How to calculate the daily average radiation
The daily average radiation is measured for the hours the sun is up. Consider whether to include the first and last hours, as these may not contribute fully to the average. Similar to the hourly radiation, the radiation values from KNMI weather data column Q have to be multiplied:
,
where:
- is the first full hour with sun radiation.
- is the last full hour with sun radiation.
| Column | Name | Unit | Dutch Description |
|---|---|---|---|
| 2/B | YYYYMMDD | Date | datum (YYYY=jaar,MM=maand,DD=dag) |
| 3/C | HH | Hour | tijd (HH=uur, UT.12 UT=13 MET, 14 MEZT. Uurvak 05 loopt van 04.00 UT tot 5.00 UT |
| 13/L | Q | J/cm2 | Globale straling (in J/cm2) per uurvak; |
Notes
- The values at each hour regard the measurement over the preceding hour up to that time. To obtain the value for August 2nd, all Q values from August 2nd where sun radiation is present must be used (e.g., hours 7 through 19 UTC).
