SET ATMOSPHERE

###
SET ATMOSPHERE

            CLIC\SET ATMOSPHERE Argument Value /ANTENNA a1 [a2 ...]

        Selects  the  way atmospheric calibration is done by command ATMOSPHERE,
        Argument may be FILE, AUTO, TREC, or MANUAL. This will affect the anten-
        nas  given  in argument to the option /ANTENNA (/ANTENNA ALL selects all
        antennas). Argument may also be NEW, 2009, 2003, OLD,  1985,  to  switch
        between atmospheric model versions or INTERPOLATE to use tabulated atmo-
        spheric model (defined to be GAG_ATMOSPHERE) ; option  /ANTENNA  is  not
        required in that case.

          - In FILE mode the actual mode is taken from the data header,  as giv-
            en in the OBS program.

          - In TREC mode the receiver temperature is assumed known, to  set  the
            scale  of  measured sky temperature and optical depth, and determine
            the system noise temperature.  The  receiver  temperature  is  taken
            from  the  data header, as given in OBS.  It may be forced to a dif-
            ferent value by giving it as second argument 'value', or by the  SET
            TREC command.

          -  In AUTO mode the water wapor content is assumed  known;  it  is de-
            termined  from  the  antennas  in TREC mode, if any, or  taken  from
            the  data  header,  or forced  to  the  value  given  in  the second
            argument 'value', or by the SET WATER command.

        These parameters, together with the wheather station data, are  used  to
        compute  the system noise temperature for each antenna.  In MANUAL mode,
        no model atmosphere is used,  but  the  values  of  optical  depths  and
        atmospheric temperatures stored in the data.

          -  OLD  or  1985  select the old ATM model, in use at IRAM since circa
            1985.

          - 2003 select the 2003 version of the ATM model,developed by Juan Par-
            do  in  ISM  in Madrid. For this, the new ATM library must be avail-
            able. If not the old ATM  will be used.

          - NEW or 2009 (the default) select the  2009  ATM  model,developed  by
            Juan  Pardo  in  ISM  in  Madrid.  For this, the ATM library must be
            available. If not the old ATM will be used.

          - INTERPOLATE will use a tabulated file produced  by  ASTRO\ATMOSPHERE
            MAKE.  This  option should not be used, as the use of tabulated file
            is only used to speed up calculations at Bure.