Lake change and its implication in the vicinity of Mt. Qomolangma (Everest), central high Himalayas, 1970-2009

摘要

High-elevation inland lakes are a sensitive indicator of climate change. The extents of lakes in Mt. Qomolangma region have been extracted using the object-based image-processing method providing 6-24 images during 1970-2009. Combined with data from five meteorological stations and three periods' glacier data, the inter-annual and intra-annual lake changes and responses to climate and glacier change have been analyzed. The results show that the lakes have shrunk overall, with clear inter-annual and intra-annual fluctuations during 1970-2009. In general, there appeared a trend of slight shrinkage in the 1970s, distinct shrinkage around 1990, general expansion in 2000 and accelerated decrease after 2000. Lake Peiku and neighboring lakes show a highly consistent change trend (correlation coefficients of 0.68-0.91), with larger lakes having smaller shrinkage rates, which implies a higher stability (in the order of Peiku > Langqiang > Cuochuolong). Lake Peiku, the largest lake, decreased 10.38 km~2 (3.69 or 0.27 km~2 year~(-1)) during 1970-2009. The changes in Lake Peiku indicate that precipitation is its main source of supply with glacier melt water a key supplement. Meanwhile, Lake Como Chamling reduced by 13.12 km~2 (19.79 ) during 1974-2007, with strong shrinkage-expansion-shrinkage-expansion fluctuations. Overall, lakes in the vicinity of Mt. Qomolangma are a sensitive good indicator to climate change.