Circulation Changes in the Arctic Ocean and Subarctic Seas and their Connections to the Global Ocean and Climate

In recent decades we have seen major changes in Arctic Ocean circulation, salinity, temperature, and sea ice. There is evidence of connections between these changes and climate indices, the radiative heat balance, and the strength of the global overturning circulation. Given the limited in situ monitoring of the Arctic region, these effects could not be properly studied, and only recent satellite-derived measurements and models have allowed for potential enhancement, although their validity in the Arctic region is still debated. The change of climate has become more obvious in the last few decades due to improved observation with these models and satellites. Given the possible role of Arctic Ocean outflow in controlling global overturning circulation, there have been extensive efforts in recent years to monitor fluxes between the subarctic seas and the Arctic Ocean. However, definitive trends remain challenging to observe due to spatiotemporal variability. Satellite-derived salinity can assess the freshening of the Arctic waters due to ice melt. In this proposal we will derive freshwater fluxes from NASAs Soil Moisture Active Passive (SMAP), the ESAs Soil Moisture Ocean Salinity (SMOS), and a suite of models: FSUs Arctic Ocean Hybrid Coordinate Ocean Model (AO-HYCOM); NASA/JPLs Estimating the Circulation and Climate of the Ocean (ECCO); Global Nucleus for European Modeling of the Ocean version 3.4 (NEMOv3.4), NOAA/NCEPs Climate Forecast System version 2 (CFS2.0), and reanalysis products using Simple Ocean Data Assimilation (SODA), and Ocean Reanalysis System 5 (ORAS5), and to investigate the impact of freshwater outflow from the Arctic Ocean on stratification and overturning in the subarctic seas. We will compare these values with evaporation, precipitation, and sea surface temperature to study the effects of these properties on freshwater fluxes. In addition to freshwater fluxes, many other properties in the Arctic Oceacluding sea surface temperature, ocean heat content, winds, and sea surface height. To understand the decadal and recent variability within the Arctic Ocean, we will be looking at these different properties using satellite-derived measurements and models. The climate and circulation in the Arctic region are very dependent upon the strength and phase of climate patterns. The Arctic Oscillation and the related North Atlantic Oscillation both have a large impact on the Arctic region. The El Nio Southern Oscillation (ENSO), a tropical phenomenon, has global influence, however its impact in the Arctic region is poorly understood. These climate patterns can help explain interannual and decadal changes in the Arctic, and possibly hiatuses seen in long-term trends. The proposed research work explores the state of knowledge and gaps in understanding of the Arctic Ocean and its connection with subarctic seas, to advance our conception of the relation between changes in the Arctic Ocean and global ocean circulation and climate. The overarching objective of this proposal will be to understand the inter-annual and longer-term variations in the Arctic Ocean and subarctic seas and their connections to the global ocean. We identify the below key questions for understanding the role of Arctic and subarctic waters in changing the global ocean in response to climate forcing: 1) What is the impact of freshwater outflow from the Arctic Ocean on stratification and overturning in the subarctic Seas? 2) What are the impacts of decadal variability within the Arctic Ocean on global ocean and climate? 3) What proportion of Arctic Ocean variability is linked to variations in the climate indices (AO, NAO and EN