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Abstract: In recent years, disasters caused by Glacial Lake Outburst Floods (GLOFs) have taken place more frequently in Tibet than previously and have been the cause of considerable losses. Temperature fluctuations are believed a major influencing factor of GLOFs. However, if or how much climatic change influences GLOFs is a question that remains to be answered. In this paper, using 24 GLOFs related to 19 glacial lakes and temperature data from 14 meteorological stations, we explored the relationships between temperature variations on different temporal scales (annual, monthly, and daily) and GLOFs. There were three active periods for GLOFs in the 1960s, 1980s and 2000s in Tibet, when 16 of 24 GLOFs took place. All the studied GLOFs occurred in the ablation months (from May and September, and especially in July and August) and on ablation days with a monthly average temperature and daily average temperature that were both greater than 0 °C. Based on the analysis of monthly and daily temperature, GLOFs depend on the coupled influence of ablation temperature and accumulation temperature; even the accumulation temperature may be important. Based on this, temperature increments were defined, representing the change from accumulation to ablation temperature with a significant impact on GLOFs. There is an altitude effect on GLOFs, in that lakes at lower altitude generally burst earlier, whereas those at a higher altitude burst later. The monthly and daily increments increase according to a similar power-law form with elevation. [Copyright &y& Elsevier]

This paper describes 2007/2008 inter-annual changes in runoff from the Zhadang Glacier located on the northern slope of Nyainqêntanglha Range, Tibet, and analyzes their causes. Precipitation increased by 17.9% in summer months of 2008 compared with the same period in 2007, drainage basin runoff decreased by 33.3%, and glacial meltwater decreased by 53.8%. Change in positive accumulated air temperature explained approximately half of the inter-annual difference in glacial meltwater using a degree-day model. This suggests that the glacier is extremely sensitive to changes in air temperature. Energy balance analysis showed that change in glacier surface albedo, considered to be caused by difference in precipitation form, resulted in the large inter-annual difference in glacial meltwater. It was shown statistically that precipitation form in the summer months of 2007 was mainly rainfall which comprised 71.5% of total precipitation, while during the same period in 2008 rainfall accounted for 30.7%, with the majority of precipitation falling as snow. Precipitation form should be considered an independent factor when analyzing glacier sensitivity to climate change or forecasting the runoff from certain glaciers. [ABSTRACT FROM AUTHOR]