Evaluating the Impact of Radiometric Calibration and Thermal Noise Removal on Glacier Velocity Estimates from Sentinel-1 SAR Data: A Case Study on Livingston Island

Abstract

This study evaluates whether applying pre-processing to Sentinel-1 GRD (Ground Range Detected) SAR images alters the accuracy of glacier surface velocity estimates obtained with an offset-tracking algorithm. The pre-processing includes applying thermal noise removal and radiometric calibration deriving sigma0 type products. The research focuses on glaciers near the Bulgarian research base on Livingston Island (Antarctica), using available in-situ GNSS velocity measurements as ground truth. Three nearly identical processing chains were implemented in ESA's SNAP software: one including radiometric calibration (producing sigma0) and thermal noise removal, one with only thermal noise removal, and one with neither. All other processing steps and parameters were held constant to isolate the effect of calibration and thermal noise removal.