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