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)
- Used in combination with
FLX flag, can specify upwards fluxes,
or transmittance from each level to surface.
- 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.
- It is also possible to define a nadir view with the full spherical
atmosphere calculations, replacing *TAN
section label with *ELE and setting an elevation angle -90.
- Use of FLX Flag redefines