Salinity And Stratification at the Sea Ice Edge (SASSIE)

Sea ice extent in the Arctic Ocean has declined dramatically over the past decades. Autumn ice advance is slower and occurs later, while summer ice retreat is faster and occurs earlier. The result is a lengthening open-water period each year, leading to changes in air-sea heat and momentum fluxes, the freshwater cycle, surface albedo feedbacks, primary production, and regional and global climate as well as human and ecological health.

Our experiment will examine how summer ice melt evolves into and is inexorably linked with autumn sea ice advance, focusing on:

• Quantifying the salinity anomalies generated by melting ice, how they evolve in time, and how they affect stratification, sea surface temperature (SST), and subsequent ice advance;
• Exploring these processes using a series of model experiments; and
• Collecting data to enable improved satellite sea surface salinity (SSS) retrievals in polar oceans, and linking the in situ salinity signals with those observed from satellites.

SASSIE will address its science themes in a multi-scale in situ, airborne, satellite, and modeling experiment. The primary aim of the field campaign is to capture the upper ocean structure during the transition from summer sea ice retreat to autumn sea ice advance. We will quantify the strength, size, and depth of fresh near-surface anomalies resulting from melting ice; the horizontal and vertical structure of those fresh anomalies as they evolve due to air-sea fluxes and waves, ocean currents and mixing; and the ocean conditions and the presence of sea ice as it begins to form.

See the main project site here: https://salinity.oceansciences.org/sassie.htm