Yana Bebieva, a Ph.D. candidate in geology and geophysics at Yale University, will give a talk titled, “Double-diffusive mixing in the Arctic Ocean.”
State-of-the-art coupled climate models show major disagreements with observations across a wide range of parameters of the Arctic system. Unresolved processes that require parameterization in numerical models might be the major cause of such discrepancies. In this talk, I will discuss a class of small-scale (sub-grid scale) convective mixing processes (double-diffusive processes) that are prevalent throughout the Arctic Ocean and are one of the main mechanisms by which deep ocean heat is fluxed upward to the surface ocean. Using ocean observations from the extensive Ice-Tethered Profiler dataset, temperature and salinity measurements of an Atlantic Water mesoscale eddy are analyzed to understand the effects of velocity shear on a range of double-diffusive processes. Estimated lateral variations in vertical fluxes across the eddy allow for speculation that double diffusion speeds up the eddy decay, having important implications for the transfer of Atlantic Water heat in the Arctic Ocean. Motivated by observations that show the coexistence of thermohaline intrusions and double-diffusive staircases, the origin of double-diffusive staircases in the Arctic Ocean is investigated for the particular background setting in which both temperature and salinity increase with depth.