Unravelling East Antarctic sea-ice and snow thickness from ICESat-2 using in situ and OIB measurements

Abstract:

After three decades of minor increase, the recent satellite records provides clear evidence of dramatic reduction of the annual maximum Antarctic sea-ice extent. However, little is known about concomitant changes in the ice structure including ice thickness. The highly dynamic nature of the Southern Ocean plus a generally thick and metamorphosed snow cover result in a complex vertical layering of the sea ice, and its thickness is difficult to derive using remote-sensing techniques. To improve the translation of satellite information, and capitalizing on near-coincident data collection as part of NASA's Operation IceBridge [OIB], we collected a range of in situ sea-ice (and ice-sheet) measurements off East Antarctica during austral spring 2019. Here we analyse a three-tiered dataset based on the ICESat2 laser profiles, OIB data from dual-colour laser altimeter, radars, as well as optical, hyperspectral, and thermal imagers and in situ transect measurements of sea-ice and snow thickness. The study was carried out on landfast ice, so that temporal offsets between measurements may be accounted using a column (thermodynamic) sea-ice model.