Continent-wide estimates of Antarctic strain rates from Landsat 8-derived velocity grids

• Published in: Journal of Glaciology
• Main Authors: KAREN E. ALLEY, TED A. SCAMBOS, ROBERT S. ANDERSON, HARIHAR RAJARAM, ALLEN POPE, TERRY M. HARAN
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2018
• Subjects: Antarctic glaciology; glacier flow; ice dynamics; ice velocity; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Antarctic; The Antarctic; Antarc*; Ice Sheet; Ice Shelves; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2018.23; https://doaj.org/article/3be17fe1c10f4174a2f7cfbd3b526d5d

Strain rates are fundamental measures of ice flow and are used in a wide variety of glaciological applications including investigations of bed properties, calculations of basal mass balance on ice shelves, and constraints on ice rheological models. However, despite their extensive application, strain rates are calculated using a variety of methods and length scales and the details are often not specified. In this study, we compare the results of nominal and logarithmic strain-rate calculations based on a satellite-derived velocity field of the Antarctic ice sheet generated from Landsat 8 satellite data. Our comparison highlights the differences between the two common approaches in the glaciological literature. We evaluate the errors introduced by each approach and their impacts on the results. We also demonstrate the importance of choosing and specifying a length scale over which strain-rate calculations are made, which can strongly influence other derived quantities such as basal mass balance on ice shelves. Finally, we present strain-rate data products calculated using an approximate viscous length-scale with satellite observations of ice velocity for the Antarctic continent.