[wxqc] Barometric Pressure Errors

[Tisha Hayes]

Hi,
Thanks for your feedback on my thread. Yes, I found that the elevation
setting in the Davis Vantage Pro2 was incorrect. Once I corrected the
elevation I was able to pull the accuracy to within 1 milliBar of the
closest "official" barometric pressure at the Gadsden Regional Airport.

I too have the same issues with the local airport elevation since it is at
530 feet AMSL and my ground elevation is 890 feet with the barometer mounted
at 915 AMSL.

Topographically I believe that my readings will differ from the nearest
airport as I am on the crest of a mountain (Lookout Mountain) and the
airport is down in the valley to the south (situated on the Gadsden Mushwad
Complex (geological)). Winds coming out of the west and southwest will need
to lift as they approach the mountain and my local conditions vary
significantly from 850' on Lay Springs Road to 1250' at the crest and down
to 590' at Owls Hollow Road. Eventually I want to situate several stations
across my property (3/4 miles wide East-West, 1/2 mile North-South). It is
noticably cooler up here than down in town and my thermometer in my car can
show up to a 10 degree difference in the four mile drive.

Thanks Again!

Tisha Hayes
Sr. Engineer

On 7/17/06, Thomas E. Salzer <tom.es at verizon.net> wrote:
>
> Hello,
> I stumbled across your barometer calibration thread while doing a search
> on
> barometry. I was wondering whether the problem was resolved, and what you
> concluded. I had no idea it was that complicated. However, it seems to me
> that everyone agrees on sea level pressure. The difference is how one
> makes
> corrections for altitude. If one simply uses elevation, they will get a
> different result than if dew point and temperature are included. I set my
> barometers to local airport postings, but the local airport is only 233
> feet
> above sea level, so a small calibration error might not be apparent.
> I hope to hear about your resolution of this matter.
> Best regards,
> Tom Salzer
>
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