HF skywave radar studies of ocean wave directional spectra near equilibrium

The author describes how the JINDALEE radar, together with a new wave directional spectrum estimation algorithm, is being used to study sea surface conditions near equilibrium. The angular spreading behaviour is of prime interest, since this attribute is poorly understood. Central to this investigation is the acquisition of sea clutter Doppler spectra over a range of radar frequencies spanning more than two octaves. Regional scale homogeneity of the wave field is a pre-requisite, a condition which cannot be verified with an HF groundwave radar. Ionospheric propagation conditions do not often allow high quality data to be collected over such a wide band, but the database includes five suitable datasets