[22-Feb-2024] Pérez Valentín, J., Gaube, P., Steele, M., Thomson, J., Pacini, A., and Zippel, S.
Presented at the 2024 Ocean Sciences MeetingAs sea ice melts during the Arctic summer, the underlying ocean stratifies and a distinctive layer of fresh, cold water forms at the surface. By late summer, the input of solar radiation decreases, and then in early autumn the heat stored in the ocean mixed layer begins to be released into the atmosphere. This air-sea exchange is modulated by turbulent air-sea fluxes and mixing in the upper ocean. As our planet warms, progressively less sea ice survives the summer, resulting in thinner winter ice packs. This creates a positive feedback increasing heat fluxes from ocean to atmosphere which can affect sea ice growth over the winter. The sea ice growth rate is tightly coupled to heat fluxes from the ocean to the atmosphere as it is determined by the energy balance at the lower boundary of the ice. Therefore, understanding how the air, sea, and ice interact during the turnaround period in the Arctic is critical for predicting sea ice formation. Surface radiative and turbulent heat fluxes were used from ERA5 reanalysis data to define the Arctic turnaround as the time when the upper ocean and lower atmosphere are at a mean thermal balance (i.e., the net heat flux is essentially zero). We analyze a suite of surface meteorological parameters such as wind speed, air temperature, and sea surface temperature and compare them with local sea ice conditions. A study case is developed for the 2022 Arctic turnaround period (ATP) using data collected during the NASA-sponsored Salinity and Stratification at the Sea Ice Edge (SASSIE) field experiment in the Beaufort Sea. Surface stratification and air-sea flux observations are used to understand the large-scale response from regional-scale processes during the ATP.