IEEE Geoscience and Remote Sensing Magazine - June 2015 - 45

on sea level rise. Data from these satellites are assimilated
along with in situ measurements into ocean-state forecasting models. This assimilation is now operated as a routine
service by the Copernicus Marine Environment Monitoring
Service, provided by Mercator Ocean.
Service continuity will be ensured by the Copernicus
Program with the operations Sentinel-3 and Sentinel-6
(Jason CS) missions: CNES is involved in these programs
through its expertise and technical support to ESA on
performance validation and level 1/2 pre-processing algorithms definition and development.
CNES decided at the end of 2005 to develop the AltiKa
altimetry payload in Ka-band. AltiKa [8] was launched
in 2013 on the Saral satellite jointly designed with ISRO
(Indian Space Research Organisation), the Indian Space
agency. AltiKa supplies higher accuracy measurements
than those of Jason (improvement of the spatial resolution with a smaller footprint of 8km compared to 20km
and sampling with an higher Pulse Repetition Frequency
of 4kHz compared to 2 kHz) enabling a better observation
of ice (Figure 7), coastal areas, continental water bodies as
well as the waves heights.
SWOT (cf II.A.5) will offer a significantly improved kilometric resolution over ocean and will contribute to accurately characterize meso and sub-meso scale circulations
which have a major role in energy transport in oceans.
SWOT will also permit to
characterize coastal circulation effects on marine life,
-30°
ecosystems, water quality,
transports and will improve
modelling of ocean/atmosphere coupling.
3) Sea State: CFOSat
(ChineSe-FrenCh
OCeaniC Satellite)
The Chinese (CNSA: China
National Space Administration) and French (CNES)
Space Agencies are jointly
developing the CFOSAT mission (Chinese-French Oceanic SATellite) scheduled
for launch in 2018 [9]. This
mission will focus on monitoring of ocean surface wind
and waves. Wind/waves observations will be supplied
in near-real time to the meteorological agencies in order to improve their forecast
and the sea state models.
These measurements will
also be provided to the scientific community for oceanojune 2015

graphic and climate research to improve the sea models as
well as the understanding of the influence of sea state in
surface fluxes.
CFOSAT will carry two main instruments: a wave-scatterometer spectrometer (SWIM: Surface Waves Investigation
and Monitoring) supplied by CNES, and a scatterometer
(SCAT) supplied by CNSA to measure ocean winds.
SWIM is a real aperture radar system at Ku-band
(13.575 GHz), pointing at incidence angles between 0 and
10° (multi-incidence beams) with a beam scanning and in
azimuth (0-360°). The observations at nadir will be used
in a way similar to other radar altimeters (ERS-2, TOPEXPOSEIDON, Jason) for estimating wind speed and significant wave height. The off-nadir looking observations are
defined to fulfill the objective of measuring the directional
ocean wave spectra, and the statistics of wave slopes.
C. ATMOSPHERE OBSERVATORIES
1) iaSi FOr mOre aCCurate weather FOreCaStS
IASI (Infrared Atmospheric Sounding Interferometer) is
one of the instruments flown on board the METOP meteorological satellites. IASI has been developed in cooperation
between Eumetsat, in charge of the overall system and the
procurement of the recurrent units and CNES, in charge of
the instrument design and development.

30°

90°

-90°

150°

-150°

-500

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m

2000

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3500

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Figure 7. Map of Altika Ice sheet topography derived from Altika in 2013 (F. Rémy, D. Blumstein, A.

Michel, T. Flament, LEGOS, Toulouse).

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Table of Contents for the Digital Edition of IEEE Geoscience and Remote Sensing Magazine - June 2015