less than 0.6 m. Highest water level occurs in September or October, not in July or August, the main rainfall period, because of the lake’s self-adjustment. Lowest lake level occurs in May, June or July. In wet years the stage fluctuation has clear periodicity; in dry years the lake level tends to remain low throughout the year. Analysis of the patterns of lake level fluctuation during the last 100 years shows that the lake levels have varied by up to 4–5 m, and have been gently descending at a rate of 0.6 m per 100 years.