关键词: 可可西里, 岗扎日, 冰川变化, 物质平衡, 遥感

Abstract:

Hoh Xil is located in the central Tibetan Plateau, and is the transitional zone of the natural environment of the Tibetan Plateau. In recent years, the mass balance of the glaciers in this region has a trend of positive turning to negative from west to east. However, mass change of glaciers in KangzhagRi, as the transition zone of Hoh Xil region, is unknown due to its inaccessibility and high labour costs. Glacier mass changes in KangzhaRi were determined using geodetic methods based on digital elevation models (DEMs) derived from the topographic map (1970), ASTER (2012) and Shuttle Radar Terrain Mission (SRTM) data (2000). Glacier area changes between 1970 and 2016 were derived from the topographic map, ASTER, and Landsat data. Results show that KangzhaRi has 50 glaciers with an area of 162.6±1.3 km² in 2016. Average glacier area change was observed to be -0.08±0.02% a^-1 from 1970 to 2016. Weak area shrinkage of glaciers by 0.04±0.30% a^-1 during 2006-2012 and 0.01±0.38% a^-1 during 2012-2016. The glaciers in this region have experienced an overall loss of 1.45±0.06 km³ in ice volume or -0.21±0.01 m water equivalent (w.e.) a^-1 from 1970 to 2012. The glaciers lost mass at a rate of -0.34 ± 0.01 m w.e.a^-1 during 1970-1999, while gained mass at a rate of 0.16±0.02 m w.e.a^-1 during 1999-2012. Glaciers with southeastern, southern, southwestern aspect showed a slight mass loss during 1970-2012, while gained most mass during 1999-2012. However, Glaciers with southeastern and eastern aspect showed more stable in the ice cover area. Because these glaciers have a long tongue with low terminal altitudes with a little mass supply from accumulation region. Air temperature rises contribute to the loss of glacier mass during 1970-1999, while precipitation increase contributes to the gain of glacier mass during 1999-2012. Glacier area reduction from 1970s shows a trend of low to high from the west to east, and the mass balance gradually decreases from the west to east. Glacier variations in KangzhagRi were not only related to westerly circulation and monsoon circulation, but also related to local circulation. Recent mass change might be a response to the changing atmospheric circulation pattern.

Key words: Hoh Xil, KangzhagRi, glacier change, mass change, remote sensing