Presenter: Kyla Drushka (Applied Physics Laboratory, University of Washington)

Description:
In the salinity-stratified Arctic Seas, relatively cold and fresh waters sit above warmer, saltier waters. Variations in upper ocean salinity and stratification can thus modulate the ventilation of stored subsurface heat, which can affect sea ice formation and melt.  For instance, stratification generated by surface freshening can suppress upward mixing of heat from the warmer subsurface waters, thereby enhancing surface cooling and providing favorable conditions for sea ice growth; in contrast, mixing from wind and waves can disrupt stratification, releasing subsurface heat and melting sea ice. These ocean-ice-atmosphere interactions may be important for understanding and predicting spatio-temporal patterns of sea ice changes under a warming climate, but these interactions are difficult to observe and model – particularly very near the ocean surface, where signals are strong. We hypothesize that sea surface salinity and stratification anomalies generated by summer sea ice melt can precondition the ocean for sea ice formation, and thus that surface salinity can be an important predictor for autumn ice advance. A new NASA project, Salinity and Stratification at the Sea Ice Edge (SASSIE), will test this hypothesis in the Beaufort Sea in 2022 by examining how summer ice melt evolves into and is inexorably linked with autumn sea ice advance. Using a combination of intensive in situ and airborne measurements, satellite observations, and numerical ocean model experiments, SASSIE will focus on quantifying the salinity anomalies generated by melting sea ice, how they evolve in time as a result of atmospheric forcing and ocean processes, and how they affect stratification, sea surface temperature, and subsequent ice advance. Here, we present the upcoming SASSIE experiment and show early results from analysis of satellite observations and model simulations that examine the links between salinity, temperature, atmospheric forcing, and sea ice variability in the Beaufort Sea.