Arctic Snow Depth, Ice Thickness, and Volume From ICESat-2 and CryoSat-2: 2018–2021

Abstract

Using ICESat-2 and CryoSat-2 freeboards, we examine the variability of monthly Arctic sea ice snow depth, thickness and volume between October 2018 and April 2021. For the 3 years, satellite-derived estimates captured a decrease in mean April snow depth (∼2.50 cm) and ice thickness (∼0.28 m) equivalent to an ice volume loss of ∼12.5%. Results show greater thinning of multiyear ice with an end-of-season thickness in 2021 that is lower by ∼16.1% (0.50 m), with negligible changes over first-year ice. For the period, sea ice thickness estimates using snow depth from climatology result in thicker ice (by up to ∼0.22 m) with a smaller decrease in multiyear ice thickness (∼0.38 m). An 18-year satellite record, since the launch of ICESat, points to a loss of ∼6,000 km3 or one-third of the winter Arctic ice volume driven by decline in multiyear-ice coverage in the multi-decadal transition to a largely seasonal ice cover.