Using multifrequency HF radar to estimate ocean wind fields

HF radar has become an important tool for mapping surface currents in the coastal ocean and has been used to determine wind direction. Here the author investigate further the ability of multifrequency HF radar to measure the vector wind field and the impact that such measurements have on the measurement of coastal wind fields over both the land and sea. In this study the author use data collected over Monterey Bay, California from Jan. to Aug. 2001. Their multifrequency coastal radars (MCR´s) operated at 4.8, 6.8, 13.4 and 21.8 MHz, measuring currents at effective depths of about 2.5, 1.8, 0.9 and 0.6 m respectively. Here, the author move beyond their preliminary reports by examining the durability of their HF wind vector measurements over a seven-month data set. The results over this longer time span indicate standard errors of prediction (SEP´s) of 1.2 and 1.1 m/s for the U and V wind speed components respectively with biases less than 0.15 m/s. The author also investigate a Kalman filtering modification to their partial least squares algorithm. Further, the author demonstrate the beneficial impact of multifrequency HF radar, wind field measurements, on estimation of the coastal wind field over both land and sea.