The CFOSAT project: a cooperation
to assess wave directional spectra
and surface winds
P.Castillan(1), N. Corcoral(1), C. Tison(1),
T. Amiot(1), E. Thouvenot(1), D. Hauser(2)
(1) CNES,
« Altimetry and Radar » department,
France
(2) OVSQ, CNRS, LATMOS-IPSL, France
Patrick.castillan@cnes.fr
China
France
Oceanography
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Summary
►What
is the CFOSAT mission?
►Mission
objectives
►Description
►Focus
of CFOSAT
on the SWIM instrument
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The CFOSAT mission
SWIM
SCAT
►CFOSAT:
an innovative China/France mission for oceanography
►Joint measurements of oceanic wind and waves
SWIM: a wave scatterometer (new instrument)
SCAT: a wind scatterometer (fan beam concept)
This mission is a “world première”
►SWIM,
new spaceborne instrument with technology innovations
(antenna, on-board digital processing)
►SCAT, new concept of wind scatterometer
►Access to 2D wave spectrum with high angular resolution and with
global scale
►Joint measurements of winds and waves
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The CFOSAT mission
►CFOSAT
►CFOSAT
is:
a scientific mission for public services
(Meteorology agencies, research
centers, marine agencies, etc.)
a demonstration and pre-operational
mission (for Météo France, EUMETSAT,
CEPMMT, etc.)
adds:
a new component to spatial oceanography
systems
assimilation of CFOSAT data in
meteorological models
possible integration of CFOSAT wave
measures in GMES/MyOcean, GlobWave.
Spatial
observations
Models
Forecast
In situ
observations
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Key dates
2006
►Signature of the Memorandum Of Understanding
CFOSAT
2007- 2008
►Phase A CFOSAT
Feasibility demonstration
2009-2010
►Phase B CFOSAT
Preliminary design
2011-2014
►Phases C/D CFOSAT
Detailed design
Manufacturing of flight model and qualification
models
2015
►Operational system in orbit
Launch from China (end of 2014)
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A China/France cooperation
Principal Investigators
D.Hauser – CNRS/LATMOS
Liu Jianqiang - NSOAS
Launch / campaign
CFOSAT system – science & data
Satellite
Satellite control
Platform
Stations
CNSA/DFH
CNSA
SWIM
CNES
Contract : Thales Alenia Space
Operations / Mission
X-band stations
CNSA/NSOAS
Control center
CNSA
Chinese mission center
CHOGS
CNSA/NSOAS
SCAT
CNSA/CAS (CSSAR)
Polar X-band stations
Network
CNES
Contract : SSC
CNSA
X-band TM
CNSA/CNES
Contract : Thales Alenia Space
Operations
CNSA
French mission center
FROGS
CNES/IFREMER
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Scientific objectives
►Global
observation of ocean wind and waves with high temporal coverage
►Why?
To improve wind and wave forecast and sea-state monitoring
To improve the knowledge and the modeling of sea-surface processes
To get a simultaneous wind and wave measures for coupling effects characterization
Waves generation by
local winds
Free propagation
(swell)
Bathymetry impact
Coastal wave breaking
►Secondary
objectives (for SWIM)
Land surface monitoring (soil moisture and soil roughness)
Polar ice sheet characteristics
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CFOSAT goals
►Sea
state conditions have great impact on:
Commercial activities: marine transport and offshore
activity (oil platform)
Pollution transport
Security at sea and in coastal areas
Biology and sediment transport
Sea-ice formation/destruction
Gas exchange (CO2), stress over the ocean, heat
fluxes
Sea color (Albedo)
►Wind
and waves measures are mandatory for weather forecast and climate survey.
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Scientific requirements
►Mission
Minimum duration of 3 years
Global coverage over the oceans (polar orbit)
Data available in near-real time
►SWIM
Directional wave spectra from incidences 6° to
8°
To be measured in the wavelength range 70m-500m
With a 10% accuracy on wavelength, 15° accuracy
on wave propagation direction
With a 15% accuracy on spectral level around the
peak of the spectrum
Significant wave height and wind speed from
nadir
10% on SWH (or 50 cm whichever is better)
rms <2 m/s on wind speed
Normalized radar cross-section form 0 to 10°
Absolute accurcay of ±1 dB
Relative accuracy between incidences ± 0.1 dB
►SCAT
Wind vector
Wind speed range and precision: 2m/s or 10%
(larger) @5~24m/s
Wind direction precision: 20 °
Backscattering coefficient precision : 0.5dB
Surface resolution
50km (standard product)
25km(experimental product)
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Payloads
►Two
scientific payloads
SWIM: Surface Waves Investigation and Monitoring
SCAT: wind SCATterometer
►SWIM
Surface Waves Investigation and Monitoring
Real aperture radar in Ku-band
6 incidence angles: 0°, 2°, 4°, 6°, 8° et 10°
Antenna diameter: 90 cm (~2° aperture)
Polarization VV
Rotation speed: 5.7 rpm
Power: 120 W
Useful bandwidth: 320MHz
Pulse duration: 50 µs
PRF: 2 - 7 kHz
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Payloads
►Two
scientific payloads
SWIM: Surface Waves Investigation and Monitoring
SCAT: wind SCATterometer
Rotating fan beam antenna
►SCAT
Flig
h
Wind SCATterometer
Real aperture radar in Ku-band
t di
rec
tion
Nadir point
Fan beam concept
Incidence angles (on ground): 20°-65°
Surface footprint
ath
Sw
Antenna size: 1.2mx0.4m
Alternate polarization: HH-VV
Rotation speed: 3.2 rpm
Power: 120 W
Useful bandwidth: 0.5 MHz
© CSSAR/CAS
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Satellite
►Orbit
Sun synchronous
Local time at descending node
AM 7:00
Altitude at the equator
519 km
Cycle duration
13 days
►Mass
and dimensions
Mass
~600 kg
Primary structure
~1.5mx1.5mx1.5m
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CFOSAT Movie
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Ground system
Inuvik
Kiruna
Mudanjiang
IWWOC –
Waves & Wind
Mission Center
Brest
CWWIC
Instruments Mission
Center
Toulouse
Control center
S-band network
Xi’an
Beijing
Sanya
Chinese Mission Center
Beijing
Users
Worldwide
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