Correlation in relative vorticity between model output and eSQG for the North Equatorial Pacific in OFESΒΆ
The spatial correlation in relative vorticity between the model and eSQG output over a set of 5 deg. by 5 deg. regions centered on 4.5N, 9.5N and 14.5N and across the Pacific between 130E and 120W has been calculated and its zonal average is plotted in Fig. 1. The correlation decreases equatorward at all depth.
Figure 1: 2004 mean correlation in relative vorticity between the model and eSQG output. The correlation has been calculated for a set of 5 deg. by 5 deg. regions centered on 4.5N, 9.5N and 14.5N and across the Pacific between 130E and 120W. The correlation has then been averaged zonally in Fig. 1.
The mean correlation is relatively constant zonally, and the correlation is itself relatively constant in time (not shown). The only significant time and zonal variability is observed for the most equatorward region, for which the correlation falls to zero in the middle of the basin in Summer, and shows tendency to westward propagation (Fig. 2).
Figure 2: Correlation in relative vorticity between the model and eSQG output for the regions centered at 4.5N during 2004.
Snapshots of relative vorticity from the model and from eSQG for the region centered at 182,5E and 4.5N for three depths are shown in Fig. 3. This time and place were chosen for their relatively high correlation, so it should be consider as a good prediction by eSQG of relative vorticity. eSQG succeeds to reproduce some of the model features at the surface but as expected from the above results, the prediction accuracy falls quickly with depth.
Figure 3: Snapshot of relative vorticity near 182.5E, 4.5N on 11/01/2004 from the model (left) and eSQG (right): (upper) surface, (middle) 100 m, (lower) 320 m.