*SFC Section | ||
RFM Driver Table Sections: Surface Description | 08MAY24 |
Since RFM v5.10, the
TRA,
ABS and
OPT output spectra
only refer to the direct path
atmospheric component (and are therefore the same
as would be obtained using the
ZEN flag).
This only applies to the
downward paths using the plane-parallel atmosphere
(NAD flag).
Limb paths are treated as usual so will have zero transmittance if fully
intersecting the surface. This is to ensure that paths which partially
intersect the surface (i.e., with
FOV convolution) are treated consistently.
The radiance outputs, i.e.
RAD,
BBT and
RJT output spectra, always include the surface
emission and any reflected atmospheric emission as would be expected.
To test whether EMSSFC is a value or a filename,
the RFM first attempts
to open it as a file. If this fails, a value is assumed. Consequently any
fatal error message arising from an incorrect filename/path could be misleading.
Example of a regularly gridded emissivity data file (eg data.sfc from above) in RFM Spectral File Format for regularly gridded data*SFC TEMREL=0.0 ! Equivalent to default value EMSSFC=data.sfc HGTSFC=2.0 ! Set surface at 2km altitude
The same data could be represented as an 'irregularly' gridded file! Surface emissivity spectrum !N.Pts WNO1 WNOD WNO2 5 800.0 50.0 1000.0 0.995 0.996 0.995 0.994 0.993
! Surface emissivity spectrum !N.Pts WNO1 WNOD WNO2 5 800.0 0.0 1000.0 800.0 0.995 850.0 0.996 900.0 0.995 950.0 0.994 1000.0 0.993