Dependence of Brightness Temperature on Bistatic Scattering With Applications to Antarctica

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Dependence of Brightness Temperature on Bistatic
Scattering With Applications to Antarctica

• Christian Mätzler (University of Bern,
  Switzerland),
• email matzler_at_iap.unibe.ch,
• and Philip W. Rosenkranz (MIT, USA)

MICRORAD06, San Juan, Puerto Rico, March 2006
ITWG Workshop, Paris, June 2006
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Surface scattering is described by the Bistatic
Scattering Function S of Chandrasekhar
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In the reciprocal situation S describes the
transfer fromincident sky radiation to the
scattered radiation in the observation direction
Reflectivity r and emissivity e
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Some analytic scattering functions and
reflectivities (with azimuthal independence)
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Transmissivities for
given S functions
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where
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Effective transmissivity and incidence angle
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Polar summer atmosphere with IWV2kg/m2
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A parameter to characterize the actual scatter
behavior the Lambertivity AL
We determined AL together with water vapor,
temperature and surface emissivity spectra (24,
31, 50, 53, 89 GHz) from AMSU-A data of the Aqua
Satellite (incidence angles 0 to 56). For AL
a-priori value 1, limitation to incidence angle
lt 30, emphasis on 50 - 53 GHz. Solution found
by minimizing a cost function by Newtonian
iteration (Rodgers 1976, Eyre 1989).
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AL gt 1 for the models of Peake and
Lommel-Seeliger (?0.35 and ?0.55). AL1 for
pure Lambert scattering.
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Conclusions
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References C. Mätzler, "On the determination of
surface emissivity from satellite observations",
IEEE Geoscience and Remote Sensing Letters, Vol.
2, No. 2, pp. 160-163 (2005). W.H. Peake,
"Interaction of electromagnetc waves with some
natural surfaces", IRE Trans. Antennas and
Proppagation, AP-7, Supplement p. S324-S329
(1959). C.D. Rodgers, Retrieval of atmospheric
temperature and composition from remote
measurements of thermal radiation, Rev.
Geophys. and Space Phys., 14, pp. 609-624,
1976. P. W. Rosenkranz, Retrieval of temperature
and moisture profiles from AMSU-A and AMSU-B
measurements, IEEE Trans. Geosci. and Remote
Sensing, 39, 2429-2435, 2001. P. W. Rosenkranz,
"Rapid radiative transfer model for AMSU/HSB
channels," IEEE Trans. Geosci. and Remote
Sensing, 41, 362-368, 2003. P. W. Rosenkranz, "
Cloud liquid-water profile retrieval algorithm
and validation," J. Geophys. Res.,
doi10.1029/2005JD005832, in press 2006. P. W.
Rosenkranz and C. D. Barnet, "Microwave radiative
transfer model validation," J. Geophys. Res.,
doi10.1029/2005JD006008, in press 2006. F.T.
Ulaby, R. Moore, and A.K. Fung "Microwave Remote
Sensing, Active and Passive", Vol. I,
Microwave Remote Sensing Fundamentals and
Radiometry", London (1981), Vol. II, Radar Remote
Sensing and Surface Scattering and Emission
Theory (1982) Vol. III, From Theory to
Applications, Artech House Inc., Norwood, MA
02062 (1986). The following view graphs are
complementary
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Frequencies and Opacities of AMSU Channels
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Exponential Integrals
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The a parameter versus single-scat. albedo