Recent geodetic mass balance and extent changes of very small glaciers in the Hulugou Basin, Central Qilian Mountains, China

Abstract

Very small glaciers (<0.5km2) account for more than 70% of the total number of glaciers in the Qilian Mountains. Despite their total area and volume being small, they are important water resources in the Hexi Corridor. While glacier monitoring mostly focuses on medium-sized and large valley glaciers (e.g., Qiyi Glacier and Laohugou Glacier No. 12) in the Qilian Mountains, little is known about very small glacier mass balance in this region. This study presents a geodetic mass balance of six very small glaciers in the Hulugou Basin by comparing Shuttle Radar Topography Mission (SRTM) C-band (2000) and airborne laser scanning (2012) digital elevation models (DEMs). The total glaciers’ area decreased by 23.6% at a rate of 0.024km2a - 1 and the geodetic mass balance was -0.68±0.11m water equivalent (m w.e.) a - 1 from 2000 to 2012. Shiyi Glacier, as the monitored glacier in the Basin, had lost 10.9% of the surface area at a rate of 0.005km2a - 1 and the geodetic mass balance was -0.53±0.11m w.e. a - 1 for the period. Climatic variations over the last decade showed a pronounced increase in summer temperatures. The warmer conditions probably explain the glaciers mass loss observed in the Hulugou Basin.