The implications of uncertainties in HF radar observations for measuring small-scale surface current structures

The uncertainties and errors in observations from oceanographic HF radars have implications for the minimum spatial resolution the radars can obtain. Individual oceanographic HF radars measure ocean currents on a polar grid, producing velocity observations as a function of range and bearing. Our recent work quantifying uncertainty in 'direction finding' HF radars demonstrates that most of the measurement errors are in the bearing measurement, a property that is similarly true for beamforming radars (BF) after considering the azimuthal resolution. We explore the implications of this fact for producing observations of submesoscale structures, vorticity, and divergence, aiming to address the following questions: 1) Is there an optimal set of signal processing parameters that minimize the errors for the majority of deployed HF radar systems? 2) What do the errors need to be in order to observe vorticity and divergence on 'small' temporal and spatial scales? 3) Can we make recommendations about the characteristics of future radars? 4) What fundamentally determines and/or limits the spatial resolution of the observations? 5) Are present methods for obtaining the total vector adequate for maintaining the resolution of the radial components? These questions are explored with simulated HF radar data, as well as with observations from SeaSondes and 8-channel radar systems.