| Octet No. | 
      Contents | 
    
    
      10
  | 
      Parameter category (see Code table 4.1)
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      11
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      Parameter number (see Code table 4.2)
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      12-13
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      Atmospheric chemical constituent type (see Code table 4.230)
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      14
  | 
      Source or sink (see Code table 4.238)
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      15-16
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      Transport model used (see Code table 4.333)
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      17-18
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      Requested by entity (see ON388 Table 0)
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      19-20
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      Scenario origin (see Code table 4.335)
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      21-22
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      NWP used (see Code table 4.336)
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      23-24
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      Release start year
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      25
  | 
      Release start month
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      26-27
  | 
      Release start day
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      28
  | 
      Release start hour
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      29
  | 
      Release start minute
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      30-31
  | 
      Wall clock initial time of execution (Year)
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      32
  | 
      Wall clock initial time of execution (month)
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      33
  | 
      Wall clock initial time of execution (day)
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      34
  | 
      Wall clock initial time of execution (hour)
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      35
  | 
      Wall clock initial time of execution (minute)
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      36
  | 
      Wall clock initial time of execution (second)
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      37
  | 
      Type of generating process (see Code table 4.3)
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      38
  | 
      Background generating process identifier (defined by originating center)
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      39
  | 
      Analysis or forecast generating process identifier (defined by originating center)
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      40-41
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      Hours of observational data cut-off after reference time (see Note)
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      42
  | 
      Minutes of observational data cut-off after reference time
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      43
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      Indicator of unit of time range (see Code table 4.4)
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      44-47
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      Forecast time in units defined by octet 43
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      48
  | 
      Type of first fixed surface (see Code table 4.5)
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      49
  | 
      Scale factor of first fixed surface
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      50-53
  | 
      Scaled value of first fixed surface
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      54
  | 
      Type of second fixed surface (see Code table 4.5)
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      55
  | 
      Scale factor of second fixed surface
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      56-59
  | 
      Scaled value of second fixed surface
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