Variability of freshwater and volume fluxes in Fram Strait from observations and numerical simulations

Dmitry S Dukhovskoy, Florida State University, Tallahassee, FL, United States, Paul G. Myers, University of Alberta, Department of Earth and Atmospheric Sciences, Edmonton, AB, Canada, Laura de Steur, Norwegian Polar Institute, Tromsø, Norway and Wieslaw Maslowski, Naval Postgraduate School, Monterey, CA, United States
Abstract:
Freshwater fluxes from the Arctic Ocean impact thermohaline processes and deep convection in the subpolar North Atlantic (SPNA) and can play a significant role in the Arctic and subarctic climate variability. There are two major routes of Arctic freshwater to the SPNA through Fram Strait and through Canadian Arctic Archipelago via Davis Strait. Observations demonstrate increasing freshwater content of the Arctic Ocean since the late 1990s. Along with the increasing Arctic freshwater content, no increasing trend in the liquid freshwater export to the SPNA was observed in the Davis Strait and Fram Strait during the 2000s until 2009. Mooring observations in Fram Strait demonstrate an overall increase of liquid freshwater transport from the Arctic Ocean during 2009–2016. During this time period, the annual freshwater flux (relative to salinity of 34.9) increased from ~1500 km3 yr--1 to 2400 km3 yr-1. Due to limited (in space and time) observations in the straits as well as relocation of the mooring observations in Fram Strait during the period of observations, there is uncertainty in the freshwater and volume transport estimates derived from the mooring records. We use several high-resolution numerical models (4-km and 2-km HYCOM-CICE, 2-km NEMO, and 2-km RASM) to investigate seasonal and interannual variability of the freshwater and volume fluxes in the Fram Strait during 2000-present. The model-based estimates will be compared to the estimates derived from the mooring observations in the Fram Straits. Next, model experiments are used to investigate uncertainty in the freshwater and volume flux estimates derived from the mooring observations. Specifically, we will investigate the uncertainty related to the fluxes over shallower shelf regions that are possibly underrepresented in the mooring observations.