MODEL-CALCULATED SEASONAL TRANSPORT VARIATIONS THROUGH THE FLORIDA STRAITS - A COMPARISON USING DIFFERENT WIND-STRESS CLIMATOLOGIES

A linear, barotropic model of the North Atlantic at 1 degrees X 1 degr ees resolution is employed to investigate the effect of using differen t wind-stress climatologies on the model response at the Florida Strai ts. The wind-stress climatologies are those of da Silva et al. (DS), H ellerman and Rosenstein (HR), Isemer and Hasse (IH), and Trenberth et al. (TR). For each climatology, the model shows maximum northward tran sport in the summer and minima in the fall and late winter, in general agreement with transport measurements from cable data (Larsen). Howev er, the amplitude of the model response differs considerably between t he climatologies. In the case of DS the range (maximum transport minus minimum transport) is 2.8 Sv ( 1 Sv equivalent to 1 X 10(6) m(3) s(-1 )); HR: 3.6 Sv, TR: 5.2 Sv, and IH: 5.9 Sv, compared to a range of 4.6 +/- 0.3 Sv derived from cable data. The increased range in the IH cas e compared to HR is in general agreement with the finding of Boning et al. using the Kiel version of the model that forms the WOCE Community Modelling Effort. However, whereas Boning et al. claim that winds nor th of 35 degrees N have little influence on the seasonal response of t heir model at the Florida Straits, it is found that winds north of 35 degrees N play an important role in the model presented here. The reas on for the behavior bf the community model is not clear but may be ass ociated with advection by the western boundary current, an effect not present in the linear model discussed here. In the case of the present model, the importance of forcing by the meridional component of the w ind is shown, although forcing through the zonal component also plays some role in explaining the differences between the cases run under th e different climatologies. The importance in the model of forcing asso ciated with the meridional component of the wind along the continental slope region to the north of the straits is emphasized.