The distribution of all observations within one month timespan is represented by the quartiles Q1, Q2 and Q3. The station and month specific reference quartiles Q1', Q2' and Q3' is calculated from the climate database either by the previous ten years or from a regional reference station.

A neighbour station n is selected with a corresponding set of quartiles Q1n, Q2n and Q3n. The neighbour station also have the station and month specific reference quartiles Q1'n, Q2'n and Q3'n.

An error is detected when

|Q1 - Q1'| - |Q1n - Q1n'| > tol1 and |Q1 - Q1'| > tol2

or

|Q2 - Q2'| - |Q2n - Q2n'| > tol3 and |Q2 - Q2'| > tol4

or

|Q3 - Q3'| - |Q3n - Q3n'| > tol5 and |Q3 - Q3'| > tol6

where

tol1 - tol6 are six tolerance values.

• QC2d-4

It shall be possible to run the algorithm for

• UU
• NN
• HL
• VV
• QO

CONTROLINFO AND/OR USEINFO

• none

TYPEID, OTHER METADATA

• all typeid

SPECIFICATION OF CONTROLFLAGS TO BE SET FOR EXPECTED RESULTS OF THE ALGORITHM, I.E. CONSIDER BOTH POSITIVE AND NEGATIVE RESULTS

• fstat=1 on no error detection
• fstat=2 on error detection

EXPECTIONS OF THE USEINFO FLAGS CORRESPONDING TO CONTROLINFO FLAG SETTINGS

• fstat=2 → useinfo(2)=2

• Definition of neighbour station
• Definition of regions and related region reference station
• Extracts from KDVH