Salinity, Heat and Freshwater Fluxes Across the Atlantic at 26°N: Time Series and Their Variability
[26-Feb-2014] McDonagh, E.L., King, B.A., Bryden, H.L., Johns, W.E., and Nurser, A.G.
Presented at the 2014 Ocean Sciences Meeting
We present a seven-year time-series of oceanic heat and freshwater fluxes across 26°N in the Atlantic between 2004 and 2011. The time series are constructed using observations from the RAPID-MOCHA array, Argo profiles and surface wind estimates from the ERA-reanalysis. Heat and freshwater fluxes have a mean and standard deviation of 1.25 ±0.37 PW and -0.35 ±0.22 Sv respectively. Variability in the Atlantic meridional overturning circulation (AMOC; as measured by the 26°N array) describes in excess of 90% and 80% of the variability in the heat and freshwater flux respectively. Once the mean sensitivity to the AMOC is removed we observe a systematic (in time) increase in the heat flux and reduction in the freshwater flux. These changes have a range of 0.12 PW and -0.09 Sv between 2004/2005 and 2009/2010. The structure in the residual is associated with changes in the transport-weighted salinity and transport-weighted temperature in the upper-ocean (top 1000m) interior. We examine the forcing mechanisms associated with these changes in temperature and salinity structure.