Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 11, 997-1014, 2017
http://www.the-cryosphere.net/11/997/2017/
doi:10.5194/tc-11-997-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
20 Apr 2017
Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry
Xiaowen Wang1,2, Lin Liu1, Lin Zhao3, Tonghua Wu3, Zhongqin Li3, and Guoxiang Liu2 1Earth System Science Programme, Faculty of Science, Chinese University of Hong Kong, Hong Kong, China
2Department of Surveying and Geo-Informatics, Southwest Jiaotong University, Chengdu, China
3Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
Abstract. Rock glaciers are widespread in the Tien Shan. However, rock glaciers in the Chinese part of the Tien Shan have not been systematically investigated for more than 2 decades. In this study, we propose a new method that combines SAR interferometry and optical images from Google Earth to map active rock glaciers (ARGs) in the northern Tien Shan (NTS) of China. We compiled an inventory that includes 261 ARGs and quantitative information about their locations, geomorphic parameters, and downslope velocities. Our inventory shows that most of the ARGs are moraine-derived (69 %) and facing northeast (56 %). The altitude distribution of ARGs in the western NTS is significantly different from those located in the eastern part. The downslope velocities of the ARGs vary significantly in space, with a maximum of about 114 cm yr−1 and a mean of about 37 cm yr−1. Using the ARG locations as a proxy for the extent of alpine permafrost, our inventory suggests that the lowest altitudinal limit for the presence of permafrost in the NTS is about 2500–2800 m, a range determined by the lowest ARG in the entire inventory and by a statistics-based estimation. The successful application of the proposed method would facilitate effective and robust efforts to map rock glaciers over mountain ranges globally. This study provides an important dataset to improve mapping and modeling permafrost occurrence in vast western China.

Citation: Wang, X., Liu, L., Zhao, L., Wu, T., Li, Z., and Liu, G.: Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry, The Cryosphere, 11, 997-1014, doi:10.5194/tc-11-997-2017, 2017.
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Short summary
Rock glaciers are abundant in high mountains in western China but have been ignored for 20 years. We used a new remote-sensing-based method to map active rock glaciers in the Chinese part of the Tien Shan and compiled an inventory of 261 active rock glaciers and included quantitative information about their locations, geomorphic parameters, and downslope velocities. Our dataset suggests that the lower limit of permafrost there is 2500–2800 m.
Rock glaciers are abundant in high mountains in western China but have been ignored for 20...
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