Hi Benno,
This isn't really a comment on your email, but a question (only somewhat
related) occurred to me. When you store multiple trajectories (or
forecasts), each started from a difference reference, but sampled in the
same way (at equal intervals), how should this be done? Suppose, for
example, you want to store ozone data from 10 freely moving balloons,
with samples taken hourly following release (for 24 hours), but each
balloon released at a different time. Would you do this as follows?
dimensions:
time = 24 ;
ref_time=10
variables:
float O3(time,ref_time) ;
O3:long_name = "mole_fraction_of_ozone_in_air" ;
O3:units = "1e-9" ;
O3:coordinates = "lon lat z" ;
double time(time)
time:standard_name = "elapsed_time??? or relative_time???"
time:long_name = "elapsed time since the beginning of the trajectory"
time:units = "hr"
double ref_time(ref_time) ;
ref_time:standard_name = "reference_time???" ;
ref_time:long_name = "time when balloon was released and the reference for
elapsed_time (relative_time)"
ref_time:units = "days since 1970-01-01 00:00:00" ;
float lon(time,ref_time) ;
lon:standard_name = "longitude" ;
lon:units = "degrees_east" ;
float lat(time,ref_time) ;
lat:standard_name = "latitude" ;
lat:units = "degrees_north" ;
float z(time,ref_time) ;
z:standard_name = "height_above_reference_ellipsoid" ;
z:units = "km" ;
z:positive = "up" ;
Note the possible standard_names (I think, suggested by others).
Best regards,
Karl
On 5/17/11 8:46 AM, Benno Blumenthal wrote:
CF has standard names forecast_reference_time, forecast_period and
time which are interrelated in a particular way.
I have a trajectory dataset which also has reference_time, period,
and time which are interrelated in the same way, but forecast is not
an appropriate descriptor: the reference_time is the start of the
trajectory, the period is the time relative to the start_time along
the trajectory.
I am wondering how important "forecast" is in the semantics of these
particular standard_names -- does it really have to be a forecast?
After all, these are the standard names for the time coordinates, e.g.
independent variables, while forecast is a property of the dependent
variables, i.e. how they were computed.
Do we need more general names? Am I taking the current names too literally?
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