Growth of a high-elevation large inland lake, associated with climate change and permafrost degradation in Tibet
- 1Nam Co Monitoring and Research Station for Multisphere Interaction, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
- 2Hydrology and Water Resources Bureau of Tibet, Lhasa 850000, China
- 3Key Laboratory of Cryosphere and Environment, Cold and Arid Regions Environmental and Engineering Institute, Chinese Academy of Sciences, Lanzhou 730000, China
Abstract. This study analyzed satellite images and long term climate variables from a high-elevation meteorological station (4730 m) and streamflow records to examine hydrological response of Nam Co Lake (4718 m), the largest lake on the Tibetan Plateau, over the last 50 years. The results show the lake area extended by 51.8 km2 (2.7% of the total area) when compared with the area in 1976. This change is associated with an annual precipitation increase of 65 mm (18.6%), annual and winter mean temperature increases of 0.9 °C and 2.1 °C respectively, an annual runoff increase of 20% and an annual pan evaporation decrease of about 2%, during the past 20 years. The year of the change point in annual precipitation, air temperature, annual pan evaporation and runoff occurred in 1971, 1983, 1997 and 1997, respectively. The timing of the lake growth corresponds with the abrupt increase in annual precipitation and runoff since the mid-1990s.