Determining the spatio-temporal variability of glacier surface velocity using high-resolution satellite images and UAV data: Alamkuh glacier, Iran

Abstract

ABSTRACT In this study, multi-temporal high-resolution satellite and Unmanned Aerial Vehicle (UAV) images were obtained to determine glacier kinematics and dynamics for the first time in Iran, which could enhance our understanding of debris-covered glacier change mechanisms in this part of the world. the flow velocity change of Alamkouh debris-covered glacier in Iran was surveyed using the combination of very high-resolution satellite and UAV imageries from 2005 to 2020. Glacier surface velocity (GSV) during the last 15 years was analysed by employing the frequency cross-correlation technique using Co-registration of Optically Sensed Images and Correlation (COSI-Corr) module on Quickbird (2005), Wordview-2 (2010) and UAV images (2018 and 2020) for the periods 2005–2010, 2010–2018 and 2018–2020, respectively. Results indicate that the mean annual GSV does not remain constant and fluctuates in different periods without a clear and straightforward increasing or decreasing trend. The mean annual GSV in the whole part of the glacier area from 2005 to 2010 was about 1.06 m year−1. Then, it decreases to 0.69 m year−1 during 2010–2018 and finally, it increases to 1.08 m year−1 during 2018–2020. Spatially, monitoring glacier velocity change during the last fifteen years indicates that glacier activity decreased at the lowest part of the glacier and the velocity had increased with a rising altitude from the glacial tongue to the high elevation accumulation areas.