Here, I demonstrate that AVISO-like quantities such as the relative vorticity ζ and the strain (as well as their combination, the Okubo-Weiss parameter) are inadapted to locate the submesoscale structures (seen in the full resolution ζ). I use for this a snapshot of the 1/25th deg. HYCOM simulation.
Figure 1: ζ on Jan. 15, 2010, deduced from the full-resolution surface geostrophic velocity field.
Figure 2: As in Fig. 1 but from AVISO-like geostrophic flow. AVISO-like quantities are the low-pass filtered version of the full resolution quantity, the filter keeping wavelengths longer than 150 km.
Figure 3: As in Fig. 1 but for the strain.
Figure 4: As in Fig. 2 but for the strain.
See fsle_HYCOM.m in RESEARCH/PROJECTS/MARINE_BIOLOGY/SUBMESOSCALE_PROCESSES/FSLE/analysis/HYCOM on ipu1.