Vector wind field measurements using multifrequency HF radar

It is well known that HF radars are capable of measuring wind direction by using the relative strength of the echoes from the approaching and receding ocean waves at the Bragg resonant wavelengths. Here we examine the ability of multifrequency HF radar to measure wind speed as well as direction. In this study we use data collected over Monterey Bay, California in December of 2000. At that time the M1 buoy (deployed by the Monterey Bay Aquarium Research Institute, MBARI) measured wind speed and direction. Two multifrequency coastal radars (MCR´s) operated near Santa Cruz and Moss Landing, California. Using the method of partial least squares we developed an algorithm for estimating the surface wind vector from multifrequency HF radar data. Comparison with surface truth from the M1 buoy indicates that the method produces excellent results. The wind speed was estimated with a standard error of prediction of a little over 1 m/s, bias of ≈0.5 m/s and R² of 0.71. We think that this method will rind useful application in measuring the detailed structure of the wind field in coastal regions on a few kilometer size scale.