Monthly velocity estimation of mountain glaciers based on Sentinel-1A data

The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research. In this study, 10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier No.1 in 2017 were used to calculate the glacier flow velocity in a high coherence period by DInSAR technology and MAI technology, while the offset tracking technology was used to estimate the glacier flow velocity in a low coherence period. Then, the monthly three-dimensional flow velocity of the glacier was calculated by the Helmert variance component estimation method. Finally, the accuracy of the estimated glacier flow velocity on a monthly scale was evaluated. The results showed that: (1) the monthly scale motion velocity of Urumqi Glacier No.1 in May, June, July, and August 2017 was 0.273 m/month, 0.657 m/month, 0.582 m/month, and 0.392 m/month, respectively. (2) The accuracy of glacier surface velocity from May 2017 to August 2017 was 0.033 m/month, 0.026 m/month, 0.034 m/month and 0.037 m/month, respectively. (3) The accuracy of glacier surface flow velocity from May 2017 to August 2017 was 0.018 m/month, 0.031 m/month, 0.029 m/month and 0.030 m/month, respectively. Therefore, the research methodology based on the Sentinel-1 ascending and descending data and presented in this paper was applicable to the estimation of monthly-scale flow velocity of mountain glaciers.