*MIC Section

06JUL25
Type
Mandatory Section#6

Description
List of microwindows or spectral filters to be used, and absorbing species to be considered (in addition to retrieved species, which are assumed to be absorbers in every microwindow)

Structure
The format is different according to whether limb or nadir-viewing geometry is selected, and if spectral filters are used rather than microwindows.

The section can either contain the microwindow information directly, or the names of files with the same data structure, or a combination of the two.

MORSE processes the microwindows sequentially in the order in which they appear in this section. In theory the end result should not be sensitive to the order in which microwindows are used but in practice there are always small differences due to convergence, etc.
Filenames (Nadir or Limb)
MICFIL Name of Microwindow File
Nadir-Viewing
MICLAB WNOMIN WNOMAX NABS [NCHN] Rec#1: Microwindow Header
ABS(1) ABS(2) ... ABS(NABS) Rec#2: Microwindow absorbers
[CHN(1) CHN(2) ... Rec#3+: Microwindow channels
(if NCHN present)
... CHN(NCHN) ]
Limb-Viewing
[ISEQ] MICLAB WNOMIN WNOMAX ALTMIN ALTMAX [IDXABS(1) IDXABS(2) ... IDXABS(NABS)] Single record
Spectral Filters
MICLAB ABS(1) ABS(2) ... ABS(NABS) [ALTMIN=ALTMIN] [ALTMAX=ALTMAX] Single record
MIPAS Microwindow Database File(s)
MDBFIL=MDBFIL Single record

Fields
Field Type Description Units Range
MICFIL Cn Name of a Microwindow file, eg miclist.txt
MICLAB C8 Microwindow Label, eg NH3_0001
WNOMIN D Microwindow Lower Boundary cm-1 0 < : ≤ WNOMAX
WNOMAX D Microwindow Upper Boundary cm-1 ≥ WNOMIN
Nadir-Viewing only
NABS I No. of absorbing species ≥ 1
NCHN I (Optional) No. channels/points to use within microwindow 1 : NPt
ABS(NABS) C7 Names of absorbers[2], eg 'CO2', 'co2', 'F12'
CHN(NCHN) I (If NCHN set) Channel indices within microwindow[4] 1 : NPt
Limb-Viewing only
ISEQ I (Optional) Microwindow number in sequence (ignored) e.g., 1, 2, ...
ALTMIN R Minimum tangent altitude[5] km < ALTMAX
ALTMAX R Maximum tangent altitude[5] km > ALTMIN
IDXABS(:) I HITRAN/RFM indices of absorbers 1 : 184 (see List)
MDBFIL C MIPAS Microwindow Database File
Type: I=Integer; D=Double Precision; Cn=character string, length n.

Notes
  1. For Nadir-viewing, there is a minimum of two records per microwindow, with 3rd and subsequent records determined by the presence and value of NCHN. For limb-viewing there is a single record per microwindow, although further information may be provided (for MIPAS) via Microwindow Database files (*MDB section)

  2. See subroutine 'molidx_sub.f90' for full list of acceptable names, all converted to lowercase.

  3. All retrieved species are considered as absorbers for all microwindows whether they are explicitly listed here or not.

  4. CHN(:): Microwindow channels are the indices of spectral points at the L1B resolution within the microwindow, so a channel #1 corresponds to WNOMIN and channel #NCHN corresponds to WNOMAX.

  5. ALTMIN, ALTMAX: These are based on the nominal tangent heights, i.e. position in scan limb-scan sequence, rather than actual tangent heights. Suggested values of 0, 120 if microwindows to be applied over all altitudes.

Examples
Nadir-viewing, direct entry of microwindow information in driver table
*MIC NH3_0001 930 940 4 5 ! use 930-940cm-1 range, 4 absorbers, 5 channels nh3 co2 h2o o3 930.75 931.0 931.25 931.5 931.75
Limb-viewing, indirect entry giving names of files holding microwindow, plus (MIPAS) microwindow database containing spectral mask info. information
*MIC pt_016.lst ! pT microwindows MDBFIL=MW_PT__510.DAT ! pT FR mode database