Hello,

Some laboratories, particularly physics departments working on solar cells, have a calibrated solar illuminator to test their prototype solar cells. I would suggest taking a trip there with your pyranometer and having them illuminate it at various intensities. Alternatively, you could also use a standard silicon solar cell in photovoltaic mode for comparison.

I would like to suggest looking at the following place:

www.bom.gov.au/climate/austmaps/about-solar-maps.shtml

Dear Joseph Nyangon, thanks for your reply.

I measured global solar irradiation (horizontal) at a 1-min step during summertime, by means of a silicon pyranometer. It is hard to find data to compare my readings to. I am doing a double-check measurement in comparison with a second pyranometer to verify the reliability of the readings and so far both instruments are in agreement, although we didn't reach that high solar radiation these days. Is it physically possible that the radiation went so high? In that case what might be the trigger/the cause/the noise? A high level of pollution may have risen the recorded value through scattering?

Thanks,

Reflection from clouds can significantly increase radiation when direct radiation is not obscured by clouds.

Vladimir Kubov is correct in that you can have direct sun and reflection from clouds. Most solar radiation sensors use a clear sky model as a way to compare values. The most common is the Bird model refs below:

R. E. Bird, "A simple, solar spectral model for direct-normal and diffuse horizontal

irradiance," Solar Energy, vol. 32, pp. 461-471, 1984.

R. E. Bird and C. Riordan, "Simple Solar Spectral Model for Direct and Diffuse

Irradiance on Horizontal and Tilted Planes at the Earths Surface for Cloudless

Atmospheres," Journal of Climate and Applied Meteorology, vol. 25, pp. 87-97, Jan

1986.

You can get higher values than what is predicted using the Bird Model in cases of reflection from clouds and/or from ground objects (buildings).

Dear,

I would like to suggest you to find input and output information of weather station, producer refferences and provide propere place. Second, if doubt is gone about tools, you must calculate with variable weather and clouds, radiation from Sun, impact of reflection and refraction, an nearlest of hight buildings around measured place etc...

I hope that you concern this suggestion.

Best regards!