The Result of Uncalibrated Barometers....

[6719jason]

Hello,

I was on WU Today and noticed a rather high pressure reading from a nearby Station and this is clearly the result of uncalibration - See http://www.wunderground.com/weatherstat ... =ISUFFOLK2

Just a heads up here

It is worth adding....that at the time of this post...there was a 40HPA difference between this station and those in the surrounding area...Including Met Office Stations!

[Repairman77]

I have two military stations near me at Mildenhall and Lakenheath and the barometers as well as the hygrometers (far worse) can be very different, although they are only about 2 miles apart.
The barometers are in sync today at 993.00 but the Hygrometers are showing 80.9% and 93.2%!
I'd guess the second one to be somewhere near as mine is showing 84%.

While we are on the subject of accuracy has anyone ever tested the accuracy of the WH1080/90 series of anemometers?
I've often wondered how accurate they are.

Mike.

[RCE]

Looking at the history for the month doesn't look far off, and then 14th & 15th silly readings, back to normal ish, then back to what I assume is full scale on the 26th

[gemini06720]

I was on WU Today and noticed a rather high pressure reading from a nearby Station and this is clearly the result of uncalibration...

Jason, what make you think that your station barometer is better calibrated than the one displaying its results on Weather Underground?

When you installed you station, did you get some high-precision instruments to calibrate your weather station (and I do not mean using the data from nearby weather stations) - and do you regularly recalibrate your station using those same high-precision instruments? I think not...

Our weather stations are as accurate/precise (and calibrated) as our knowledge of our weather stations goes ... and of the instruments we initially use to calibrate and we regularly use to recalibrate our weather stations ... no more, no less...

[Gina]

I calibrated mine against the Met Office station at Dunkeswell air field, just a few miles away. The best I could do. I check again every so often when the pressure is fairly even over the area.

[6719jason]

I was on WU Today and noticed a rather high pressure reading from a nearby Station and this is clearly the result of uncalibration...

Jason, what make you think that your station barometer is better calibrated than the one displaying its results on Weather Underground?

I have no real answer to that, like Gina, I calibrated mine and do reguarly using nearby Airports and Met Office Stations. Mine also keeps in line with a Davis station nearby - A Vantage Pro 2 I think from memory

When you installed you station, did you get some high-precision instruments to calibrate your weather station (and I do not mean using the data from nearby weather stations) - and do you regularly recalibrate your station using those same high-precision instruments? I think not...

Not at all. When I first set up the station, I knew little about what I was doing. Still dont really. In short, No. If I could afford those high precision instruments, I wouldnt have a Fine Offset station.

Our weather stations are as accurate/precise (and calibrated) as our knowledge of our weather stations goes ... and of the instruments we initially use to calibrate and we regularly use to recalibrate our weather stations ... no more, no less...

Yeah.

Will be replying to your email as soon as I can.

WWS

[EvilV]

I expect the pressure sensors are pretty accurate. Mine certainly keeps in line with my oldfashioned wall barometer, and also with the one at the airport nearby.

The most likely inaccuracy of any barometer system will be in the offset that is introduced to bring it into line with the convention of giving Relative Pressure - the pressure at sea level. If there is a high pressure system over an area with few isobars on the weather map, you can align yours to a trusted, nearby station. But if you know the precise altitude of your station above sea level, you can use this Java calculator to work out exactly how much offset to put in. Once that is done, you shouldn't fiddle with it again.

http://www.csgnetwork.com/barcorrecthca ... m=990.2990

If you want to know your exact station altitude, you can use Google Earth to find it.