*ELE Section

RFM Driver Table Sections: Ray Path
16JUL24
Type
Primary Section#6
Alternative to *TAN section.

Description
Define viewing direction by Elevation Angle [deg] at the observer location (+ve is above local horizontal)
This requires observer altitude to be specified (OBS flag, *OBS section), and can be used with either circular or plane-parallel geometries.

Format
Multiple fields, any order
Field Type Description Units Range
ELE R Elevation angle deg ±90[1]
ELEFIL C200 Name of a Data File [2]
Type: R=Real; Cn=character string, length n.

Notes
  1. ELE: With the plane-parallel atmosphere (ZEN or NAD flags) there is also a minimum absolute value to avoid infinite length paths. This currently set to 0.1 deg, equivalent to 600 airmasses, set by (ELEMIN in chknad_sub.f90

  2. ELEFIL The type of field is identified by first using the Fortran INQUIRE statement to see if it is a file (assumed to be a .dat file), in which case the file is opened and the numbers read from the file as if they were directly inserted within the section at that point. This can be used in combination with actual numerical fields.

Examples
Set of elevation angles for a balloon observations, circular geometry
*ELE -90, -1.5, -0.5, 0.0, 0.5, 1.5 ! [deg] nadir, plus views towards limb

Bugs
Bug#48 (Fixed v5.21)