Last TUGO model simulations and perspectives of evolution of the Dynamic Atmospheric Correction for altimetry

Loren Carrere (CLS, France)

CoAuthors

Damien Allain (CLS/LEGOS, France); Florent Lyard (LEGOS, France); Yannice Faugere (cls, 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

Given its current accuracy and maturity, altimetry is considered a fully operational observing system dedicated to various applications such as operational oceanography and climate studies. Altimeter measurements are corrected for several geophysical effects in order to isolate the oceanic variability, and the Dynamic Atmospheric Correction (DAC) is the second most important one after the tide correction. This DAC correction allows for the removal of high frequency ocean variability induced by the atmospheric forcing and aliased by the altimetric measurements.
The accuracy of the DAC has been much improved over the last 25 years leading to centimetric accuracy in open ocean. However significant errors still remain mainly in shallow waters and in polar regions, due to bathymetric errors, to atmospheric forcing errors, to local lack of resolution of the grid, or even to sea ice effects ...
In this context and taking into account the new challenges of dynamic atmospheric correction for the coming high-resolution altimetry missions, several ways of improvements are being tested, including: replacing the barotropic model MOG2D by TUGO-M version, using higher frequency temporal sampling provided by the new ERA-5 ECMWF meteorological database, using a higher resolution mesh, or generating higher frequency maps of DAC to take into account a better propagation of the high frequency surge signal. Including the gravitational tide forcing within the barotropic model used to compute the DAC is also investigated to try to improve the bottom friction dissipation in the simulations. Preliminary results are interesting and show significant improvement in some regions of interest. We will describe the tests performed and some validation results and we will present an implementation plan for a new version of the operational DAC for altimetry in 2020.

 

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