Operational tools for deriving wind and wave joint occurrence probabilities as well as wind and wave persistence duration statistics from satellite observation data are presented. These statistics are very useful for the preparation and the analysis of marine operations and the methodologies presented in the paper show how they can be derived from satellite data or from other sources. The methods of analysis are based on the application of Plackett distribution model to calculate the joint probabilities and on the application of Markov process theory to derive persistence statistics of simultaneous wind and wave conditions.
Empirical marginal and joint probability distributions of wind and wave can be derived from satellite observations (altimetric data) on a routine basis, for any maritime area. But, if Weibull models usually represent marginal distributions of wind and wave in various applications, there are no usual parametric models of their joint distribution, although such joint distributions can be useful for applications such as studies of marine operations. In addition, statistics of persistence duration are also of prime importance for the design of marine operations, but they cannot be derived directly from satellite data, because satellite repeat cycles are too long. The paper shows that joint occtwrence of wind and wave can be modelled by Plaekett distribution, with parameters derived from satellite data. It shows also that, using this distribution model and persistence duration modelled according to Markov process theory, accurate information on the risks of bad operational conditions and their duration can be derived from satellite data. Note however that complementary data are requested to estimate transition matrix parameters for application of Markov process. The method is very useful for the preparation of marine operations. Tests carried out for diving operations with the Nautile, a French oceanographic manned submersible.