Very useful, Cameron. It looks like the R-S curve is quite a bit lower, maybe as much as 20% lower, at dawn and dusk, which seems to be when people are experiencing values higher than maxSolarRad.
On Wed, Dec 23, 2020 at 1:19 AM Cameron D <cgoo...@davidsoncj.id.au> wrote: > And then I forgot the attachment! > > > On Wednesday, 23 December 2020 at 7:18:31 pm UTC+10 Cameron D wrote: > >> I should have looked a bit more closely before posting! I used the >> solrad excel code from Uni Washington. >> I had adjusted my B&H parameters to represent quite clean air but forgot >> to match the Bras and RS code from default. >> If I: >> >> 1. reset the BH turbidity params to default, >> 2. adjust the Bras param down to 1.6 and >> 3. adjust the RS param to 0.84, >> >> then the curves are close to normalised at peak. The RS curve is still >> a somewhat poor representation at dawn and dusk, while Bras is probably >> close enough to BH that it's not worth the extra effort. >> The main advantage with B&H is the atmospheric moisture, which I think >> contributes significantly, but differently from the atmospheric turbidity >> parameters and changes the shape of the curve. So a single parameter cannot >> account for all variables. >> The safest bet might be to adjust the parameter for clear skies and then >> say that is an upper limit. >> >> On Wednesday, 23 December 2020 at 6:31:47 pm UTC+10 Cameron D wrote: >> >>> So the weewx python code says it is using the Ryan and >>> Stolzenbach model, which has a few approximations that don't work well in >>> some cases, and it looks like this is one of them. >>> >>> I've attached a plot comparing 3 insolation models predicting global >>> horizontal irradiation. >>> Bird and Hulstrom 1991 >>> Bras 1992 >>> and Ryan and Stolzenbach 1972 >>> >>> B&H has a lot more parameters to account for, but I have just thrown in >>> the date/location for Boston, using whatever parameters were in the >>> spreadsheet, and come up with the following comparison. >>> I used the B&H predictions for modelling my solar PV system and found it >>> gives very close results - or at least it did before my system got a bit >>> older. However R&S also gives results that aren't too bad in my location. >>> >>> I have the code in php, but no spare time at the moment to convert to >>> python. >>> >>> On Tuesday, 22 December 2020 at 2:19:29 am UTC+10 t...@tom.org wrote: >>> >>>> kk, glad you corroborated my observations. I am no expert in this for >>>> sure. I am just tired of all of the comments I get from visitors to the >>>> website about how my readings exceed theoretical max. I could remove the >>>> max, but that doesn't seem fun. >>>> >>>> I do not have the expertise to validate the way weewx calculates it nor >>>> am I even competent in Python, but for those who may, here is a link to the >>>> code: >>>> >>>> >>>> https://github.com/weewx/weewx/blob/d91635f3bc429f906d1f084c6a6bc8ee09fa1a27/bin/weewx/wxformulas.py#L332 >>>> >>>> >>>> >>>> On Sunday, December 20, 2020 at 1:26:31 PM UTC-5 kk44...@gmail.com >>>> wrote: >>>> >>>>> I found that thread interesting, so I added the column "maxSolarRad", >>>>> too. >>>>> >>>>> [image: dayradiation.png] >>>>> Readings of the console and the WeatherLinkLive device are quite the >>>>> same. And the readings of "radiation" are higher than "maxSolarRad". The >>>>> values I upload to the local weather network are well in the range of >>>>> other >>>>> stations nearby. >>>>> >>>>> >>>>> Greg Troxel schrieb am Sonntag, 20. Dezember 2020 um 17:58:01 UTC+1: >>>>> >>>>>> >>>>>> Greg Troxel <g...@lexort.com> writes: >>>>>> >>>>>> > Can someone share how to add maxSolarRad (when it is in the db) to >>>>>> the >>>>>> > graphs for the traditional skin? Can I graph radiation, max >>>>>> (observed), >>>>>> > and theory all at once, having three? >>>>>> >>>>>> The answer is to just add it and label it; it comes out in green >>>>>> after >>>>>> radiation in blue and max in red. Pro Tip: add it after >>>>>> radiation_max, >>>>>> which is the max of local observations, and don't stick the line >>>>>> after >>>>>> the radiation_max header and the 4 lines defining how max should be. >>>>>> >>>>>> >>>>>> [[[dayradiation]]] >>>>>> [[[[radiation]]]] >>>>>> [[[[radiation_max]]]] >>>>>> data_type = radiation >>>>>> aggregate_type = max >>>>>> aggregate_interval = 3600 >>>>>> label = max >>>>>> [[[[maxSolarRad]]]] >>>>>> label = theory >>>>>> >>>>> -- > 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/ef4b8a0b-110b-4e48-bb2e-50ebae8c8277n%40googlegroups.com > <https://groups.google.com/d/msgid/weewx-user/ef4b8a0b-110b-4e48-bb2e-50ebae8c8277n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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