Glacier Image Velocimetry: an open-source toolbox for easy and rapid calculation of high-resolution glacier velocity fields

Abstract

Abstract. We present Glacier Image Velocimetry (GIV), an open-source and easy-to-use software toolkit for rapidly calculating high-spatial-resolution\nglacier velocity fields. Glacier ice velocity fields reveal flow dynamics, ice-flux changes, and (with additional data and modelling) ice\nthickness. Obtaining glacier velocity measurements over wide areas with field techniques is labour intensive and often associated with safety\nrisks. The recent increased availability of high-resolution, short-repeat-time optical imagery allows us to obtain ice displacement fields using\n“feature tracking” based on matching persistent irregularities on the ice surface between images and hence, surface velocity over time. GIV is\nfully parallelized and automatically detects, filters, and extracts velocities from large datasets of images. Through this coupled toolchain and an\neasy-to-use GUI, GIV can rapidly analyse hundreds to thousands of image pairs on a laptop or desktop computer. We present four example applications\nof the GIV toolkit in which we complement a glaciology field campaign (Glaciar Perito Moreno, Argentina) and calculate the velocity fields of small\nmid-latitude (Glacier d Argentiere, France) and tropical glaciers (Volcan Chimborazo, Ecuador), as well as very large glaciers (Vavilov Ice Cap,\nRussia). Fully commented MATLAB code and a stand-alone app for GIV are available from GitHub and Zenodo (see https://doi.org/10.5281/zenodo.4624831 , Van Wyk\xa0de Vries ,\xa0 2021 a ).