On the mean meridional transport of energy in the atmosphere and oceans as derived from six years of ECMWF analyses

Abstract

The global ECMWF analyses for the period 1981–86 are used to compute the mean meridional transport of moist static energy in the atmosphere. The results show that the recurring changes made to the analysis procedure over the years have led to a significant increase in the transport due to the mean meridional circulation in the tropics. Compared to the earlier radiowind data based results of Oort and Peixóto, the use of analyses resulting from the data assimilation system leads to larger poleward transports; these amount to about 4 × 10¹⁵ W (compared to 3 × 10¹⁵ W) near 45° of latitude in both hemispheres in the annual mean. The subtraction of the mean atmospheric transport from the total ocean-atmosphere transport implied by the Nimbus 7 ERB NFOV net radiation flux at the top of the atmosphere leads to a maximum annual northward ocean heat transport of 3.2 × 10¹⁵ W at 20°N. This value exceeds by 1 × 10¹⁵ W or more the values obtained using surface marine data and bulk aerodynamic formulae in previous studies.