Observed Glaciohydrological Changes in China's Typical Monsoonal Temperate Glacier Region since 1980s

Under the background of significant climate warming since the 1980s, the glaciers in China＇s monsoonal temperate glacier region respond to the warming intensely. Based on the glaciohydrological observations at some typical glaciers from Mts. Yulong （玉龙） and Gongga （贡嘎） of Hengduan （横断） Mountains Range in the southeastern Tibetan plateau, the glaciohydrological changes in the temperate glacier region since the 1980s were investigated. First, the glacier terminus exhibited an accelerating retreat. Second, as the glacier area subject to melting has increased and the ablation season has become longer due to the warming, the ablation of glacier enhanced, leading to increasing contribution of meltwater to annual river discharge. Third, surface topography of small temperate glacier may be changed significantly by crevasses and ruptures developed in the accumulation zone and ice collapse events in the ablation zone. The observed results may indicate a signal that the survival of glaciers in China＇s monsoonal temperate glacier region is being threatened by today＇s climate warming.

Distribution features of stable oxygen isotopes in the typical monsoon temperate-glacier region, Mountain Yulong in China

During the summers of 1999 and 2000, sampling was carried out in Mt. Yulong, for the investigation of the spatial distribution of oxygen stable isotope in the atmospheric glacial hydro system and similar results obtained in the two years have confirmed our conclusion. There is an evident negative correlation between stable isotopic composition and air temperature precipitation amount, suggesting that there exits a strong 'precipitation amount effect' in this typical monsoon temperate glacier region. There are marked differences between the δ 18 O values in winter accumulated snow, glacial meltwater, summer precipitation and glacier feeding stream. Under the control of varied climatic conditions, spatial and temporal variations of above glacial hydro mediums are apparent. Isotopic depletion or fractionation and ionic changes had occurred during the phase change and transformation processes of snow ice, ice meltwater, flowing of runoff and contact with bedrock. The variation of stable isotope in a runoff can reflect not only its own flowing process but also its different feeding sources.

Dynamics of the spatiotemporal velocity of glaciers on the eastern slope of Mount Gongga,China,under climate change

The quantitative assessment of glacier flow velocity dynamics plays a pivotal role in understanding its response mechanisms concerning climate warming.This work provides a systematic quantitative assessment of the deceleration status of glaciers in this region by investigating the motion evolution of typical glaciers in Mount Gongga in recent years,thereby revealing the seasonal dynamics and inter-annual evolution over an extensive time span.We used the optical flow-small baseline subset(OF-SBAS)method to compute the time-series velocities of the Hai-luogou Glacier and the Mozigou Glacier using 178 archived Sentinel-1 satellite synthetic aperture radar(SAR)images from 2014 to 2021.The findings revealed a prominent seasonal pattern in glacier motion,characterised by cyclic variations in velocity from cold to warm seasons.Moreover,we identified variations in velocities across distinct regions of the glacier surface,underscored by the lag in the peak time node of glacier flow with increasing elevation.This pattern may have been determined by a combination of internal and external factors,including mass accumulation and ablation-driven subglacial drainage,as well as the glacier geomorphological setting.Furthermore,during 2015-2021,the glaciers on the eastern slope of Mount Gongga exhibited an overarching trend of deceleration.Notably,the ablation area of the Hailuogou Glacier recorded the most substantial deceleration,exceeding 8%per year.This study underscores the efficacy of the OF-SBAS method in extracting long-term glacier velocities.This work also establishes a robust foundation for the analysis of spatiotemporal fluctuations in glacier movement within the context of climate warming.

Characteristics of DDF at Baishui Glacier No.1 Region in Yulong Snow Mountain

Based on observed mass balance and meteorological data since September 2008 and ablation data by the expedition team of Tibetan plateau from June to August 1982 at Baishui （白水） Glacier No. 1 region, we analyzed the spatial and temporal changes of degree-day factor （DDF） of the Baishui Glacier No. 1 following the changes of space, time, and temperature, which lays a theoretical foundation to establish DDF model. The results indicate that the melting DDF of ice showed a significant downward trend with rising temperatures, and larger value of DDF only appeared at low temperature conditions. A larger value of DDF appeared in the high altitude areas, and as altitude rises, the value of DDF increased. The snow DDF is lower than the DDF of ice, and the DDF is higher in temperate glaciers than those in other glaciers. The melting DDF of snow has a more obvious seasonal variation than the melting DDF of ice.