1. L-BAND R ADIOMETRIC M EASUREMENTS IN THE
G ULF OF B ISCAY: SMOS AND CAROLS
A. Martin1 , J. Boutin1 , D. Hauser2 , G. Reverdin1 , M. Pardé2 ,
M. Zribi2,3 , P. Fanise2,3 , X. Yin1 , J. Tenerelli6 , N. Reul5
1 LOCEAN-IPSL, Paris
2 LATMOS-IPSL, Paris
3 CESBIO, Toulouse
5 IFREMER, Plouzané
6 CLS, Plouzané
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 1 / 25

2. O BJECTIVES
CAROLS — VALIDATION FOR SMOS
ATR42 - SAFIRE
Synergy between passive & active
microwave data
Comparison of SMOS and
SMOS CAROLS data in the Gulf of
Biscay
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 2 / 25

3. SMOS AND CAROLS F LIGHT T RACK
A IRBORNE C AMPAIGN N OVEMBER 2010
19 Nov. asc.
22 Nov. des.
25 Nov. des.
27 Nov. asc.
ACQUISITION T IME :
25 N OV.
CAROLS: 18 to 23 UTC
SMOS: 18:45 UTC
November 25, 2010 — Gulf of Biscay
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 3 / 25

4. SMOS AND CAROLS F LIGHT T RACK
A IRBORNE C AMPAIGN N OVEMBER 2010
19 Nov. asc.
22 Nov. des.
25 Nov. des.
27 Nov. asc.
ACQUISITION T IME :
25 N OV.
CAROLS: 18 to 23 UTC
SMOS: 18:45 UTC
November 25, 2010 — Gulf of Biscay
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 3 / 25

5. O UTLINE
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 4 / 25

6. O UTLINES
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 5 / 25

7. A IRBORNE I NSTRUMENTS
CAROLS L-band (21cm) radiometer
STORM C-band (5.6cm) scatterometer
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 6 / 25

8. CAROLS
CAROLS Radiometer (derived from EMIRAD 2)
[Zribi et al., 2011]
Correlation radiometer with direct sampling
Fully polarimetric (i.e 4 Stockes)
Freq : - 3 dB @ 1401 MHz 1426 MHZ
Sensitivity : 0.1 K for 1 s integration time CAROLS Antenna
(300K target)
Stability: better than 0.1K over 15 min
Internal calibration : load and noise diode
A large potter horn (HPBW 37.6◦ ) at 34◦
Cables with low loss and well monitored
temperature
CAROLS OMT
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 7 / 25

9. CAROLS
G ULF OF B ISCAY — 25 N OVEMBER 2010
Tb P ROCESSED AT LATMOS
correction for cable attenuation and reflexion
sorting out RFI (kurtosis method)
T HIS W ORK
Tb averaged on 1s
keep incidence angles ∈ [33.3o ; 34.3o ]
then averaged on ≈2 min centered on
STORM measurements
use V and H polarizations
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 8 / 25

10. STORM — C- BAND S CATTEROMETER
high wind speed
low wind speed
C-band radar (5.6 cm)
antenna rotation (360˚/min)
incidence range 5 to 35◦ σ 0 vs. incidence angle
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 9 / 25

11. O UTLINES
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 10 / 25

12. G EOPHYSICAL C ONDITIONS
in situ SSS STORM deduced Wind CAROLS L-band
Speed (VV at 30◦ ) Brightness Temperature
H-pol
SST = 12-15˚C
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 11 / 25

13. O UTLINES
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 12 / 25

14. B RIGHTNESS T EMPERATURES S IMULATIONS
TRAP: T ERRESTRIAL R ADIOMETRY A NALYSIS PACKAGE SOFWARE
M ODELING L- BAND R ADIOMETER S IGNAL
Sea Surface Emissivity
for a flat surface [Klein and Swift, 1977]
contribution of Roughness (two-scale model) [Dinnat et al., 2003]
Atmospheric Emissivity and Absorption [Liebe et al., 1993]
Modeling of SMOS Tbs
Scattering of sky radiation by Sea Surface [Tenerelli et al., 2008]
• Tb = Tbatm! + Rsea (Tbatm" + Tbsky) exp(-τatm) + Tbsea exp(-τatm)
M ODELING CAROLS A NTENNA
T EMPERATURE
Atmosphere CAROLS antenna lobes
geometry
aircraft attitude
Tbsea= (Tbflat+Tbrough) (1-F) + F Tbfoam
Tbsea=esea SST
5 m/s ≈ 1K
Ocean
esea derived from SMOS Tbs after correcting for all other effects
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 13 / 25

