CryoSat swath altimetry to measure ice cap and glacier surface elevation change
Abstract
Satellite altimetry has been used extensively in the past few decades to observe changes affecting large and remote regions covered by land ice such as the Greenland and Antarctic ice sheets. Glaciers and ice caps have been studied less extensively due to limitation of altimetry over complex topography. However their role in current sea-level budgets is significant and is expected to continue over the next century and beyond (Gardner et al., 2011), particularly in the Arctic where mean annual surface temperatures have recently been increasing twice as fast as the global average (Screen and Simmonds, 2010). Radar altimetry is well suited to monitor elevation changes over land ice due to its all-weather year-round capability of observing ice surfaces. Since 2010, the Synthetic Interferometric Radar Altimeter (SIRAL) on board the European Space Agency (ESA) radar altimetry CryoSat (CS) mission has been collecting ice elevation measurements over glaciers and ice caps. Its Synthetic Aperture Radar Interferometric (SARIn) processing feature reduces the size of the footprint along-track and locates the across-track origin of a surface reflector in the presence of a slope. This offers new perspectives for the measurement of regions marked by complex topography. More recently, data from the CS-SARIn mode have been used to infer elevation beyond the point of closest approach (POCA) with a novel approach known as "swath processing" (Hawley et al., 2009; Gray et al., 2013; Christie et al., 2016; Smith et al., 2016). Together with a denser ground track interspacing of the CS mission, the swath processing technique provides unprecedented spatial coverage and resolution for space borne altimetry, enabling the study of key processes that underlie current changes of ice caps and glaciers. In this study, we use CS swath observations to generate maps of ice elevation change for selected ice caps and glaciers. We present a validation exercise and discuss the benefit of swath processing for assessing glaciers and ice caps changes and their contribution to changes in sea level.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.C11E..04T
- Keywords:
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- 0720 Glaciers;
- CRYOSPHEREDE: 0758 Remote sensing;
- CRYOSPHERE