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Proceedings Paper

Ensuring that the Sentinel-3A altimeter provides climate-quality data
Author(s): G. D. Quartly; F. Nencioli; S. Labroue; P. Femenias; R. Scharroo; S. Abdalla; P. Bonnefond; M. Cancet; M.-L. Frery; M. Raynal; S. Baker; A. Muir; D. Brockley; A. Shepherd; P. Garcia; M. Roca; S. Calmant; J.-F. Cretaux
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Paper Abstract

Sentinel-3A, launched in February 2016, is part of ESA's long-term commitment to climate monitoring from space. Its suite of instruments for measuring surface topography includes a Microwave Radiometer (MWR) and SRAL, the first delay-Doppler instrument to provide global coverage. SRAL promises fine spatial resolution and reduced noise levels that should together lead to improved performance over all Earth surfaces. The Sentinel-3 Mission Performance Centre (S3MPC) has been developing the methodology to evaluate the accuracy of retrievals, monitor any changes and develop solutions to known problems. The S3MPC monitors internal temperatures, path delays and the shape of the generated pulses to assess the instruments health. The MWR records over known reference surfaces are compared with those from other spaceborne instruments. Over the ocean the SRAL's return pulses are analysed to give range to the sea surface, wave height and signal strength (which can be interpreted as wind speed). The metocean data are regularly contrasted with records from in situ measurements and the output from meteorological models, which rapidly highlights the effects of any changes in processing. Range information is used to give surface elevation, which is assessed in three ways. First, flights over a dedicated radar transponder provide an estimate of path delay to within ~10 mm (r.m.s.). Second, measurements are compared to GPS-levelled surfaces near Corsica and over Lake Issyk-kul. Third, there are consistency checks between ascending and descending passes and with other missions. Further waveform analysis techniques are being developed to improve the retrieval of information over sea-ice, land-ice and inland waters.

Paper Details

Date Published: 3 October 2017
PDF: 16 pages
Proc. SPIE 10422, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017, 104220R (3 October 2017); doi: 10.1117/12.2277593
Show Author Affiliations
G. D. Quartly, Plymouth Marine Lab. (United Kingdom)
F. Nencioli, Plymouth Marine Lab. (United Kingdom)
S. Labroue, Collecte Localisation Satellites (France)
P. Femenias, ESA (Italy)
R. Scharroo, EUMETSAT (Germany)
S. Abdalla, European Ctr. for Medium-Range Weather Forecasts (United Kingdom)
P. Bonnefond, Observatoire de Paris à Meudon (France)
M. Cancet, Noveltis SA (France)
M.-L. Frery, Collecte Localisation Satellites (France)
M. Raynal, Collecte Localisation Satellites (France)
S. Baker, Univ. College London (United Kingdom)
A. Muir, Univ. College London (United Kingdom)
D. Brockley, Univ. College London (United Kingdom)
A. Shepherd, Univ. of Leeds (United Kingdom)
P. Garcia, isardSAT (Spain)
M. Roca, isardSAT (Spain)
S. Calmant, Lab. d'Etudes en Géophysique et Océanographie Spatiales (France)
J.-F. Cretaux, Ctr. National d'Études Spatiales (France)

Published in SPIE Proceedings Vol. 10422:
Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017
Charles R. Bostater Jr.; Stelios P. Mertikas; Xavier Neyt; Sergey Babichenko, Editor(s)

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