Paper Info
Title
Sub-Annual Calving Front Migration, Area Change and Calving Rates from Swath Mode CryoSat-2 Altimetry, on Filchner-Ronne Ice Shelf, Antarctica
Abstract
Mapping the time-variable calving front location (CFL) of Antarctic ice shelves is important for estimating the freshwater budget, as an indicator of changing ocean and structural conditions or as a precursor of dynamic instability. Here, we present a novel approach for deriving regular and consistent CFLs based on CryoSat-2 swath altimetry. The CFL detection is based on the premise that the shelf edge is usually characterized by a steep ice cliff, which is clearly resolved in the surface elevation data. Our method applies edge detection and vectorization of the sharp ice edge in gridded elevation data to generate vector shapefiles of the calving front. To show the feasibility of our approach, we derived a unique data set of ice-front positions for the Filchner-Ronne Ice Shelf (FRIS) between 2011 and 2018 at a 200 m spatial resolution and biannual temporal frequency. The observed CFLs compare well with independently derived ice front positions from Sentinel-1 Synthetic Aperture Radar imagery and are used to calculate area change, advance rates, and iceberg calving rates. We measure an area increase of 810 +/- 40 km(2) a(-1) for FRIS and calving rates of 9 +/- 1 Gt a(-1) and 7 +/- 1 Gt a(-1) for the Filchner and Ronne Ice Shelves, respectively, which is an order of magnitude smaller than their steady-state calving flux. Our findings demonstrate that the "elevation-edge" method is complementary to standard CFL detection techniques. Although at a reduced spatial resolution and less suitable for smaller glaciers in steep terrain, it enables to provide CFLs at regular intervals and to fill existing gaps in time and space. Moreover, the method simultaneously provides ice thickness, required for mass budget calculation, and has a degree of automation which removes the need for heavy manual intervention. In the future, altimetry data has the potential to deliver a systematic and continuous record of change in ice shelf calving front positions around Antarctica. This will greatly benefit the investigation of environmental forcing on ice flow and terminus dynamics by providing a valuable climate data record and improving our knowledge of the constraints for calving models and ice shelf freshwater budget.
Year
DOI
Venue
2019
10.3390/rs11232761
REMOTE SENSING
Keywords
DocType
Volume
Earth Observation,altimetry,calving front location (CFL),edge detection,CryoSat-2,swath processing,Antarctica,Filchner-Ronne Ice Shelf,iceberg calving
Journal
11
Issue
Citations 
PageRank 
23
0
0.34
References 
Authors
0
6
Name
Order
Citations
PageRank
jan wuite1122.27
Thomas Nagler25714.13
Gourmelen, N.302.37
Maria José Escorihuela49514.60
Anna E. Hogg500.68
Mark R. Drinkwater626721.93