NAD Flag: Nadir-Viewing
- Calculate spectra viewing downwards into a plane parallel atmosphere
- *TAN (or *SEC)
section of Driver Table
specifies airmass factor for
calculation (eg, 1.0=vertical, 2.0= 60 deg to vertical)
- Assume limb view (or other geometry)
- SFC Flag must also be enabled.
- Incompatible with
- The plane parallel atmosphere allows several simplifications:
no field-of-view effects, analytical Curtis-Godson path parameters, which
are valid for direct nadir viewing but approximations for slant paths.
For exact downward views in a
spherical atmosphere it is still possible to
use the normal limb-viewing calculation (eg with negative geometric
tangent heights, replacing *TAN
section label with *GEO).
- Use of FLX Flag redefines