Carter, B. R., University of California, San Diego, La Jolla, USA, brcarter@ucsd.edu
Dickson, A. G., University of California, San Diego, La Jolla, USA, adickson@ucsd.edu
Talley, L. ., University of California, San Diego, La Jolla, USA, ltalley@ucsd.edu
Chereskin, T. ., University of California, San Diego, La Jolla, USA, tchereskin@ucsd.edu
Holte, J. ., University of California, San Diego, La Jolla, USA, jholte@ucsd.edu
Hartin, C. ., University of Miami, La Jolla, USA, chartin@rsmas.miami.edu
AN INVERSE MODEL TO SEPARATE MIXING FROM GAS EXCHANGE IN THE REGION OF AAIW FORMATION
Intermediate and mode waters have the potential to operate as rapid feedbacks to climate change via entrainment of greenhouse active species due to their comparatively fast turnover times. Estimating the gas exchange that occurs during formation of these masses is complicated by biological activity and the complex mixing of the source waters during subduction. In this study we estimate gas exchange using hydrographic data collected on a cruise to a region of suspected intermediate and mode water formation (the region contained by 62° S, 105° W and 45° S, 75° W) during the late Austral winter of 2005. An optimum multiparameter inverse model with Redfield-type biology, simple mixing, and no parameterization for gas exchange was used to obtain a modeled distribution of properties. The difference between this modeled distribution and the observed distribution then provides our estimate for the net effect of gas exchange over the timescale of mixing. Average rates of exchange are thus determined for deep mixed layer waters and waters representative of AAIW over this timescale.