Freeboard and mass extraction of the disintegrated Mertz Ice Tongue with remote sensing and altimetry data

Abstract

In February 2010, the Mertz Ice Tongue (MIT) collapsed and generated a giant iceberg. However, parameters about this iceberg have not been calculated and published in detail. In this study, the freeboard map of this iceberg was generated for the first time using a time-series ICESat/GLAS data. Methods for producing the freeboard map of this iceberg are suggested. Field data for ice velocity were used to relocate the footprints collected by different campaigns. Cross-validation was conducted with freeboards extracted from crossovers observed within 30days of each other. The precision of the freeboard extraction is approximately ±0.50m, when taking one standard deviation as the precision. The freeboard varied from 23m to 59m with the mean of 41m. With assumption of hydrostatic equilibrium (assuming a snow layer depth of 1m, a snow density of 360kg/m3, an ice density of 915kg/m3 and a sea water density of 1024kg/m3), the minimum, maximum and average ice thickness were calculated as 210m, 550m and 383m respectively. The total ice loss is approximately 8.96×1011tons over an area, 34km in width and 75km in length, or approximately 2560±5km2. These parameters extracted from remote sensing and altimetry data will provide additional information for studies of the evolution of iceberg, especially in iceberg tracking system.