Continuous, Array-Based Estimates of Atlantic Ocean Heat Transport at 26.58N

Continuous estimates of the oceanic meridional heat transport in the Atlantic are derived from the Rapid ClimateChange–MeridionalOverturningCirculation (MOC) andHeatfluxArray (RAPID–MOCHA)observing system deployed along 26.58N, for the period from April 2004 to October 2007. The basinwide meridional heat transport (MHT) is derived by combining temperature transports (relative to a common reference) from 1) the Gulf Stream in the Straits of Florida; 2) the western boundary region offshore of Abaco, Bahamas; 3) the Ekman layer [derived from Quick Scatterometer (QuikSCAT) wind stresses]; and 4) the interior ocean monitored by ‘‘endpoint’ ’ dynamic height moorings. The interior eddy heat transport arising from spatial covariance of the velocity and temperature fields is estimated independently from repeat hydrographic and expendable bathythermograph (XBT) sections and can also be approximated by the array. The results for the 3.5 yr of data thus far available show a mean MHT of 1.33 6 0.40 PW for 10-day-averaged estimates, on which time scale a basinwidemass balance can be reasonably assumed. The associated MOC strength and variability is 18.5 6 4.9 Sv (1 Sv [ 106 m3 s21). The continuous heat transport estimates range from a minimum of 0.2 to a maximum of 2.5 PW, with approximately half of the variance caused by Ekman transport changes and half caused by changes in the geostrophic circulation. The data suggest a sea