Performances and assessment of Cryosat-2 and Sentinel-3A SARM over ocean inferred from existing ground processing chains.

Matthias Raynal (CLS, France)

CoAuthors

Sylvie Labroue (CLS, France); Stéphanie Urien (CLS, FRANCE); Laiba Amarouche (CLS, FRANCE); Thomas Moreau (CLS, FRANCE); François Boy (CNES, FRANCE); Pierre Féménias (ESA, ITALY); Jérôme Bouffard (ESA, ITALY)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Regional and Global CAL/VAL for Assembling a Climate Data Record

Presentation type: Type Poster

The ESA (European Space Agency) mission Cryosat-2, launched in 2010, differs from previous altimetry missions as it has been designed to monitor the fluctuations of the thickness of land and marine ice fields (Wingham et al., 2006). To enhance the measurement resolution and precision over these surfaces, the on board altimeter SIRAL is based on a different principle proposed by Raney (1998): the Synthetic Aperture Radar mode (SARM) also referred to as Delay Doppler Mode. Although Cryosat-2 mission is dedicated to the cryosphere observation and was initially designed for this purpose, the altimeter also provides measurements over ocean. The altimetry community exploited this opportunity to process and analyse these new measurements. SARM datasets analyses presented in 2012 and 2013 during the OSTST meetings, demonstrated the potential of this technique to retrieve finest ocean scale signals. These results turned out as a recommendation from the user community to have a full SARM coverage as baseline for Sentinel-3A altimeter.

Sentinel-3A mission was successfully launched in February 2016. It is a multi-instrument mission to measure surface topography, sea- and land-surface temperature, ocean colour and land colour with high-end accuracy and reliability. The SRAL (Sentinel Radar Altimeter) altimeter on board Sentinel-3A and inherited from Cryosat-2 altimeter, operates in SARM full coverage since the 12th of April 2016.

Today with these two SARM altimeters flying, the years of experience acquired in SARM processing and the increasing number of SARM datasets derived from different processing, how confident the user community can be in the use of Delay Doppler altimetry products? Based on the assessment of several SARM datasets derived from different processing chains (ESA Cryosat-2 Ocean Baseline C and Sentinel-3a ground segment, CNES Cryosat-2 and Sentinel-3a processing prototypes) this paper aims at giving an overview of the similarities and the main discrepancies that remain between all these datasets. It will demonstrate that the SARM expected benefits are effectively observed through different SARM processing. It will describe how close the estimated geophysical parameters are even if derived from different processing on both missions.

 

Poster show times:

RoomStart DateEnd Date
Concerto Ballroom Thu, Oct 26 2017,14:00 Thu, Oct 26 2017,18:00
Matthias Raynal
CLS
France
mraynal@cls.fr