Cumulus Support

In this plot:
http://img824.imageshack.us/img824/3451/cumrelpress.png
I show a comparison between my barometer and the one in an AWS which is about 200 m away. Over the few days of record, there was quite a large variation in atmospheric pressure.

The stats of the difference are:
Mean: 0.123 hPa - this is just an offset
Std Dev: 0.322 hPa - this is the important number
Skewness: 0.126 - close to zero
Kurtosis: -0.120 - close to zero

which means that the errors are normally distributed and for 95% of the time, my barometer is within +/- 0.6 hPa of the AWS.

What this shows is that our barometers that cost a few dollars are almost as good as the Vaisala in this AWS which cost more than $1,000.
Not bad, eh?

When I last did some comparisons, my Fine Offset barometer tracked my Davis VP2 barometer quite closely, and similarly the outside temperature. For other readings, it wasn't so good. Rainfall, wind and humidity were all considerably different. Wind comparisons are a little unfair as they're not quite mounted at the same height.

Yes the barometer does seem fairly accurate when it's in an aspirated container (fan on top of extended sensor unit) and doesn't suffer from too many temperature and humidity problems.
Tracks my Altimeter quite well now.
Mike.

That's good to hear.

My rain gauge is proving to be very consistent with 2 manual rain gauges I have in the garden. My FO gauge is currently reading 101.2mm for the month and one of my manual gauges which is over 5m from any structure is reading about 102mm and the other is reading over 105mm, but that one is too close to the house and I suspect is getting some spray off the roof in very heavy falls.

I can't compare the wind to any other stations though as we're on the southern side of a large hill (Mt Lofty) and tend to get slightly different wind conditions to the rest of Adelaide.