Author Topic: Barometer vs Pressure  (Read 591 times)

staze

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Barometer vs Pressure
« on: May 07, 2020, 08:33:41 pm »
Hi All,

Wondering if anyone knows off hand if the data exported from WC for the Pressure field is the actual station data real pressure, or if it's the calculated barometer.

See: https://github.com/weewx/weewx/wiki/Barometer,-pressure,-and-altimeter

Basically trying to figure which is appropriate to import into Weewx from a WC export. =) (no, I'm not going to stop using WC, I just like some of the output from WeeWX).

Thanks!
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elagache

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Believe it to be calculated - ask Stu? (Re: Barometer vs Pressure)
« Reply #1 on: May 07, 2020, 11:54:15 pm »
Dear staze and WeatherCat manual experts,

. . . . .
Wondering if anyone knows off hand if the data exported from WC for the Pressure field is the actual station data real pressure, or if it's the calculated barometer.
 . . . . .

Wow!  I would have expected there would be something in the manual that would clearly explain one way or the other.  However, the closest I could come to that is a caution with regard to the Fine Offset stations that WeatherCat needs the attitude set correctly in order to provide accurate barometric pressure.  I just remembered that Davis stations also provide the computed barometric pressure, so WeatherCat doesn't have access to anything else for us Davis users.

So I would put the odds at above 80% that WeatherCat stores the computed barometric pressure with the adjustment for attitude.  However, if you want to be 100% sure, you might try contacting Stu.  For a quick question like that, you might be a timely reply.

Thanks for asking!  It is a far more interesting question than I first imagined!

Cheers, Edouard  [cheers1]

staze

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Re: Believe it to be calculated - ask Stu? (Re: Barometer vs Pressure)
« Reply #2 on: May 08, 2020, 12:51:10 am »
Dear staze and WeatherCat manual experts,

. . . . .
Wondering if anyone knows off hand if the data exported from WC for the Pressure field is the actual station data real pressure, or if it's the calculated barometer.
 . . . . .

Wow!  I would have expected there would be something in the manual that would clearly explain one way or the other.  However, the closest I could come to that is a caution with regard to the Fine Offset stations that WeatherCat needs the attitude set correctly in order to provide accurate barometric pressure.  I just remembered that Davis stations also provide the computed barometric pressure, so WeatherCat doesn't have access to anything else for us Davis users.

So I would put the odds at above 80% that WeatherCat stores the computed barometric pressure with the adjustment for attitude.  However, if you want to be 100% sure, you might try contacting Stu.  For a quick question like that, you might be a timely reply.

Thanks for asking!  It is a far more interesting question than I first imagined!

Cheers, Edouard  [cheers1]

LOL! I did do a basic search first! =P

Will contact and respond back once I know! =)
"You mean, you'll put down your rock and I'll put down my sword and we'll try and kill each other like civilized people?"

staze

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Re: Barometer vs Pressure
« Reply #3 on: May 08, 2020, 04:08:47 am »
Have not heard back, but just realized the gauges say "Pressure (rel)" which makes me think it's Barometer, or pressure corrected to Sealevel.

Will wait for final judgement until I hear back from Stu.
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staze

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Re: Barometer vs Pressure
« Reply #4 on: May 09, 2020, 06:48:08 pm »
Guess not. I got:

"Yes, it’s just pressure as recorded, converted to user units."
"You mean, you'll put down your rock and I'll put down my sword and we'll try and kill each other like civilized people?"

elagache

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Live and learn. . . . (Re: Barometer vs Pressure)
« Reply #5 on: May 09, 2020, 10:38:18 pm »
Dear Staze and WeatherCat faithful,

Guess not. I got:

"Yes, it’s just pressure as recorded, converted to user units."

Okay, I'll try to remember that from now on.  I'm glad to hear that our harried fearless leader is still managing to get through his emails!

Cheers, Edouard  [cheers1]