first overview of the carols measurements in september 2007earth.esa.int/smos07/pres/22_pres.pdf ·...
TRANSCRIPT
FirstFirst overviewoverview of of thethe CAROLS CAROLS
measurementsmeasurements in in septemberseptember 2007 2007CAROLS: CAROLS: Combined Airborne Radio-instrumentsCombined Airborne Radio-instruments
for Ocean andfor Ocean and!! Land Studies Land Studies
Zribi Mehrez (PI), Hauser Danièle (co-PI), Zribi Mehrez (PI), Hauser Danièle (co-PI), Pardé MickaëlPardé Mickaël, Fanise, FanisePascal, Leroy Paul, Monique Pascal, Leroy Paul, Monique DechambreDechambre
CETPCETP
Boutin Jacqueline, Gilles Reverdin Boutin Jacqueline, Gilles Reverdin LOCEANLOCEAN
WigneronWigneron Jean-Pierre Jean-Pierre INRA - EPHYSEINRA - EPHYSE
Calvet Jean-Christophe Calvet Jean-Christophe Météo - FranceMétéo - France
Nicolas Nicolas ReulReul IFREMERIFREMER
Antonio Antonio RuisRuis BarcelonaBarcelona universityuniversity
Niels Niels SkouSkou
SobjaergSobjaerg Sten Sten SchmidlSchmidl TechnicalTechnical UniversityUniversity of of DenmarkDenmark
andand all CAROLS team all CAROLS team
PresentationPresentation Plan Plan
1 Mission objectives
2 Flight plans / Configuration
3 CAROLS instruments
4 Other instruments on board
5 Ground measurements overview
6 First Results -radiometric measurements
7 Conclusions
1 Mission objectives1 Mission objectives
- Aeronautic certification with ATR-42
-First validation and qualification of the CAROLS radiometer and STORM
radar on board
- Scientific objectives :
Validation of L-Meb model for modeling the ground-vegetation
L-band emission
Development and Validation of ocean emission models
Development and Validation of forest emissivity models
Test of synergy between RADAR (STORM) and passive
measurements (CAROLS)
ObjectivesObjectives
CAROLS CAROLS experimentexperiment
• CAROLS: Cooperative Airborne Radiometer for Ocean and Land
Studies (scientific lead Mehrez ZRIBI)
• STORM: Système de Télédetection pour l’Observation par Radar de la
Mer, (scientific lead Danièle Hauser)
• GOLD-RTR: GPS Open-Loop Differential
Real-Time Receiver, (scientific lead A. Rius)
• Infrared CIMEL radiometer (SAFIRE instrument)
• 1 visible camera (SAFIRE instrument)
CAROLS technical collaborationCAROLS technical collaboration
CETPScientific and technical
Coordination
CAROLS building
STORM instrument
SAFIRE (CNRS/Meteo-France)Instrument/Aircraft interface building
Co-organisation of experimental
Campaigns
Aircraft operations
DTUN. Skou
CAROLS
CSIC/IEEC
GPS instrumentA. Rius
2 Flight plans / Configuration2 Flight plans / Configuration
AircraftAircraft : ATR 42 (SAFIRE) : ATR 42 (SAFIRE)
•• FlyingFlying performance performance
• Max. Cruising speed: 134 m/s
• Ceiling: 25000ft
• Max. endurance: 6h
•• Information for Information for scientificscientific usersusers
• Scientific payload: 2500 kg
• Max range at 4000 km: 3000 km
• Min. altitude: above sea: 100m
• Above ground: 100m
• Speed: 100m/s (min 70m/s max130m/s)
• Seat available for users: 2 experimentoperators, and 7 scientifists
ConfigurationsConfigurations
RadiometerRadiometer (2 (2 antennasantennas))
aircraft
Position of the antenna footprints
RadiometerRadiometer++radarradar
aircraft
Position of the antenna footprints
Flight path and ground measurement sites
1) SmosRex : Météo-France
site
3) Nezer Site : Les Land forest
5) Buscaway gulf (Boat and
drifting buoys)
6) Gascogne buoy
2) SMOSMANIA
4) Hourtin lake
1
2
3
45
6
Airborne measurements
• 24 september (4h30mn) : CAROLS (2 antennas) + GPS
• 25 september (4h30mn) : CAROLS (2 antennas) + GPS
• 27 september (4h30mn) : CAROLS (1 antenna)+ STORM + GPS
• 28 september (4h30mn) : CAROLS (1 antenna)+ STORM + GPS
• 1 october (45mn) : STORM calibration flight
Departure: Francazal military base, 19h30 local hour
Let’s Go !
