Snow and ice thickness derived from sea ice mass balance buoys in the Transpolar Drift system

Abstract

Sea ice controls and is influenced by the exchange of energy, moisture and momentum between the underlying ocean and the lower atmospheric boundary layer. The physical properties of sea ice play a critical role in modulating these interactions. Of particular importance is the temporal evolution of the thickness of the ice and snow layers, both of which are a result of seasonally and spatially highly variable growth and decay processes. To investigate whether large-scale changes in the Arctic sea ice cover such as a general thinning and increased drift speeds are also imprinted on long term data sets from autonomous drifting platforms, we present an analysis of sea ice properties derived from sea ice mass balance buoys deployed in the transpolar drift system between 2012 and 2023, thus including the period of the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) experiment in 2019/20. In particular, we aim to assess whether the observed variations in sea ice mass balance by ice growth and melt in recent years are significantly different from previous years, or whether they remain consistent on an interannual time scale. To achieve this, a uniform processing scheme is developed and applied to large set of buoys with the aim to minimize methodological ambiguities in the derivation of snow–ice–ocean interfaces. We also present comparisons with external factors (both thermodynamic and dynamical) derived from satellite data and atmospheric reanalysis that influence the local sea ice mass balance observed by the buoys during their drift towards Fram Strait and adjacent seas.