ATM File Structure

16AUG22 - Web-page reformatted
Contents

Overview

ATM files contain an atmospheric profile as a function of height or pressure, or a list of just heights or pressures.

These are used to represent a 1-dimensional atmospheric profile for the Scene Generator component of the Cubemap End-to-End Simulator (actually the RFM .atm file format)

These files can also be used to specify climatological or a priori profiles for the L2 processor (although other methods of specifying these data for L2 are also available).

Example: equ.atm, which can be read with IDL function read_atm.pro

File Structure

The file contains a header section consisting of an arbitrary number of comment records followed by a single number: the number of levels in the profiles.

The data section consists of an arbitrary number of profiles but all of the same number of data points.

A record starting '*END' is used to indicate the end-of-file.

All numerical data are read "free-format".

File Structure Overview
File_Header_Section Defines NLev
Profile_Data_1 NLev data values
Profile_Data_2 NLev data values
... etc.
End_Marker

File Header Section
!CMNT Comment record(s) (optional)
NLev No. levels in profiles
Profile Data
!CMNT Comment record(s) (optional)
*PRF_ID Profile label (separate record)
PRF(1), PRF(2) ... Block of NLev Profile values
... PRF(NLev)
End Marker
*END End-of-file marker

Data Dictionary

Field Type Description Units Range
!CMNT String*80 Comment records first character is '!'
NLev Integer No. levels in profiles ≥ 1
*PRF_ID String*20 Identifier for profile type [1]
PRF Float(NLev) Data values of PRF_ID profile [1]
*END String*4 End-of-file marker '*END'

Notes

  1. *PRF_ID is a contiguous string starting with a '*' character as the first character in the record. Anything in the record beyond the first space is ignored. The following Profile labels *PRF_ID are recognised by MORSE/RFM as input data (all converted to lower case internally) - anything else is ignored
    *PRF Profile Units
    *HGT Altitude km
    *TEM Temperature K
    *PRE Pressure hPa
    *AEROSOL Extinction km-1
    *[mol] Volume Mixing Ratio ppmv

    where [mol] (eg *H2O), which is actually assumed to be anything other than those listed in the above table, is compared with the list of molecular absorbers specified for inclusion in the RFM or MORSE, and ignored if not listed.

Document Changes

16AUG22 Web-page reformatted
27JUL22 Original