Hello Randy,
Sorry for the slow reply. This variable has been used in CMIP5 and TAMIP
to produce model diagnostics comparable to satellite measurements.
The data produced include the cos(SZA) factor, but not the integration
over the solid angle.
Regards,
Alejandro
________________________________
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On
Behalf Of Randy Horne
Sent: Tuesday, June 26, 2012 11:45 PM
To: cf-satellite at unidata.ucar.edu; cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] standard name question
-"toa_bidirectional_reflectance"
Folks:
I am working the GOES-R program. We have a few very specific
questions on the use of a standard name (toa_bidirectional_reflectance):
The top of atmosphere (TOA) reflectance is a key product from
satellite observations but is
often ambiguous as a result of the many non-standard definitions
used throughout the
community. The CF standard name table includes
"toa_bidirectional_reflectance" as a unitless
quantity that is the ratio of the reflected to incident energy.
However, the details of this
quantity are not completely clear.
(1)
Does it include an integration of solid angle - i.e.,
introducing a factor of PI for Lambertian surface? Does it include or
exclude the cosine (SZA) factor that is often omitted from imagery (and
that allows a direct scaling from radiance to
reflectance)?
(2) What programs have already adopted the
"toa_bidirectional_reflectance" and how can one ensure that the
convention is being used consistently with respect to the above
questions?
very respectfully,
randy
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