Recent Trends in Sea Ice Thickness from New Satellite Products

Sea ice extent and thickness play a significant role in the weather and climate of the polar regions, affecting the exchange of energy and mass between the atmosphere and the ocean. Sea ice directly impacts society with regard to marine transportation, hazards, recreation, fisheries, and subsistence hunting. Unfortunately, conventional observations of sea ice properties are sparse. Thus, satellite remote sensing data play a key role in estimating and monitoring changes in the sea ice of both polar regions.

With recent advances in remote sensing technology, it is now possible to estimate ice thickness from space using a variety of techniques, each having distinct advantages and disadvantages. One approach, the One-dimensional Thermodynamic Ice Model (OTIM), estimates ice thickness through a complex formulation of the surface energy budget. OTIM is driven by satellite products derived primarily from visible and infrared data, and can therefore be applied to the multidecadal record from weather satellites. It has exhibited a sufficient level of accuracy for the analysis of ice thickness trends. Other approaches to estimating ice thickness from space utilize laser and radar altimeters, which measure ice elevation (freeboard), and passive microwave data.

In this study we apply the OTIM method to 33 years of Advanced Very High Resolution Radiometer (AVHRR) data and compare the results to ice thickness from the ICESat laser altimeter, the CryoSat-2 radar altimeter, altimeters on IceBridge aircraft flights, and the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS). The comparisons are done over the Arctic Ocean for the period of overlap between all datasets. We then examine ice thickness trends and variability in the multidecadal AVHRR record for both the Arctic and Antarctic in September and April. Given the significant changes in sea ice cover in recent decades, we address the question of how sea ice thickness and volume have changed.