The Southern Ocean is a significant component of the global overturning circulation and of the oceanic carbon cycle yet it is also a region where there are few in-situ observations, large uncertainties, and the potential for important climate feedback mechanisms. This study uses the 15+ years of available radar altimeter data, high-resolution ocean state estimates from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, and in-situ data (hydrography and Argo floats), in order to study time changes in the formation of Antarctic Intermediate Water (AAIW). This is a step towards an improved description and understanding of Southern Ocean airsea exchange processes, a prerequisite for improved representation of these processes in numerical climate models, and for more reliable predictions of how these processes might respond to changes in Greenhouse gas forcing. Specifically our study will (i) estimate interannual changes in Antarctic Circumpolar Current (ACC) frontal locations and their relation to Antarctic Intermediate Water (AAIW) formation rates, (ii) better describe and understand processes responsible for the ventilation of intermediate waters, and (iii) quantify the sensitivity of ACC frontal variability and of AAIW formation rates to changes in wind patterns. This research provides feedback to the ECCO2 project towards improving the representation of intermediate water formation, it complements ongoing and planned Climate Variability and Predictability (CLIVAR) efforts to better observe and understand climate-related variables in the Southern Ocean, it is consistent with the NASA strategic objective to "understand the role of oceans, atmosphere, and ice in the climate system and improve predictive capability for its future evolution", and it addresses the first research theme in the ROSES-2007-A07 by "supporting studies in physical oceanography utilizing Jason/OSTM mission data, as well as the combined 15-year TP/Jason data, preferably jointly with other satellite and in situ data and/or models, in support of basic research".
Altimeter Data And ECCO2 Ocean State Estimates Used To Study The Variability Of Antarctic Circumpolar Current Fronts And The Formation Of Antarctic Intermediate Water