pressure readings

[PeterP]

Hi Steve,
i was just wondering if it would be possible to adjust the configeration of Cumulas so that it displays air pressure as either "rel" or "abs", ( I believe it to be set on rel at present).

My weather station (ws1083) can display air pressure in either relative or absolute, and here in NZ the met service, TV and press all seem to use abs, and I can only configure it in Cumulas to mb, hPa or inches and it never corresponds to everything else, and there is quite a big difference between rel and abs, unlike mb or hpa.

it would be great if we could all sing from the same songbook.

cheers,
PeterP

[steve]

Are you sure they use absolute pressure? It's useless for meteorological purposes, this is why Cumulus doesn't display it.

[beteljuice]

"" .. it would be great if we could all sing from the same songbook. "

That's why it should be 'Relative' - also called 'Mean Sea Level Adjusted'

The NZ met service make very little mention of pressures, or anything by way of explanation, but all the Synop charts and METAR are Sea Level Adjusted - I know there are several (new) personal stations who have not set up correctly.

Here's a link you may find useful:

http://www.nzweather.net/

[PeterP]

Thanks for the replies folks. The only way I have found to get anything to co-relate is
a) to leave the station in abs, and;
b) adjust the calibration offset on Cumulas to +18 pressure.
This seems to have put things in sync a bit better. There is another weather enthusiast online 30km east showing a very similar pressure, and Terry (aka Super-T) is approx 40k west and posting similar readings. Its probably not ideal, but it does seem to work.

[steve]

The 'correct' way to do it is to calibrate the station so that its 'relative' value is the same as a reference reading somewhere near you, preferably during a time of stable pressure. Then you don't need to use a calibration setting in Cumulus, the station should continue to track the correct relative pressure. Are you saying that doesn't work for you?

[PeterP]

Hi Steve, your advice, once again, is spot on. Thanks again.

[steve]

I've moved this to the Fine Offset section - the 'WS' threw me for a while, but having Googled, it seems the WS1083 is a Fine Offset. I'm just pointing this out in case you didn't know that it was, and the information will be useful to you.