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convertRadiationFromWattsToMegaJoules conversion factor of 0.0864

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    PedroJorgePereira

    Hi,

    Any update on this subject?

    Regards,

    Pedro

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    PedroJorgePereira (Edited )

    Hi,

    Update to my findings.

    Based on these findings, can you confirm that the SOLARRADIATION unit is [MJ m-2 day-1], instead of [megaJoules / square meter per hour] as described on rain machine formula and documentation?

    If the unit is [MJ m-2 day-1], then the above 0.0864 conversion factor present at convertRadiationFromWattsToMegaJoules, is correct.

    Regards,

    Pedro

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    RainMachine Nicholas

    Yes it's [MJ m-2 h-1] see here: https://github.com/sprinkler/rainmachine-developer-resources/blob/master/formula/formula.py

    fRs = 16.502 [MJ m-2 h-1] - measured incoming solar radiation. If == None it is estimated from fKrs and fTMinC/fTMaxC

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    PedroJorgePereira

    Nicholas, Thank you for confirming the formula.py unit.
    It looks like i am on a catch 22.

    Can you also confirm the unit returned by convertRadiationFromWattsToMegaJoules function (used in the CIMIS and FAWN historical parsers)?

    Thank you,
    Pedro

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    RainMachine Nicholas

    I will have to bring this up for development team to look into and if it's wrong to be corrected in the next update.

    Thanks for bringing this up to our attention.

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    PedroJorgePereira

    Nicholas,


    I am glad to help. I will keep my parser using the convertRadiationFromWattsToMegaJoules function for now.

    I look forward to hearing from you soon.


    Regards,
    Pedro

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    RainMachine Nicholas

    If there is an error it can probably go unspotted because if ET0 is returned by parser irrigation will use this value. If ET0 is not provided then the formula will try to calculate it using what parser provides. In some cases SOLAR RADIATION is not returned for all stations in CIMIS/FAWN so to really affect irrigation, CIMIS/FAWN will have to not send ET0 and send SOLAR RADIATION and probably this happens with a low chance.

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    PedroJorgePereira

    I do understand that for CIMIS and FAWN the error if it exists, do not have a high impact.

    However, on my use case, the personal weather station does not report the ETo, but it indicates the Solar Radiation in w/m2.
    I want to add the Solar Radiation reported into Rain-machine.

    If the formula.py is expecting [MJ m-2 h-1] but if the conversion function convertRadiationFromWattsToMegaJoules returns [MJ m-2 day-1] it does not seem right.

    Please, confirm the convertRadiationFromWattsToMegaJoules returned units.

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    PedroJorgePereira

    Hi,

    Any update on this?

    My PWS is returning the Solar Radiation in w/m2 and I would like to confirm how should I store this data. 

    Thank you,

    Pedro

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    RainMachine Nicholas

    Your conversion is correct, the one provided with RainMachine returns per day.

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