Development of improved Google Earth Engine (GEE) Glacier velocity
estimation algorithms for long-term & large-scale monitoring of glacier
velocities
Abstract
Feature tracking is an efficient method for estimating glacier velocity
by identifying the surface displacement between image pairs through
maximum normalized cross-correlation (NCC). However, this method may
misidentify displacement when noise is present in one or both images or
when natural causes change glacier morphology. To improve accuracy, we
developed the Google Earth Engine Glacier Velocity (GEEG-Vel) estimation
method, which utilizes image enhancement and multi-image pair NCC
maximization. GEEG-Vel results are further filtered using PyFilter, a
Python routine that improves the glacier velocity estimation by
utilizing velocity pairs obtained from GEEG-Vel. The combination of
GEEG-Vel and PyFilter provides an efficient and accurate approach for
glacier velocity estimation across various types of datasets, including
optical and SAR data. We compared the results with the ITS_LIVE glacier
velocity for the same period (2013-2018), and the mean velocity
difference for each year was less than 10 m/year. Our study demonstrates
that the combination of GEEG-Vel and PyFilter provides a reliable and
accurate approach for glacier velocity estimation, which can be useful
for monitoring the dynamics of glaciers and their response to climate
change.