*ALT, *PRE or *TAN Section

08SEP24
Type
Primary Section#4

Description
Retrieval/Forward Model grid levels
The section label defines the grid type
Label Grid
*ALT Altitude grid
*PRE Pressure grid
*TAN Tangent Height grid [2]

Format
Single field
Field Type Description
GRDFIL C200 Name of .atm File
* C1 Use default grid[3]
Type: Cn=character string, length n.

Notes
  1. The appropriate profile is extracted from an .atm format file, (with *HGT used for either Altitude or Tangent Height). Typically this would be a specific file containing just the grid levels. This defines NLEV, the number of grid levels.

  2. The Tangent Height grid is the set of nominal tangent heights for limb-viewing spectra, which should be a sub-set of those in the L1C spectra, plus extra altitude levels for the forward model.

  3. See subroutine LEVDEF for default grids for *ALT and *PRE For *TAN the default grid is the nominal tangent heights in the L1C file, plus one extra level below the minimum (to allow for FOV convolution) and levels above in 10km steps.