How to calculate the hourly radiation

According to the DPRA Heat stress report:

"De globale straling van het KNMI station is een som van het afgelopen uur. Om de hoeveelheid straling op het hele uur te schatten wordt de straling van het komende uur en afgelopen uur gemiddeld."

So the global radiation for the hour has to be calculated as the average of the past hour and the next hour. We use the Q column from the KNMI weather data for this. Additionally, the global radiation is in J / cm² and has to be converted to W / m² by multiplying:

$radiation_{hourly}={\frac {Q_{t}+Q_{t+1}}{2}}\cdot {\frac {10000}{3600}}$

Column	Name	Unit	Dutch Description
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 10am, the values at 10am and 11am must be used.

See also

• Hourly radiation (Heat Overlay)
• KNMI weather data