RFM Driver Table Sections

*LEV Section: Intermediate Output Levels

05SEP05
Type
Secondary Section - depends on LEV Flag.

Description
Specify altitudes for intermediate output levels along the ray path

Format
Multiple fields, arbitrary order.
FieldTypeDescriptionRange
ALT R*4 Altitude [km] of output level Within altitude range specified in *ATM section
FILALT C*80 Name of .tan file containing ALT values
Notes
  1. This section will create additional output spectra representing the integrated paths from the remote side of the atmosphere towards the observer. Effectively this is the same as specifying multiple observer altitudes (OBS Flag) along the ray-path within the same driver table.
  2. If the output levels do not correspond to existing atmospheric levels, extra levels will be inserted
  3. For limb-viewing paths and nadir paths with surface reflection there will generally be two output spectra calculated for each specified altitude: one corresponding to the downward integration from the top of the atmosphere to the tangent point or surface, the other corresponding to the upward integration to the observer.
  4. Output spectra are created as normal spectral files with the level information following the [s][t] information in the output filename, e.g. if the tangent point is 8km and an output level at 11km is selected, then in addition to a normal radiance file rad_a08000.asc there will be two additional spectra rad_a08000_down11000.asc (corresponding to an observer at 11km viewing downwards to a tangent point at 8km) and rad_a08000_up11000.asc (corresponding an observer at 11km viewing upwards).
  5. No output files are generated for levels which are not intersected by the ray path (eg specifying an output level at 14km when the tangent point is at 15km) or for which the contribution is identically zero (eg downward integration for a nadir view with non-reflective surface)

Example 
*LEV
    11 12 13      ! outputs at 11, 12 and 13 km
    alts.lev      ! and further altitudes contained in file alts.lev

Bugs
[none reported]