15. B RIGHTNESS T EMPERATURES S IMULATIONS
TRAP: T ERRESTRIAL R ADIOMETRY A NALYSIS PACKAGE SOFWARE
M ODELING L- BAND R ADIOMETER S IGNAL
Sea Surface Emissivity
for a flat surface [Klein and Swift, 1977]
contribution of Roughness (two-scale model) [Dinnat et al., 2003]
Atmospheric Emissivity and Absorption [Liebe et al., 1993]
Modeling of SMOS Tbs
Scattering of sky radiation by Sea Surface [Tenerelli et al., 2008]
• Tb = Tbatm! + Rsea (Tbatm" + Tbsky) exp(-τatm) + Tbsea exp(-τatm)
M ODELING CAROLS A NTENNA
T EMPERATURE
Atmosphere CAROLS antenna lobes
geometry
aircraft attitude
Tbsea= (Tbflat+Tbrough) (1-F) + F Tbfoam
Tbsea=esea SST
5 m/s ≈ 1K
Ocean
esea derived from SMOS Tbs after correcting for all other effects
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 13 / 25

16. B RIGHTNESS T EMPERATURE D EPENDENCE ON W IND
Measure Tb (V and H-polarization) vs. Wind Speed
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 14 / 25

17. B RIGHTNESS T EMPERATURE D EPENDENCE ON W IND
Time biases on Tb around 0.5K
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 15 / 25

18. B RIGHTNESS T EMPERATURE D EPENDENCE ON W IND
S CATTERED G ALACTIC N OISE ALONG THE FLIGHT
Modeled Scattered Galactic Noise
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 16 / 25

19. B RIGHTNESS T EMPERATURE D EPENDENCE ON W IND
S CATTERED G ALACTIC N OISE D EPENDENCY
Scattered Galactic Noise Dependency
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 17 / 25

20. B RIGHTNESS T EMPERATURE D EPENDENCE ON W IND
A FTER REMOVING ALL MODELED DEPENDENCY
δTb = Tbmeasured − Tbmodeled (WS = 5ms−1 )
δTb vs. Wind Speed
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 18 / 25

21. O UTLINES
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 19 / 25

22. SMOS DATA
Last L1 (Roger Oliva pers. L2 RFI flags equal to 1 if:
com.) and L2 processing
2 2
σrad + σmod
(v500) std(Tbmeas−OTT − Tbmod ) > 1.2
N
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 20 / 25

23. O UTLINES
1 A IRBORNE ACQUISITION
Airborne Instruments
Geophysical conditions
L-band Brigthness Temperature
2 SMOS
Retrieved SSS
Tb Analysis
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 21 / 25

24. SMOS S NAPSHOT
AFFOV & EAFFOV H in the satellite frame V in the satellite frame
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 22 / 25

25. SMOS S NAPSHOT
AFFOV & EAFFOV H in the satellite frame V in the satellite frame
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 22 / 25

26. SMOS — T B A NALYSIS
EAFFOV EAFFOV
Southest Block Northest Block
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 23 / 25

27. C ONCLUSIONS & P ERSPECTIVE
C ONCLUSIONS
High correlation between Brightness Temperature and
scatterometer Wind Speed;
SMOS data, highly polluted by RFI in the Gulf of Biscay for
descending orbit.
P ERSPECTIVE
Analysis other flights of the November 2010 campaign;
Looking at the ascending orbite in the Gulf of Biscay;
Study the influence of Land contamination;
Further validate the galactic scattering model using other
CAROLS flights.
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 24 / 25

28. Thanks for your attention

29. Dinnat, E., Boutin, J., Caudal, G., and Etcheto, J. (2003).
Issues concerning the sea emissivity modeling at L band for
retrieving surface salinity.
Radio Science, 38(4):8060.
Klein, L. and Swift, C. (1977).
An improved model for the dielectric constant of sea water at
microwave frequencies.
IEEE Journal of Oceanic Engineering, 2(1):104–111.
Liebe, H., Hufford, G., and Cotton, M. (1993).
Propagation modeling of moist air and suspended water/ice
particles at frequencies below 1000 GHz.
In AGARD, Atmospheric Propagation Effects Through Natural and
Man-Made Obscurants for Visible to MM-Wave Radiation.
(SEE N94-30495 08-32).
Tenerelli, J., Reul, N., Mouche, A., and Chapron, B. (2008).
Earth-viewing L-band radiometer sensing of sea surface scattered
celestial sky radiation-Part I: General characteristics.
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 25 / 25

30. IEEE Transactions on Geoscience and Remote Sensing,
46(3):659–674.
Zribi, M., Parde, M., Boutin, J., Fanise, P., Hauser, D., Dechambre,
M., Kerr, Y., Leduc-Leballeur, M., Reverdin, G., Skou, N., et al.
(2011).
CAROLS: A New Airborne L-Band Radiometer for Ocean Surface
and Land Observations.
Sensors, 11:719–742.
Adrien MARTIN (LOCEAN-IPSL) SMOS & CAROLS IGARSS Vancouver 2011 25 / 25