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    The ATM values are saved in binary files which use an ad-hoc format  (in
    particular, this is not the Gildas Data Format). They are Fortran unfor-
    matted (binary) files, usually read in direct access mode with 128 words
    (512  bytes) records. The values are written in the current machine sys-
    tem (IEEE, EEEI, ...); this system is saved as the very  first  word  in
    the file.

    The  file  consists  in a succession of tables describing the opacities,
    atmospheric emission, and optical length in the space of pressure,  tem-
    perature, frequency, water vapor, and airmass. The values in the tables,
    and the tables themselves, are written contiguously (no blanks  inserted
    e.g. no alignment on the records). Here is the exact sequence:

    Code    C*4  [     ]  System code

    Np      I*4  [     ]  Number of pressure values
    Nt      I*4  [     ]  Number of temperatures
    Nf      I*4  [     ]  Number of frequencies
    Nw      I*4  [     ]  Number of precipitable water vapor amounts
    Na      I*4  [     ]  Number of airmass values

    P[Np]   R*4  [HPa  ]  Pressure values
    T[Nt]   R*4  [K    ]  Temperaure values
    F[Nf]   R*4  [GHz  ]  Frequencies
    W[Nw]   R*4  [mm   ]  Precipitable water vapor amounts
    A[Na]   R*4  [     ]  Airmass values

    tauox[Nf,Nt,Np]        R*4  [neper] Opacity (dry component)
    tauw[Nf,Nt,Np]         R*4  [neper] Opacity (wet component)

    Temis[Na,Nw,Nf,Nt,Np]  R*4  [K    ] Atmospheric emission
    Path[Na,Nw,Nf,Nt,Np]   R*4  [cm   ] Optical length

Gildas manager 2018-08-15