Redistribution of 24 hour precipitation

RR_24 is the precipitation collected over the last 24 hours. The Qc1 check precipcollected_flag identifies if an RR_24 value is valid (fd=1), erroneous (fd=3) or is the accumulation (fd=2) of a number (N) of consecutive 24 hour periods, where N>1. For the case fd=2, the accumulated value shall be distributed over the N 24 hours periods.

For each day the calculated

RR_24= model_value*observed_accumulation/sum_of_model_values

where the model values for the N missing values of RR_24 are calculated by an interpolation from the other stations making measurements at the same time and for which fd=1. At present, the interpolation uses an inverse 2-D squared distance weighting. Other weighting and interpolation techniques might be added later.

The calculated RR_24 updates the corrected value in the kvalobs database.

The standard configuration options detailed in the user guide also apply to Redistribution.

Further configuration options are:

• endpoint_cflags (default: fmis=4&fd=2) and endpoint_uflags (default: no constraints) specify the flags for accumulation endpoints. Endpoints not matching these flags will not be detected.
• missingpoint_cflags (default: fmis=3&fd=2) and missingpoint_uflags (default: no constraints) specify the flags for the missing points before the accumulation.
• before_cflags (default: fmis=[04]) and before_uflags (default: no constraints) specify the flags for a data point before the start of the accumulation period.
• neighbor_cflags (default: fd=1) and neighbor_uflags (default: U2=0) specify requirements for the neighbor stations used for the interpolations. Neighbor stations that do not match these flags will be ignored.
• warn_and_stop_cflags (default: fhqc=)0() and warn_and_stop_uflags (default: no constraints) define for which flags for the accumulation point or the missing points before the accumulation the only action should be to print a warning and stop.
• update_flagchange (default: fd=7;fmis=3→fmis=1;fmis=0→fmis=4) flags to change for the accumulation endpoint and the missing points.

• ParamId (no default) selects the parameter ids to use. The only value tested here is 110 (RR_24).
• tids accepted typeids
• measurement_hour (default: 6) specifies the hour at which the data are expected. Series containing data with other times will be rejected with a warning.

This algorithm has only been tested for paramid 110.