FN Archimer Export Format PT J TI Improvement ocean wave spectra estimation using the temporal structure of wave systems BT AF KPOGO NUWOKLO, Komlan Agbéko AILLIOT, Pierre OLAGNON, Michel GUEDE, Zakoua ARNAULT, Sabine AS 1:1;2:2;3:1;4:1;5:3; FF 1:PDG-REM-RDT-LCSM;2:;3:PDG-REM-RDT-LCSM;4:PDG-REM-RDT-LCSM;5:; C1 IFREMER, Ctr Brest, Lab Comportement Struct Mer, F-29280 Plouzane, France. Univ Bretagne Occidentale, Lab Mathemat Bretagne Atlant, Brest, France. Univ Paris 06, LOCEAN IPSL, Paris, France. C2 IFREMER, FRANCE UBO, FRANCE UNIV PARIS 06, FRANCE SI BREST SE PDG-REM-RDT-LCSM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france IF 2.841 TC 3 UR https://archimer.ifremer.fr/doc/00252/36309/37313.pdf LA English DT Article DE ;Directional wave spectrum;Spectral estimation;Periodogram smoothing;Kriging AB Sea states are usually the combination of several time-evolving wave systems whereas the classical spectral estimation methods assume stationarity. A method that adapts to the dynamical evolution of the spectral components is proposed to improve both omnidirectional and directional sea wave spectral estimations. In this method, periodograms are computed for each sea state as in the conventional methods, and rather than only smoothing individual periodograms, the overall time-history of periodograms are simultaneously smoothed in frequency and time dimensions. Since a simple two dimensional averaging would not be appropriate because the temporal evolution of the wave systems reflects typical non-stationary behaviors, we use either kriging or adaptive 2D kernel density estimators that allow the taking care of the spectral component frequency-time evolutions. The method is successfully validated on sequences of spectra typical of sea-state conditions in West Africa. The comparison with the simple 2D averaging method and individual periodogram smoothing method shows that the proposed method gives higher effective numbers of degrees of freedom, better estimates of the spectral shape and reliable spectral moments. The method also provides a tool for sea wave spectra interpolation and may thus be used to fill in missing values and improve wave systems tracking for storm identification purposes. PY 2015 PD FEB SO Coastal Engineering SN 0378-3839 PU Elsevier Science Bv VL 96 UT 000348262900009 BP 81 EP 91 DI 10.1016/j.coastaleng.2014.11.007 ID 36309 ER EF