Extreme lake expansion on the Tibetan Plateau: Observations and consequences

After the considerable lake level decrease in 2015 in response to the super 2015/2016 El Niño and lake level recovery in 2016, an extreme lake expansion occurred on the central and northern TP in the following two years (2017 and 2018), in contrast with the slight lake level changes on the southern TP. In-situ observations at Zhari Namco near Cuoqing County show that lake level increased abruptly by 1.4 m and 1.7 m in summer 2017 and 2018, respectively, which was even close to the accumulated lake level increase between 2000 and 2015. At Dazeg Co near Nima Country, lake level increased by 0.9 m and 1.4 m in summer 2017 and 2018, respectively, which is about 3 times as large as the increasing rate between 2000 and 2015. At Eya Co and Cedo Caka near Shuanghu County, lake level accumulatively increased by 1.5 m and 2.0 m, respectively, in the two years. The extreme lake expansion had significant impact on geomorphology and even posed great threat on the infrastructures such as road and bridges around the lakes. Causes of the extreme lake expansion are investigated by examining precipitation data and changes in large scale circulations.