This example represents a daily average valid on 2 January 2012 of a field produced by a re-forecast started on 20120101 00Z produced with the model version which is operational at 20130101 00Z. In this example, where the field is produced 6-hourly, the daily average valid on 20120102  is  the average of steps 24, 30, 36 and 42.

  • In bold, the values are fixed. They are meant to be used by all partners
  • In green, these are the values for the example.

 

Time ( daily average )
Start of re-forecast ( section 1 )

Octets

 

values

 Meaning of valuesgrib_api keys
12Significance of Reference Time 1Start of forecast 
13-14Year (four digits) 2012year of start of forecast

 

dataDate=20120101

dataTime=0

15Month 01month of start of forecast
16Day 01day of start of forecast
17Hour 00hour of start of forecast
Daily average ( section 4 template 4.61 )
18Indicator of unit of time range 1Hour 
19-22Forecast time24Start of forecast + forecast time = start of average periodstartStep=24
38-39Year of Model Version2013

 

 

when the forecast is run == when the version of the forecast used was operational

 

 

modelVersionDate=20130101

modelVersionTime=0


 

40Month of Model Version01
41Day of Model Version01
42Hour of Model Version00
43Minute of Model Version00
44Second of Model Version00
45-46year of end of overall time interval2012

 

End of average period

    


 

endStep=-48



47month of end of overall time interval01
48day of end of overall time interval 03
49hour of end of overall time interval 00
52number of time ranges 1Only one time statistics applied (average) 
53-56total number of data values missing in statistical process 0  
57

Statistical process used to calculate the processed field

from the field at each time increment during the time range

 0Average stepType=avg
58

Type of time increment between successive fields

used in the statistical processing

2

Successive times processed have

same start time of forecast, forecast time is incremented

 
59

Indicator of unit of time for time range

over which statistical processing is done

 116-hourly indicatorOfUnitForTimeRange=11
60-63

Length of the time range over which statistical

processing is done, in units defined by the previous octet

 4Daily average lengthOfTimeRange=4
64

Indicator of unit of time for the increment between

the successive fields used

116-hourly indicatorOfUnitForTimeIncrement=11
65-68

Time increment between successive fields,

in units defined by the previous octet

 1

Time frequency used to compute the daily mean

In the example, 1 means that  6-hourly outputs have been used to compute the average

 timeIncrement=1

 

Examples of grib2 headers: