De-aliasing of tidal signals using wide-swath sun synchronous orbits

Loren Carrere (CLS, France)

CoAuthors

Florent Lyard (LEGOS, France); Clement Busche (CLS, France); Mathilde Cancet (NOVELTIS, France); Nicolas Picot (CNES, France)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: Tides, internal tides and high-frequency processes

Presentation type: Type Poster

Thanks to its current accuracy and maturity, altimetry is considered as a fully operational observing system dedicated to scientific and operational applications. In order to access the targeted ocean signal, altimeter measurements are corrected for several geophysical parameters among which the ocean tide correction is one of the most critical. The accuracy of tidal models has been much improved during the last 20 years, and in this context, a new global tidal model, FES 2014, has been developed and finalized in 2016 and it is now available on AVISO website :
https://www.aviso.altimetry.fr/en/data/products/auxiliary-products/global-tide-fes.html.
Some errors still remain mainly in shelf seas and in polar regions where availability of new databases is still worthful for the development of future tide models.

In this context and knowing that the tides and tidal currents are a predominant signal in shallow and shelf regions which have critical applications and societal interests, we analyse the interest of new satellite missions for the observation of tidal signals.

It is well-known that sun-synchronous orbits (SSO) do not sample properly the tidal signal, leading to bad aliasing frequencies of most tidal waves, and some solar waves are not even observable (S1 and S2).
As some of future SSO will benefit from wide-swath measurements of SSH or even surface currents (WISA, SKIM), we propose an estimation of the observability of tidal signals while taking into account the local multiple sampling allowed by the wide-swath of those new missions. The WISA constellation flying context is also taken into account.
The analysis is based on OSSE experiments using the IBI36 regional simulation of the North-East Atlantic Ocean (provided by Mercator-Ocean), which includes the tidal signal as well as other oceanic variability which can prevent a proper tide estimation from satellite measurement due to crossed aliasing issues. Results of this tidal desaliasing analysis are presented here.


 

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
Loren Carrere
CLS
France
lcarrere@groupcls.com