Mapping of Ice Motion in Antarctica Using Synthetic-Aperture Radar Data

• Published in: Remote Sensing
• Main Authors: Bernd Scheuchl, Eric Rignot, Jeremie Mouginot
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2012
• Subjects: Antarctica; InSAR; ice motion; Science; Q; Antarctic; The Antarctic; Asar; Antarc*
• Online Access: https://doi.org/10.3390/rs4092753; https://doaj.org/article/1b19c4f136ab4a86bdd1b76a530a502c

Ice velocity is a fundamental parameter in studying the dynamics of ice sheets. Until recently, no complete mapping of Antarctic ice motion had been available due to calibration uncertainties and lack of basic data. Here, we present a method for calibrating and mosaicking an ensemble of InSAR satellite measurements of ice motion from six sensors: the Japanese ALOS PALSAR, the European Envisat ASAR, ERS-1 and ERS-2, and the Canadian RADARSAT-1 and RADARSAT-2. Ice motion calibration is made difficult by the sparsity of in-situ reference points and the shear size of the study area. A sensor-dependent data stacking scheme is applied to reduce measurement uncertainties. The resulting ice velocity mosaic has errors in magnitude ranging from 1 m/yr in the interior regions to 17 m/yr in coastal sectors and errors in flow direction ranging from less than 0.5 in areas of fast flow to unconstrained direction in sectors of slow motion. It is important to understand how these mosaics are calibrated to understand the inner characteristics of the velocity products as well as to plan future InSAR acquisitions in the Antarctic. As an example, we show that in broad sectors devoid of ice-motion control, it is critical to operate ice motion mapping on a large scale to avoid pitfalls of calibration uncertainties that would make it difficult to obtain quality products and especially construct reliable time series of ice motion needed to detect temporal changes.