Midlatitude North Atlantic heat transport: A time series based on satellite and drifter data

Using temperature, salinity, and displacement data from Argo floats combined with satellite sea surface height, a time series of the Atlantic meridional heat transport from January 2002 to August 2010 has been estimated for 41 degrees N. The calculation method is validated against hydrographic climatologies and output from the ECCO2 ocean data assimilation model, and the assumptions are shown to be reasonable; the greatest source of error is from the sparse distribution of Argo floats. The mean heat transport is 0.50 +/- 0.1 PW, which is consistent with previous estimates made using surface flux data but is low compared estimates from hydrographic cruise data. Consistent with results from the RAPID array, the heat transport has a significant annual cycle and high degree of subannual variability, indicating that statistical uncertainty in previous calculations may have been underestimated. There is little evidence of a trend over the short period of available data. Correlations with sea surface temperature suggest clear physical relationships between heat transport and SST, even on the short time scales of available data.