Time range values

Definition of the main concepts related to the description of time range and statistical processing for observed and forecast data:

• Validity time is defined as the time at which the data are measured or at which forecast is valid; for statistically processed data, the validity time is the end of the time interval.

• Reference time is defined as the nominal time of an observation for observed values, or as the time at which a model forecast starts for forecast values.

• The date and time in DB-All.e are always the validity date and time of a value, regardless of the value being an observation or a forecast.

• P1 is defined as the difference in seconds between validity time and reference time. For forecasts it is the positive forecast time. For observed values, the reference time is usually the same as the validity time, therefore P1 is zero. However P1 < 0 is a valid case for reports containing data in the past with respect to the nominal report time.

• P2 is defined as the duration of the period over which statistical processing is performed, and is always nonnegative. Note that, for instantaneous values, P2 is always zero.

The following table lists the possible values for pindicator and the interpretation of the corresponding values of P1 and P2 specifying a time range:

Value	Meaning
0	Average
1	Accumulation
2	Maximum
3	Minimum
4	Difference (value at the end of the time range minus value at the beginning)
5	Root Mean Square
6	Standard Deviation
7	Covariance (temporal variance)
8	Difference (value at the beginning of the time range minus value at the end)
9	Ratio
51	Climatological Mean Value
10-191	Reserved
192-254	Reserved for Local Use
200	Vectorial mean
201	Mode
202	Standard deviation vectorial mean
203	Vectorial maximum
204	Vectorial minimum
205	Product with a valid time ranging inside the given period
254	Istantaneous value