The statistics and sensitivity of a double-gyre model: the reduced-gravity, quasigeostrophic case

The sensitivity of the time-averaged circulation of an oceanic double-gyre model to variations in the model's parameters and forcing is studied. Unresolved low-frequency variability in the solution leads to statistical uncertainty in the estimates of the time-averaged quantities. The authors utilize bootstrap analyses of a number of multicentury integrations of a reduced-gravity, quasigeostrophic, eddy-resolving ocean model to estimate these statistical uncertainties. An analysis is then presented of the sensitivity of the system to variations in the strength and asymmetry of the wind forcing and to variations in several other physical and numerical parameters of the system. The bootstrap results enable us to estimate error bounds on these sensitivities. The physical measures of the system investigated include the means and variances of the total energy, the peak transport, the location of the separation point, and the penetration scale of the free jet.