The difference is too large to be attributed to uncertainties in the wind speed and the transfer coefficient. Figure 13 shows the net heat flux from atmosphere to ocean averaged from 1984 through 1987. There is considerable uncertainty in all components of the heat and freshwater fluxes. However, a relatively accurate assumption is that over an annual cycle, the global averages of the net fluxes are near zero. The latter shows more cooling in the Gulf Stream and Kuroshio extensions.
Some differences are due to the different corrections made to achieve global balance.
The correction to specific humidity increases evaporation by about 20 percent. A freshwater balance is then achieved by increasing precipitation by a uniform factor of 10 percent, which brings the MSU into better agreement with other precipitation climatologies. The resulting annual average global net freshwater flux is shown in Figure 14 . As desired, a near zero global annual average has been achieved. The advantages noted for the heat flux fields of Figure 13 also are valid for the freshwater flux field.