Setup barometer?

Question

Hi Guys, Does anyone know about barometers? where's the best place to put it in a house? I know how to adjust the barometer when new, there is a brass screw at the back that u adjust to the correct setting for your area and weather,,only prob is, ok its blowing like mad and is raining on and off, is there a site I can enter my postcode just like the weather on my right on my screeen that will give me the correct settings for my barometer to initial set up.

Answer 1

the met office site is busy just now but there you go....

The eurometeo site is pretty cool, check it out.


ps the mechanical ones are not that accurate, but they DO give a good indication. I doubt that you are talking about a mercury in glass one, as they do NOT have screws in the back?

Answer 2

I wrote a piece for a local radio station about barometers. here is part of it which I have modified a little:

The most common type of barometer is the aneroid barometer. Many people have one in the home. These barometers do not use liquid in a tube but a metal box from which some of the air has been extracted. As the air pressure rises, the box is compressed; as the pressure falls, the box expands. A pointer is attached to the box such that it swings right and left as the box contracts and expands. A calibrated card behind the pointer lets us read the pressure.

The barometer should be mounted on an internal wall, not one of the external walls with windows and doors in it. Air conditioning makes no difference to the barometer reading.

If a barometer is to be of any use, it must be set. The air pressure decreases with altitude so if we measure the pressure atthe bottom and top of a mountain at the same time, the recording at the top will be lower than at the bottom. We could set our barometers to the correct local pressure and this is called Station Level Pressure (SLP). It cannot, however, be compared with the weather maps on TV or in the newspapers as the pressures on those are all Mean Sea Level Pressures (MSLP). The various weather services read the barometers at SLP and then makes a correction to bring the reading to MSLP. You can bypass the correction by setting your barometer to MSLP. You can then make direct comparisons with the reports on TV or in the papers. If for some reason you need Station Level Pressure, you will have to make an appropriate adjustment.

Find the closest weather observing station to yourself and check their MSL pressure. Set your barometer to that. There is a screw in the back of the barometer that allows you to set the pointer. Don't worry about the pointer controlled from the front at this stage. Let the barometer settle down and the next day check the pressure again just after the hour when the new observation is posted. Reset your barometer - it will need only a fine adjustment. Do this once more and you will be ready. Check the setting every two months or so to keep it accurate.

The barometer should be read at the same time every day. When you read it, move the pointer control on the front until the needle sits over the barometer pointer. When you look at the barometer the next day you will be able to see if the pressure has risen or fallen. 9am is the traditional time for reading barometers but pick a time that suits you. There are tides in the atmosphere and the pressure falls from about 9am to about 3pm, rises to 9pm, falls to 3am and then rises again to 9am. Toricelli noticed this with his barometer. The movement is called the "diurnal variation of pressure" and this is why the barometer must be read at the same time every day.

The units we use to measure air pressure are hectoPascals (hPa). This is the same figure as the earlier millibars (mb). Even earlier, and still in the USA, the pressure was given by the height of the mercury column in inches of mercury. The liquid must be specified as it could just as easily be a lot more inches of red wine.

Answer 3

I hope you are talking about a Mercury in glass barometer.
First you must set the Barometer to sea level plus your local altitude.

Next you must set the barometer to a pressure. The weather channel will list pressure for areas from time to time.

Then you must zero your pointer to the meniscus every day to take a reading.

Finally you must correct for ambient temperature, there should be a thermometer incorporated into the barometer. If you can't be bothered with the last one put the barometer where temperature changes are minimum.

PS Enjoy your pressure watching.