Acta Geographica Sinica ›› 2017, Vol. 72 ›› Issue (9): 1606-1620.doi: 10.11821/dlxb201709006

• Orginal Article • Previous Articles     Next Articles

Research progress on debris thickness estimation and its effect on debris-covered glaciers in western China

Yong ZHANG1(), Shiyin LIU2,3,4   

  1. 1. School of Resource Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411021, Hunan, China
    2. Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650091, China
    3. Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Kunming 650091, China
    4. State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China
  • Received:2016-12-27 Revised:2017-05-02 Online:2017-09-30 Published:2017-09-30

Abstract:

Debris-covered glaciers, characterized by the presence of supraglacial debris mantles in their ablation zones, are widespread in high mountain regions of western China. Supraglacial debris cover on glaciers has the unique thermal process relative to exposed snow and ice, the spatial distribution of which influences both rates and spatial patterns of melting. Due to the debris-cover effect, the responses of debris-covered glaciers to climate change are more complex compared to those of debris-free glaciers. In addition, debris-covered glaciers generally contain a large ice volume, and mass changes of these glaciers are expected to have significant impacts on the regional-scale evolution of river discharge and water resources. However, a better understanding of debris-cover effect in glacier status and hydrology at a regional scale remains a challenge. The difficulty of such a study arises mainly from limited knowledge of the large-scale spatial distribution of the thickness and properties of the debris cover in western China. This study systematically reviews the impacts of the spatial distribution of debris thickness on melting beneath surface debris, mass change and runoff process on debris-covered glaciers. In particular, a physically-based assessment model for debris-cover effect is proposed, which is based on visible and near infrared and thermal infrared bands of remotely sensed data and surface energy-balance process of the debris layer. This model does not require high-quality input parameters related to the extent, thickness and thermal properties of the debris cover, and has been applied to different glaciers of western China for systematically assessing the significance of debris cover and its influence on spatial patterns of ice melting, mass balance and runoff. This approach provides an important insight into exploring the average status of debris-covered glaciers and its impacts on regional water resources in western China. Nevertheless, this approach does not consider the effect of the complex surface composed of co-existing debris-covered ice, bare ice, ice cliffs and supraglacial ponds in the ablation zone, and needs further improvement in the future.

Key words: debris-covered glacier, debris cover, thermal resistance, melting, water resources, China