Wind-wave relationship from SEASAT radar altimeter data

Abstract

We present a nonlinear relationship between ocean surface wind at 10 m height (U ₁₀ ) and significant wave height of wind-generated gravity waves, (H _1/3)gw, over the open oceans using SEASAT radar altimeter data. The data represent a variety of fetches, durations and strength of winds. Concurrent measurement of significant wave height, (H _1/3 ), which may contain a measure of swell and U ₁₀ obtained from the processed geophysical data record (GDR) of the SEASAT radar altimeter were used in the analysis. The total wave energy, E _alt, characterised by altimeter H ^1/3 measurements was compared with the energy of a fully developed sea, E _fd derived from U ₁₀measurements using the Pierson-Moskowitz model. The criteria E _alt ≤ E _fd was used in data selection to minimise the influence of swell. (H _1/3)gw thus obtained was used in a regression in terms of U ₁₀ in a second-degree polynomial. Verification with independent radar altimeter data confirmed the validity of the proposed wind-wave model, which could be used for operational wave forecasting.