Spectral content of nadir altimetry at regional scales: a case study in the Bay of Biscay and New Caledonia region

Mei-Ling Dabat (LEGOS, France)

CoAuthors

Nadia Ayoub (LEGOS, France); Lionel Gourdeau (LEGOS, France); Frederic Marin (LEGOS, France); Fabien Léger (LEGOS, France); Isabelle Pujol (CLS, France); Rosemary Morrow (LEGOS, France)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: Science III: Mesoscale and sub-mesoscale oceanography

Presentation type: Type Poster

Recent studies have investigated the spectral content of conventional altimetry data at low resolution (1 Hz) in order to characterize the seasonal and spatial variability of the nature of the surface dynamics (balanced vs unbalanced motions), of the noise level and of the data resolution among others (e.g. Fu et al., 2012; Zhou et al., 2015; Dufau et al., 2016; Vergara et al., 2019). All these studies were performed at global scale based on spectra representative of large areas (~ 10° square boxes).
In the present work, we propose to revisit such spectral analysis using high-resolution data (20 Hz/40 Hz) of the most recent satellite missions such as Jason 2, Saral/Altika and Sentinel 3A. The motivation is to extend the previous analysis to finer scales with regard to the next SWOT mission. We first summarize different available data sets and options in the processing: geophysical corrections, editing of data and corrections, smoothing. The extra information provided by high-resolution data is then explored in different datasets.
We focus on two specific regions: a subtropical area around New Caledonia in the western tropical Pacific and a middle latitude area which is the abyssal plain of the Bay of Biscay in the north-east Atlantic not investigated in the aforementioned papers. These regions have contrasted dynamics, but are both characterized by the presence of strong internal tides. The averaged spectra over these areas are first discussed in terms of the local dynamics, and their representativeness of the local dynamics is discussed in comparison with individual along track spectra. Indeed, anisotropic motions such as internal tides may induce different signatures in the different spectra.
 

Poster show times:

Room Start Date End Date
The Gallery Tue, Oct 22 2019,16:15 Tue, Oct 22 2019,18:00
The Gallery Thu, Oct 24 2019,14:00 Thu, Oct 24 2019,15:45
Mei-Ling Dabat
LEGOS
France
mei-ling.dabat@legos.obs-mip.fr