Spatial-Temporal Characteristics of a Temperate-Glacier's Active-Layer Temperature and Its Responses to Climate Change: A Case Study of Baishui Glacier No. 1, Southeastern Tibetan Plateau

Based on the historical documents and measured data from the active-layer temperature （ALT） at A, B and C locations （4 670, 4 720 and 4 770 m a.s.l.） on Baishui Glacier No. 1, southeastern Tibetan Plateau, this paper analyzed spatial-temporal characteristics of ALT and its relationship with air temperature, and revealed the response of the active layer ice temperature towards climate change in the monitoring period. The results showed that the influence of air temperature on the active-layer ice temperature had a hysteresis characteristic on the upper of ablation zone and the lag period in- creased gradually with the altitude elevating. The decrease amplitude of ALT in the accumulation pe- riod was far below its increase magnitude in the ablation period. At the same time, the mean glacier ice temperatures at 10 m depth （T10） in A, B and C profile were obviously higher than most of glaciers previously studied. Measured data also showed that the mean ALT increased by 0.24℃ in 0.5-8.5 m depth of the C profile during 28 years from July 11, 1982 to July 10, 2009.

Comparisons of stable isotopic fractionation in winter and summer at Baishui Glacier No.1,Mt.Yulong,China

Based on the data of δ^18O in surface snow, snow pits, meltwater and the glacier-fed fiver water at Baishui Glacier No. 1, Mt. Yulong, the isotopic fractionation behaviors in the typical monsoonal temperate glacier system in winter and summer were compared. The results indicate that the isotopic fractionation degree in summer is greater than that in winter, suggesting that the snow/ice melting is more intense in summer. Moreover, whenever it is in winter or summer, from surface snow to meltwater, and to glacier-fed fiver water, the gradient of δ^18O with altitude gradually increases. This shows that the degree of isotopic fractionation gradually strengthens when surface snow is being converted into meltwater and finally into glacial fiver water, which suggests that the influence of post-depositional processes on δ^18O gradient in the monsoonal temperate glacier region differs spatially.

Contemporary processes of environmental information in the atmosphere-glacier-runoff system in an area of typical monsoon temperate glacier

Sampling was carried out at Baishui No.1, the largest glacier on Mt. Yulong, China, during the summers of 1999 and 2000, to investigate the spatial variations of oxygen isotopes in the atmosphere-glacier-river system. The results confirm that there is an inverse relation between the oxygen isotopic composition of precipitation and air temperature/precipitation amount. This suggests that a strong 'precipitation amount effect' exists in this typical monsoon temperate-glacier region. There are marked differences of the δ18O values of winter-accumulated snow, glacial meltwater, summer precipitation and the glacier-fed river water. Spatial and temporal variations of isotopic composition are controlled by climatic conditions. Isotopic fractionation and differentiation occur during phase changes, snow-to-ice and ice-to-meltwater transformations, and runoff processes. Variations of stable isotopes in glacier runoff can indicate variations of sources of supply, as well as different discharge-related processes. Ionic changes occur as a result of meltwater contact with glacier bed materials.