*GEO Section | ||
RFM Driver Table Sections: Ray Path | 26JUL24 |
Field | Type | Description | Units | Range
R
| Geometric tangent height
| km
| −RadCrv : TOA[1]
| | C200
| Name of a Data File
[1]
| |
---|
Expanding ρ= vp/(RT),
at temperature T=296 K and standard atmospheric pressure p,
assuming a volume mixing ratio of v=1 ppmv (keep the concentration
low to return air-broadened k rather than self-broadened)
General Comments
While such paths, by definition, cannot intersect the surface, if
FOV convolution is included (FOV Flag) it is
is possible that some of the additional ray paths will intersect
the surface, in which case
Extra profile levels will be interpolated for any specified
HGT
values which are not existing internal height profile levels.
For radiative (rather than the usual transmittance)
calculations for a homogeneous path,
the SFC Flag may be used to set
'backplate' conditions.
Otherwise it is assumed
(effectively) that the far end of the path is a black body at zero Kelvin.
χ
= k ρ s
where ρ is the absorber density and s is the path length.
The aim is to set ρs =1
mole/m2,
so that, numerically, χ=k.
s = (1 mole m-2 ) ( R T )/( v p )
= (1 mole m-2 )
( 8.3145 J mole-1 K-1 × 296 K)
/ ( 10-6 × 1013.25 Pa )
= 2.4289 × 106 m = 2428.9 km
*TAN paths.tan ! list of tangent heights from a standard scan pattern. 40 41 42 ! additional paths at 40, 41, 42 km,
*SEC 1 ! Direct nadir view only
*ELE -90, -1.5, -0.5, 0.0, 0.5, 1.5 ! [deg] nadir, plus views towards limb
*LEN UNITS=cm 50.3 ! Output filenames will be, eg tra_50300.asc