Nowcast of surface currents from blending HF radar: inverse model, application to Monterey Bay

We formulate an approach to reconstruct surface circulation from a high-frequency (HF) radar data in open boundary areas. The approach uses flow decomposition through two scalar potentials, the self-consistent open boundary conditions, the cost function (penalty) for the validation of free model input and selective filter. The nowcast skill is enhanced through an ensemble averaging technique. The current nowcast in Monterey Bay was realized through the approach for August 1994. We demonstrate it has weak sensitivity to level of noise in the observations. The nowcast gives better understanding of inshore circulation, eddy activities and upwelling processes.