[CF-metadata] Example of forecast data

From: Jonathan Gregory <j.m.gregory>
Date: Wed, 11 Jun 2003 17:01:07 +0100

Dear Brian and Ag

It might be nicer in Ag's example to have a single variable. This could be
done with a size-one validity time dimension and a size-three forecast time
dimension. You could still have a forecast period:

dimensions:
  timea=3;
  timef=1;
variables:
  double timea(time1);
    timea:standard_name = "analysis_time";
    timea:units = "hours since 2003-01-01 00:00" ;
  double fperiod(timea);
    fperiod:standard_name="forecast_period";
    fperiod:units="hours";
  double timef(time2);
    time3:standard_name = "forecast_validity_time" ;
    time3:units = "hours since 2003-01-01 12:00" ;
  float temp1(timef,timea,level,lat,lon);
    temp1:long_name = "Air temperature on model levels" ;
    temp1:standard_name = "air_temperature" ;
    temp1:units = "K" ;
data:
  timea = 0., 6., 12.;
  fperiod=12., 6., 0.;
  timef = 0. ;

However, the forecast period may not really be necessary as it should be
pretty easy to subtract the analysis time from the validity time.

Brian's other example is the reverse case of multiple forecasts from one
analysis time. The idea of using the reference time in the time units to
indicate the analysis time, and thus eliminate a size-one dimension, is neat
but I wonder if it is really robust? It means that one could not reprocess
the time units without care. Usually the reference time could be changed in
time units (altering the time values consistently) without any consequence.

Best wishes

Jonathan
Received on Wed Jun 11 2003 - 10:01:07 BST