Differences between ASCAT, OSCAT and QuikSCAT derived vorticity: Implications on spatial resolution

Scatterometer derived area-averaged vorticity is calculated and compared for the ASCAT, OceanSat-2 (OSCAT) and QuikSCAT scatterometers. All scatterometer capture similar large scale features. There are two key differences; (1) coverage, and (2) small scale features. Differences in noise of the vorticity and rain-flagging (for low quality observations) are identified in images and through spectral analysis. Noise is shown to be an uncomfortably large player when the vorticity is averaged over the two smallest spatial scales. Averaging over a rough circle with a diameter of three grid cells greatly reduces the noise. Consequently, the averaging scale and noise must be considered when combining data from different scatterometers.