How can I see the hourly Temperature data in Meteonorm 6, at PVsyst6 or PVsyst5

[Konstantina]

Hello again,

I am wondering if I can see the exact hourly or daily data of the Temperature file in PVsyst 6 or 5, regarding the database Meteonorm6 in order to be able to compare them with other dagtabases such as NASSA and PVGIS.I have tried to open the file with the Temperqture but I only see the monthly values.

Thank you!

[André Mermoud]

You can display the temperature hourly values in "Meteo tables and Graphs" / page "Tables".

However you will not be able to compare anything.

When genetating hourly values from monthly ones, the series of days and hours is constructed randomly: each generation will give you a completely different time series.

The only meaningful temperature comparison is in monthly values.

NB: the NASA-SSE usually gives significantly lower values than other sources, for 2 reasons:

- the temperature is defined for 10 m altitude (not 2m as any meteo data),

- the temperature is the average over the whole area of 1°x 1° (1° latitude = 111 km). If you are in montaneous regions, the temperature is taken at the average altitude, which may be much higher than the "living" altitude.

[Konstantina]

ok, now I understand the differences but about irradiance between Meteonorm and NASSA is the other way around.NASSA over estimates these values because it uses satellite measurements so the errors that occur and the quality control is much harder, right?