Revised Global Wave Number Spectra From Recent Altimeter Observations

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Vergara, Oscar, Morrow, Rosemary, Pujol, Isabelle, Dibarboure, Gérald, Ubelmann, Clément
• Other Authors: Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales Toulouse (CNES)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: satellite altimetry; mesoscale variability; energy cascade; internal waves; space oceanography; [SDU]Sciences of the Universe [physics]; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Antarctic; The Antarctic; Antarc*
• Online Access: https://insu.hal.science/insu-03670751; https://insu.hal.science/insu-03670751/document; https://insu.hal.science/insu-03670751/file/JGR%20Oceans%20-%202019%20-%20Vergara%20-%20Revised%20Global%20Wave%20Number%20Spectra%20From%20Recent%20Altimeter%20Observations.pdf; https://doi.org/10.1029/2018JC014844

International audience Global sea surface height wave number spectra are revisited using the most recent, lower-noise satellite altimeter missions from Saral/AltiKa and Sentinel-3 and compared to Jason-2 wave number spectra. Spectral preprocessing is configured to minimize the spectral slope distortion in the mesoscale wavelength range. A geographically variable wavelength range is used to calculate the spectral slopes, taking into account the regional eddy length scales based on the local Rossby radius. This dynamical wavelength range increases the spectral slope by 0.5 in middle to high latitudes, compared to a fixed wavelength range, and by -1.0 to 1.0 in different regions of the intertropical band. Using this dynamical wavelength range, mean sea surface height wave number spectra for these lower-noise missions exhibit low slope values (k -2 ) in the intertropical band, values of k -11/3 in the midlatitudes, and reaches k -5 in the subpolar regions and the Antarctic circumpolar current. An important seasonality is also revealed, with mesoscale spectral slope amplitudes decreasing in winter by 0.5 to 1.5 compared to summer, for the middle- to high-energy regions. A phase-locked internal tide correction is tested but has only a small impact on the spectral slope estimates when using the dynamical wavelength range.