Wave and current sensing by HF radar

A brief review of HF radio oceanography is given together with an assessment of the difficulties in extending this to include wave sensing. Various methods of estimating the two-dimensional spectrum of waves on the sea surface from one-dimensional radar Doppler spectra are considered and a technique is proposed based on the maximum entropy method. It is shown that if a pair of `vector¿ radars are used to provide two independent views of the same patch of sea then further information can be gained by operating the radars bistatically. Observations made at Flamborough Head in March 1986 are used to test a few of the basic properties of the theoretical bistatic cross-section of the sea surface.