Which PWS sensors are most significant for Weather Intelligence factors?

[yukitz75]

I have seen threads discussing the following PWS data inputs are used with Weather Intelligence rain skip & climate skip features:

• temperature
• wind speed
• precipitation
• solar radiation

I would like to get an idea of which ones are the most significant for WI.

I have been using a local PWS a few miles away from me. It is a DVP2 unit, temp & wind have been pretty good, but barometer reading has been off based on the MADIS QC. Is barometer changes used by WI?

I recently setup my own PWS (Acurite 5in1) I understand it is not the most reliable unit, but I figured it is a good enough PWS to get started. I realized the unit is lacking the solar radiation & UV sensors. How significant are they for WI?

I am planning to choose the best local PWS based on the data importance factors. Once I know which ones are significant, I can monitor several PWS in my neighborhood (including mine) to determine which one provides the most accurate data for the most significant data input.

I realize what I am asking is probably a part of Rachio’s secret sauce for their WI algorithm, but some hints would be appreciated.

Thanks, yuki

[franz]

I have been using a local PWS a few miles away from me. It is a DVP2 unit, temp & wind have been pretty good, but barometer reading has been off based on the MADIS QC. Is barometer changes used by WI?

Not a factor for our equation.

I recently setup my own PWS (Acurite 5in1) I understand it is not the most reliable unit, but I figured it is a good enough PWS to get started. I realized the unit is lacking the solar radiation & UV sensors. How significant are they for WI?

I’ve done comparisons and without solar radiation data our algorithm gets close enough, so definitely don’t worry about that. The most accurate thing helpful is precipitation. We take a proprietary blend of PWS and National data to derive evapotranspiration (ET). We lean heavier on National data for factors like wind due to the fact that it is a huge component of ET and most installations of PWS with wind is not reported correctly.

I am planning to choose the best local PWS based on the data importance factors. Once I know which ones are significant, I can monitor several PWS in my neighborhood (including mine) to determine which one provides the most accurate data for the most significant data input.

I’d focus on precipitation.

I realize what I am asking is probably a part of Rachio’s secret sauce for their WI algorithm, but some hints would be appreciated.

At some point I’d like to opensource our algorithms and allow the community at large to make suggestions and make them better. Definitely in the future and in a perfect world I’d expose all of them.

[yukitz75]

This is great info. Thanks.

There is no rain during the summer where I live in California. I would be much more interested in the next factor in ET calculation after the precipitation. Micro climate seems to be a bit more extreme where I am located; I cannot depend on a generic city provided weather info since the temperature sensors info (we have a few remote Acurite sensors) seems to indicate hotter summer & cooler winter temperatures than the city reported data (I am guessing the data is actually derived from a NOAA airport location in a next city)

I want the best local data I can get for the Rachio input parameters. I wish to avoid frost damages to my trees in the winter & minimize over watering during summer (we have been in drought for a few years) for fruit trees & vegetable plants in my garden.

BTW, I suspected you & Emil are insiders based on the content & info you share. It is great you (co-founder) are providing this service, even on holidays. Much thanks.

yuki

[franz]

There is no rain during the summer where I live in California. I would be much more interested in the next factor in ET calculation after the precipitation.

The inputs are min temp, max temp, humidity, dew point, wind, and solar radiation. If we don’t have solar radiation we use elevation, day of year and latitude.

If you want to know the basis for the equation and seriously geek out, it is built out of this paper.

http://kimberly.uidaho.edu/water/fao56/fao56.pdf

BTW, I suspected you & Emil are insiders based on the content & info you share. It is great you (co-founder) are providing this service, even on holidays. Much thanks.

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