.bin File

RFM File Formats: HITRAN Binary Line Data

21APR25
Type
Input, optional.
One of various forms of spectroscopic data for any line molecules (molecules ID#1:99).

Description
Binary, direct-access form of the HITRAN standard 160 character .par file, converted using HITBIN.

The actual binary file structure should be transparent to the RFM user, but is described here for information.

Filename
Specified in *HIT section of Driver Table

Structure
Direct access binary file with record length 88 bytes. The structure of this file owes much to its GENLN2 inheritance (i.e., not the way it would have been designed now!).
Lower case indicates variables not used by the RFM

File Structure
File_Header_Record First record in file
Comment_Record Optional record(s)
Repeat until end
    Forward_Pointer_Block[3] set of 4 records
    Data_Record typically x200
End_Record File termination

File Header Record
LSTAT IFMT IREC1 IREC2 head48
Comment Record
LSTAT cmnt84
Forward Pointer Record
For i = 1, 56, 14
    LSTAT MOL_OFF IDUM WNO IFP(i) ... IFP(i+13)
Data Record
LSTAT MOL ISO WNO STR tpr HWA HWS ELS TCA PSA IGU IGL LQU LQL spare9 IFP spare1
End Record
LSTAT IDUM IDUM WNO

Fields
File Header Record
Field Position Type Description Range
LSTAT 1:4 I4 Record-type identifier[1] 0
IFMT 5:8 I4 File Format identifier[4] 1
IREC1 9:12 I4 Rec# of first Data_Record 2 : < IREC2
IREC2 13:16 I4 Rec# of End_Record IREC1 < :
head48 17:63 C48 (eg) Brief file description
Comment Record
Field Position Type Description Range
LSTAT 1:4 I4 Record-type identifier[1] 4
cmnt84 5:88 C84 (eg) Further file description
Forward Pointer Record
Field Position Type Description Range
LSTAT 1:4 I4 Record-type identifier[1] −7
MOL_OFF 5:8 I4 MOL of 1st mol. in FP record ∈ {1, 15, 29, 43}
IDUM 9:12 I4 Dummy integer for padding 0
WNO 13:20 D8 Wavenumber[2], in cm-1 > 0
IFP(:) 21:76 14I4 No.records until next for this molecule[3] > 0
Data Record
Field Position Type Description Units HITRAN
LSTAT 1:4 I4 Record-type identifier[1], =10
MOL 5:8 I4 HITRAN molecule ID M
ISO 9:12 I4 HITRAN isotopologue local ID I
WNO 13:20 D8 Wavenumber[2] cm-1 ν
STR 21:24 R4 Intensity (line strength) @ 296 K[5] cm-1/(kmol.cm-2) S*
tpr 25:28 R4 Transition Probability Debyes2 ℜ
HWA 29:32 R4 Air-broadened half-width@ 296 K cm-1atm-1 γair
HWS 33:36 R4 Self-broadened half-width@ 296 K cm-1atm-1 γself
ELS 37:40 R4 Lower State Energy cm-1 E"
TCA 41:44 R4 Temperature dependence of HWA nair
PSA 45:48 R4 Air pressure-induced line shift@296K cm-1 atm-1 δair
IGU 49:52 I4 Upper state global (=Vib) quantum index V'
IGL 53:56 I4 Lower state global (=Vib) quantum index V"
LQU 57:65 C9 Upper state local (=Rot) quantum index Q'
LQL 66:74 C9 Lower state local (=Rot) quantum index Q"
spare9 75:83 C9 Spare bytes
IFP 84:87 I4 No.records until next for this molecule[3]
spare1 88:88 C1 Spare byte
End Record
Field Position Type Description Range
LSTAT 1:4 I4 Record-type identifier[1] −2
IDUM 5:8 I4 Dummy integer for padding 0
IDUM 9:12 I4 Dummy integer for padding 0
WNO 13:20 D8 Wavenumber[2], in cm-1 > 0
Type: I4=Integer (4 bytes); R4=Real (4 bytes); D8=Double Precision (8 bytes); Cn=character string, length n (n bytes).

Notes
  1. LSTAT: always the first integer (=4 bytes) in each record, used to determine the type of record

  2. WNO: Beyond the file header record and comment records, all records start with 3 integers (LSTAT plus 2 others) and then the double precision wavenumber, intended to allow rapid searching for a particular wavenumber without having to decode the entire record. Every record has a WNO value either equal or greater than the preceding record. Within Forward_Pointer_Records the WNO values are that of the next Data_Record.

  3. Forward_Pointer_Block: Every 200 data records there is a block of 4 records containing the Forward Pointers for every molecule, which is the number of records until the next occurrence of a Data_Record for each molecule. These are in addition to the forward pointer IFP contained in each Data_Record, which just gives the next occurrence for that particular molecule. If there are no more data records, IFP points to the End_Record.

  4. IFMT: HITRAN2020 defines molecule IDs up to #55, and this file format (specifically the definition of a forward pointer block of 4 records each containing 14 molecules) allows for a molecule ID up to #56. A new format may be required for the next HITRAN release (while maintaining backward compatibility with the current format).

  5. STR: Line Stengths in the HITRAN .par file are defined as [cm-1/(kg.molec.cm-2)]. These are multiplied by Avogadro's Number ( 6.0221367E26 ) for the binary file in order to ensure that the numbers are in the normal range which can be represented by exponentials.