Jacques Terrettaz schrieb am Dienstag, 7. Mai 2024 um 13:07:08 UTC+2: The term "sunshine" and "sunshine duration" is the one used by WMO - see https://library.wmo.int/viewer/68695/?offset=#page=331&viewer=picture&o=bookmark&n=0&q= .
And this link reads: "According to WMO (2010), sunshine duration during a given period is defined as the sum of the time for which the *direct* solar irradiance exceeds 120 W/m^2." Note the word "*direct*". The sensor, most private weather stations use, measures the global irradiance, that is from the sun as well as from the sky. So there the threshold of 120 W/m^2 does not apply. Nevertheless, people use it that way. The pyrheliometer can measure the direct solar irradiance, only. And I hope, that shadow device can be (and is) calibrated precisely enough. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/01c77bd6-2e7b-450c-99e9-e53468f58030n%40googlegroups.com.
