Which PVGIS

[JohnS]

I note there are many different flavours of PVGIS.

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

has two; Classic PVGIS and Climate-SAF PVGIS, and I have seen various references to PVGIS 4.

Does anyone have a view of which is considered the most accurate/best or whatever or know over which periods the data was compiled?

I am in the process of compiling sunshine hours from the Met Office historical records and want to compare it to PVGIS.  There is a +7/-3.4% variation in annual sunshine hours depending on whether one takes a 40 year period (1971-2010) or a 10 year period (2001-2010).  Thus I want to match sunshine records to PVGIS as best I can.

John

[GavinA]

climate saf is the satellite one, the other is using weather station data anyway, so depending which weather stations you're using you could end up comparing like with like.

[skyewright]

When I (and I believe others) refer to sometimes as "PVGIS-4" I/we usually mean a calculation done using the "Climate SAF" database and the apps4 version of the PVGIS URL, i.e. the one quoted in the first post in this topic.

The Climate SAF option first became available in the apps4 version.

...know over which periods the data was compiled?

The "Whats This" link on the PVGIS page gives quite a detailed description of the basis for the two different radiation databases.

http://re.jrc.ec.europa.eu/pvgis/apps4/databasehelp_en.html

[JohnS]

Skyewright

Thanks.  Based on the 'What's this' link, I shall use June 1998 to May 2010 as 12 years of sunshine hours data to compare to PVGIS.

John

New CM-SAF - PVGIS database for Europe and Northern Africa
These data are based on calculations from satellite images performed by CM-SAF (see also references 4 and 5). The database represents a total of 12 years of data. From the first generation of Meteosat satellites (Meteosat 5-7), known as MFG, there are data from 1998 to 2005 and from the second-generation Meteosat satellites (known as MSG) there are data from June 2006 to May 2010. The spatial resolution is 1.5 arc-minutes (about 3km right below the satellite at 0° N, 0° W). The coverage extends from 0° N (equator) to 58° N and from 15° W to 35° E.