Data Processing Analysis and Improved Altimetric Parameter Estimation over ocean, land areas and ice regions

Author:

Thomas Moreau - (CLS)

Co-Investigator(s):

Laiba Amarouche (CLS)
Jérémie Aublanc (CLS)
François Boy (CNES)
Jean-Alexis Daguze (CLS)
Salvatore Dinardo (CLS)
Sébastien Figerou (CLS)
Sophie Legac (CNES)
Claire Maraldi (CNES)
Nicolas Picot (CNES)
Fanny Piras (CLS)
Pierre Thibaut (CLS)
Ngan Tran (CLS)
Stéphanie Urien (CLS)

Abstract:

The proposed studies aim at contributing to the various objectives of the Joint Research Announcement “Ocean Surface Topography Science Team” through the assessment and the improvement of the altimeter parameter estimation, in line with the work performed for many years by the processing expert team in CLS with most altimetry missions: TOPEX/POSEIDON, Jason-1, Jason-2, Jason-3, ENVISAT/RA-2, HY-2, Cryosat-2, Saral and Sentinel-3. Our support to the OSTST will consist in two main activities:

• Development and assessment of enhanced level-1 and level-2 algorithms and/or models/corrections likely to improve the quality of the data over open ocean and particular zones: coastal oceans, inland waters (and, to a lesser extent, ice surfaces which will be rarely or very partially overflown). For open ocean, attention will be specifically drawn to the phenomena that depart from the "nominal" oceanic conditions: rain cells, sigma blooms, internal waves etc ..., but also to long ocean waves and wave motion that may impact the performances of the delay-doppler altimeter system. Both conventional and delay doppler altimetry processing will be considered in these activities.
• Scientific application studies: mesoscale observability and variability, ocean currents, coastal altimetry, continental water monitoring (and, to a lesser extent, polar oceans observations and sea-ice studies)

The proposed work is organized around 4 themes all dealing with a state-of-the-art analysis of the altimeter backscattered signals, processing systems (including level-1 up to level-2 algorithms) and parameters derived from them, and all taking advantages of the high-level expertise of our team:

• Theme 1: Development of optimal algorithms (level-1 and 2 processing, and corrections) depending on the altimeter acquisition mode and over-flown surfaces.
• Theme 2: Computation of mission performances, comparison with other missions, and recommendation for future missions.
• Theme 3: Derivation/assessment of the Sea State Bias (SSB): non parametric methods and the new methods currently developed at CLS.
• Theme 4: Analysis of the instrument behavior along the orbit and ageing with time and impact on the estimation of the long term climate trends.

Supported by CNES.