Here, I show that the gradient of sea surface temperature (SST), which locates where there are density fronts, is correlated with the stratification N witin the surface mixed layer. Fig. 1 shows the gradient and, in Fig. 2, it is plotted with contours of N. For most of the events, the two are well correlated. This is demonstrated by a scatter plot for a subdomain northeast of Hawaii in Fig. 3.
Figure 1: Gradient of SST on Jan. 15, 2010 in HYCOM.
Figure 2: Contours of N at 10 m depth superimposed onto the gradient of SST on Jan. 15, 2010 in HYCOM.
Figure 3: N (at 10 m depth) versus the gradient of SST from a region northeast of Hawaii on Jan. 15, 2010 in HYCOM.
Fig. 4 and 5 show that outside Spring, for instance in Summer, the SST gradient is much weaker and it is not well correlated with N.
Figure 4: Same as Fig. 2 but for Jul. 15, 2010.
Figure 5: Same as Fig. 3 but for Jul 15, 2010.
Computed using rel_vort_HOT_track.m in RESEARCH/PROJECTS/MARINE_BIOLOGY/SUBMESOSCALE_PROCESSES/HYCOM/analysis/rel_vort_HOT_track/ on ipu1.