3 CAROLS3 CAROLS instruments instruments
CAROLS CAROLS radiometerradiometer
built by collaboration CETP-DTU
! Similar to EMIRAD2 for COSMOS2 campaign
! Correlation radiometer with direct sampling
!Fully polarimetric (i.e 4 Stockes)
!Freq : -6 dB @ 1400 MHz 1427 MHZ
- 3 dB @ 1403 MHz 1424 MHZ
! Advanced analog filter for RFI suppression
!Sensitivity : 0.1 K for 1 s integration time (300K target)
!Stability: better than 0.1K over 15 min
!Internal calibration : load and noise diode
!2 large potter horns (HPBW 37,6°)
G=87dB
Tsys= 218K
!T=0,06K
@1s &Tb=100k
AnalogicAnalogic part part
Antenna pattern measurements in CNES
70cm
9,75 kg
80 cm
18,8kg
Nadir Nadir andand slantslant antennaantenna
Slant Antenna
Nadir Antenna
Relative angles to the airplane:
Roll = + 0.33°
Pich = - 0.82°
Heading = 0.22°
Relative angles to the airplane:
Roll = - 33.73°
Pich = -1.5°
Heading = 1.17°
Inside the plane
CAROLS interface CAROLS interface withwith ATR-42 ATR-42
Slant antennaNadir antenna
Antennas outside of the plane
Cables and OMT temperature regulation
Distance between the nadir and the slant antenna : 7m
"Using of cables with very low looses
"5 probes are measuring the cable temperature
during the whole flights
" The OMT’s (orthomode tranducers) are isolated
ReceiverReceiver insideinside thethe plane plane
Receiver
Transcoder
Power distribution unit
Power supply unit
PXI acquisition system
Hard disk SATA
IRIG B generator
CAROLS / AcquisitionCAROLS / Acquisition
CAROLS / InterfaceCAROLS / Interface
Activities performed before the campaign:
• Instrument Characterization, i.e. determination
of Niose Diode characteristics
• External component (RF-cables, OMT, Antennas)
characterization using cryogenic load
Activities performed during the campaign:
• Internal calibration, using the built-in Load and the Niose Diode
• Correction of the internal calibration using the characteristics (S-
parameters) of the external components and knowledge of their
physical temperature (included in the data set).
• Possible end-to-end calibration check when over flying a known
target
Calibration of the radiometerCalibration of the radiometer
CAROLS / CAROLS / InternalInternal calibration calibration
The radiometer delivers a numerical value , function of the noise
temperature presented at the entrance . To determine this temperature, we
have to use the calibration line for each channels (H and V) :
To calibrate each channel, we need two know temperatures to estimate the
gain and the noise radiometer temperature
-Tr 0K 320K 320 K + Tdiode
Tb
V N= GT + Tr
)*( TTRIN
GN +=
N
T IN
G T R
cryogenic
load (80 K)
Before the flights, we measured the attenuation in both cables using a
cryogenic load placed at the end of each cable. The measured attenuation was
around 0.2 dB for the 4.5 m cables.
ReceiverReceiver andand RF RF cablecable calibration calibration
cable
4 Other Instruments on board4 Other Instruments on board
• C-Band (5.6 cm)
• Geometry :
900 m!
X(elevation)x
y
Y (azimuth)!
X(elevation)x
y
z
Y (azimuth)
Look directionLook direction
Incidence range from5 to 35 !
Scan over360 !
– Mean incidence 20°, incidence range 5 to 35°(or more with airplane roll in circle flights)
– Antenna : rotation over 360° (3r/min) or fixedazimuth angle (between 0 and 360°)
– High range resolution (1.53m) => highhorizontal resolution in the elevation direction
STORMSTORM
STORM calibrationSTORM antenna
STORM receiver
STORMSTORM
STORM screenshot
It Captures GPS signals reflected on the Ocean'ssurface to retrieved surface properties(mean level, roughness, etc.)
GOLD-RTRGOLD-RTR
A Ruis
GPS system
GPS receiverAntenna on the ceiling of the plane
5 Ground truth measurements5 Ground truth measurements
Ground parameter measurements
SMOSMANIA: 6 Thetaprobe continuous measurements; West of
Toulouse
(Resp. Jean Christophe Calvet)
Nezer Site: soil moisture measurements
(Resp. Jean Pierre Wigneron)
Hourtin lake: physical temperature measurements
(Resp. J. Boutin and G. Reverdin))
Ocean measurements: buoys, Boat (Cote de la Manche) measurements
(Resp. G. Reverdin and J. Boutin)
- In order to support Airborne CAROLS experiment, a ship campaign was
organized from September 24 to 28, under the airplane track.
- Measurements of sea surface salinity (SSS), sea surface temperature
(SST), wind speed, foam, wave spectrum, heat and momentum flux were
collected on the ship.
- 3 drifters measuring SSS, 12 drifters measuring SST, 1 drifter
performing acoustic wind measurements were deployed.
Ocean measurements
G. Reverdin
J. Boutin, G. Reverdin
In situ SST varies between
18 and 20°C, with a decrease
of ~0.5°C between September
24 and September 28.
Although the campaign took
place in September , a more
than 1 psu gradient was
observed between coastal
and open ocean SSS
During CAROLS flights, wind
speed in the open ocean was
between 7 and 9 m s-1 (as
recorded by Gascogne
meteorological buoy).
CAROLS flights
Strong wind speed
gradient between
coastal and open
ocean observed on
QuikSCAT image on
September 28.
Wind speed
SST
6 First results6 First results
Radiometric measurements Radiometric measurements
Radiometric measurements
Sept 24th Sept 25th
Sept 27th Sept 28th
Tb every 8 ms
Slant antenna
circleswing
wags
First Flightsept 24th 07
Radiometric measurements
Measurements
on Ocean
Measurements
on ground
Hourtin lake
The RFI problemFirst Flightsept 24th 07
Kurtosis = m(4)/m(2)2
Periodic perturbations during the flights
when the aircarft is flying over the soil
Possibility to delete
contaminated data
7 Conclusion and perspectives7 Conclusion and perspectives
For the next months
• Finishing calibration of CAROLS instrument
• Analysis of CAROLS data and RFI
• Preparation of CAROLS flights in october-
November’2008
• Discussion of improvements in CAROLS
instrument
Thank you
To the next flights!
CAROLS / Calibration testsCAROLS / Calibration tests
Measurements on target Measurements on sky
Nadir measurements
Flight AS 0740 Flight AS 0741