Author Topic: Interesting conversation with ECC re: barometer calibration  (Read 514 times)

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Offline gszlag

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  • ..have you calibrated your barometer today?
    • Michael's Bay - Manitoulin Island weather
I think we all agree that calibrating our baros are complex enough but then there is the unexpected.

For pws owners that compare readings with METAR and Mesowest, sometimes things go askew.

In my case, Environment Canada/NAVcan data readings for my local METAR did not match Mesowest.

Say whaat?

Nope. Station pressure and Altimeter were different between ECC and Mesowest.

Emails to ECC confirmed that the elevation was wrong at Mesowest. Not by a huge amount but it was out by 3 meters (approx. 10 feet). Significant enough if you are calibrating.

I also found out that  airport station pressure is calculated to the highest point  of the runway(s). I had assumed elevation was based on aerodrome elevation but that was not correct. I knew that in aviation, station pressure is a calculated amount as sensor height is corrected down to field elevation.

For our personal weather stations we normally assume station pressure = sensor pressure at whatever the sensor height is so it is a measured pressure.

Kudos to Mesowest responding instantly and they will be correcting my airport's elevation forthwith.

I could sleep soundly tonight except for one nagging thought..how did Mesowest get the right SLP with the wrong elevation?
Ambient Weather WS-2000
Ecowitt GW1000/GW1100
Ecowitt WS68: Anemometer, UV/solar
Ecowitt WH40: Rain gauge
Ecowitt WH57 Lightning sensor
Ecowitt WH32E: Outside T & H sensor
Stratus Rain Gauge (manual)
Raspberry Pi 3B+ (WeeWX/CumulusMX)
Raspberry Pi Zero 2W WeeWX/MQTT/Belchertown)
---
http://weather.glenns.ca (pwsdashboard - live)
http://weewx.glenns.ca
http://glenns.ca/cumulusmx2/index.htm
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Offline gszlag

  • Senior Contributor
  • ****
  • Posts: 288
  • ..have you calibrated your barometer today?
    • Michael's Bay - Manitoulin Island weather
Re: Interesting conversation with ECC re: barometer calibration
« Reply #1 on: June 25, 2022, 07:15:13 AM »
Not quite there yet.

Elevation for CYZEhas been corrected from 193 meters to 190. No decimal meters in Mesowest? At least we are closer to true elevation. However, station pressures do not match with the source data nor does Mesowest match NOAA/NWS CYZE Altimeter(setting).

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More emails required...
Ambient Weather WS-2000
Ecowitt GW1000/GW1100
Ecowitt WS68: Anemometer, UV/solar
Ecowitt WH40: Rain gauge
Ecowitt WH57 Lightning sensor
Ecowitt WH32E: Outside T & H sensor
Stratus Rain Gauge (manual)
Raspberry Pi 3B+ (WeeWX/CumulusMX)
Raspberry Pi Zero 2W WeeWX/MQTT/Belchertown)
---
http://weather.glenns.ca (pwsdashboard - live)
http://weewx.glenns.ca
http://glenns.ca/cumulusmx2/index.htm
---
Uploading to: AWN, ecowitt.net, Weather Underground, PWSweather.com, AWEKAS, Windy.com, WOW

 

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