sakai_etal_2001.html

Bulletin of Glaciological Research 18 (2001) 37-44
©Japanese Society of Snow and Ice

Thermal regime of a moraine-dammed glacial lake, Tsho Rolpa, in Rolwaling Himal, Nepal Himalayas

Akiko SAKAI¹, Tomomi YAMADA² and Kazuhisa CHIKITA³
1 Institute for Hydrospheric-Atmospheric Sciences, Nagoya University, Nagoya 464-8601 Japan
2 Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 Japan
3 Division of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 Japan

Abstract

In the Nepal Himalayas there are many glacial lakes of the 1 km order scale on the surface of debris-covered glaciers. Tsho Rolpa Glacial Lake in eastern Nepal was once a small pond probably in the early 1950s, and now has become the largest glacial lake in the Nepal Himalayas. It is significant to clarify the heat source for the expansion process of a glacial lake. However, the present thermal regime of the glacial lake is still unknown. Hence, the heat balance of the lake was examined from the meteorological and hydrological data in 1993 to 1996. The result shows the increasing heat storage period of the lake was concentrated in May i.e., between the end of the ice-covered period and the start of the glacier melt season. During the monsoon season the heat loss by discharge was large, and the heat storage of the lake continue to decrease until October. During the ice-covered period from November to end of April, there are no heat input to the lake surface and no heat loss with discharge. On the other hand, the bottom ice continues to melt through a year by the heat storage in the lake.