FN Archimer Export Format
PT J
TI Joint estimation of balanced motions and internal tides from future wide‐swath altimetry
BT 
AF Le Guillou, Florian
   Lahaye, Noe
   Ubelmann, Clément
   Metref, Sammy
   Cosme, Emmanuel
   Ponte, Aurelien
   Le Sommer, Julien
   Blayo, Eric
   Vidard, Arthur
AS 1:1;2:2;3:3;4:1;5:1;6:4;7:1;8:5;9:5;
FF 1:;2:;3:;4:;5:;6:PDG-ODE-LOPS-OH;7:;8:;9:;
C1 Univ. Grenoble Alpes ,CNRS IRD Grenoble INP IGE Grenoble, France
   Inria & IRMAR campus universitaire de Beaulieu, Rennes, France
   Ocean Next ,Grenoble ,France
   Univ. Brest CNRS IRD Ifremer Laboratoire d’Oceanographie Physique et Spatiale (LOPS) IUEM, Brest, France
   Univ. Grenoble Alpes CNRS INRIA Grenoble INP LJK Grenoble ,France
C2 UNIV GRENOBLE ALPES, FRANCE
   INRIA, FRANCE
   OCEAN NEXT, FRANCE
   IFREMER, FRANCE
   UNIV GRENOBLE ALPES, FRANCE
SI BREST
SE PDG-ODE-LOPS-OH
UM LOPS
IN WOS Ifremer UMR
   DOAJ
   copubli-france
   copubli-univ-france
IF 8.469
TC 5
UR https://archimer.ifremer.fr/doc/00735/84741/89788.pdf
LA English
DT Article
DE ;sea;ocean surface;altimetry;data assimilation
AB Wide-swath altimetry, e.g. the Surface Water and Ocean Topography (SWOT) mission is expected to provide Sea Surface Height (SSH) measurements resolving scales of a few tens of kilometers. Over a large fraction of the globe, the SSH signal at these scales is essentially a superposition of a component due to balanced motions (BMs) and another component due to internal tides (ITs). Several oceanographic applications require the separation of these components and their mapping on regular grids. For that purpose, the paper introduces an alternating minimization algorithm that iteratively implements two data assimilation techniques, each specific to the mapping of one component: a quasi-geostrophic model with Back-and-Forth Nudging for BMs, and a linear shallow-water model with 4-Dimensional Variational (4DVar) assimilation for ITs. The algorithm is tested with Observation System Simulation Experiments (OSSE) where the truth is provided by a primitive-equation ocean model in an idealized configuration simulating a turbulent jet and mode-one ITs. The algorithm reconstructs almost 80% of the variance of BMs and ITs, the remaining 20% being mostly due to dynamics that cannot be described by the simple models used. Importantly, in addition to the reconstruction of stationary ITs, the amplitude and phase of nonstationary ITs are reconstructed. Sensitivity experiments show that the quality of reconstruction significantly depends upon the timing of observations. Although idealized, this study represents a step forward towards the disentanglement of BMs and ITs signals from real wide-swath altimetry data. Plain Language Summary Wide-swath altimetry, e.g. the Surface Water and Ocean Topography (SWOT) mission is expected to provide Sea Surface Height (SSH) images with pixels of 2 km, revealing motions at scales of a few tens of kilometers. At these scales, SSH variations are essentially due to the superposition of slow, balanced motions primarily constrain by Earth’s rotation, and fast, propagating motions due to internal waves mainly generated by interactions between bathymetry and tidal water displacements. Several oceanographic applications require the separation of these two SSH components and their mapping on regular grids. This paper presents an original method to achieve this separation, based on data assimilation approaches and simple dynamical models. Experiments with synthetic SSH images, simulated from an ocean circulation model with detailed physics, show the efficiency of the method. 
PY 2021
PD DEC
SO Journal Of Advances In Modeling Earth Systems
SN 1942-2466
PU American Geophysical Union (AGU)
VL 13
IS 12
UT 000739722900004
DI 10.1029/2021MS002613
ID 84741
ER

EF