Frequency and direction resolution in HF radar ocean wave measurements

Describes some simulation experiments that demonstrate that the methods used to extract the directional spectrum from HF radar data can identify bi-modality in both direction and frequency. Frequency and/or direction differences that allow the separation of distinct wave systems are discussed. Even when separation is not possible, those parameters of the directional spectrum that do not describe the detailed directional distribution of energy are extracted with good accuracy. Examples of bi-modal spectra measured during the NURWEC2 experiment are used to illustrate the temporal evolution of and interaction between the different wave systems