CFOSAT Along-Track Data Based Scaling And Coupling Analysis Of Wind Speed And Wave Height

The lack of understanding to the dynamic processes of air-sea interaction is one of the main reasons of uncertainty in climate models.The interaction between ocean surface wind and waves determines the exchange of energy,heat,and mass.However,the complex multiscale dynamic processes of wind and waves involve spatial scales ranging from meters to thousands of kilometers,corresponding to the scaling features.Meanwhile,due to the existence of nonlinear interactions between different scales,there are also transformation and exchange of physical quantities,such as energy and enstrophy,forming complex turbulent cascade processes.Due to the lack of wind and wave observational data and scientific methods,the researches on the scaling of wind and waves,energy flux and wind-wave coupled relationship are limited.While,these studies are vital to the understanding of the dynamic characteristics of the sea surface processes in the air-sea interaction.The China-France Oceanography Satellite(CFOSAT)provides simultaneous observations of wind and wave for the study of air-sea interaction.Based on these data,this study develops three new methods in the following works:1)For the discontinuity data induced by factors such as lands or bad measurements,an improved Fourier power spectrum algorithm is proposed based on the Wiener-Khinchine theorem.Then the spectra for satellite along-track wind and wave are measured to study the scaling features at the scale of 100-3,000 km.2)Improve the turbulence model independent filter-space-technique to process the wind data which contain gaps,and obtain the features for energy and enstrophy fluxes of the atmospheric movements at the scale of 12.5-500 km.3)Propose a probability-based swell identification method without the wave spectrum data,and establish a unified wind-wave power-law relationship model.In summary,the scaling features for CFOSAT along-track wind and waves are examined;the scale-to-scale energy and enstrophy fluxes for wind field are obtained;a probability-based swell identification method is proposed,and an improved wind-wave power-law relation is established.The results obtained in this thesis not only enrich the fundamental knowledge of ocean surface processes,but also provide a benchmark for either oceanic or atmospheric model.