Hi Greg Many thanks for your reply, you raise some very valid points about data in the real world. Maybe I'll just leave it as it is :)
Cheers Colin On Sun, 13 Aug 2023 at 11:16, Greg Troxel <[email protected]> wrote: > "[email protected]" <[email protected]> writes: > > > Hi all > > I have a situation whereby (I think) I have some odd building > reflections > > spiking my solar radiation sensor. This results in occasional readings > way > > above the expected maxSolarRad value. > > I'm going to try and sort out exactly what's happening but in the > meantime > > I wondered if it would be possible to use StdCalibrate to correct those > > errant readings? > > Putting it simplistically what I'm aiming for is a statement along the > > lines of; > > > > radiation = maxSolarRad if radiation > maxSolarRad > > > > I'm not sure if that syntax is correct above or will even work, but > this > > will hopefully remove any spikes greater than the expected maxSolarRad? > > > > Am I barking up completely the wrong tree? > > Yes. You have data and you should record it. > > There are three situations, at least, where you will measure a radiation > that is higher than maxSolarRad. > > - small amounts, because the formula is approximate > > - reflections from mirror-ish surfaces resulting in direct plus extra > > - lensing from cloud edges, where you see = in clear sky, lower in > cloud, and a messy pattern as the edge happens > > In these cases, you really can get measurements that are valid and above > maxSolarRad. > > The question is: what are you trying to do and what do you think it > means? > > If you are trying to find some value that represents the highest value > you saw more than momementarily, compute the 98th percentile of > radiation, or 95th or 99th. Then the data means what it says. > > As soon as you extract data with a conditional on theory, you have > something that is very hard to reason about and describe. My advice is > don't go there. > > This is different from rejecting values of 120% humidity reveived from a > sensor as obviously bit errors. Seeing too-high radiation happens > without corruption. > > > I just record it, and graph it, and I don't worry that it's sometimes > higher than theory. Real data is like that. > > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/CACjxfUsz36A026ft9YyH25SKNOuRYL4NCCUJPdkyMqHoQMB5pw%40mail.gmail.com.
