"[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/rmia5uv4ztb.fsf%40s1.lexort.com.
