MOO Reports:
Starting Your Own Weather Station

In this special MOO report, we will guide you through the steps of setting up your own weather station.  First of all you will need to pick a suitable site. The Met Offices around the world have internationally agreed the following criteria:

1. Over Short Grass
The temperature close to the ground depends on what the surface cover is. Different surfaces have different properties; readings obtained on different surfaces are not compatible. It was hence internationally agreed that Met Stations should be positioned over short grass. This is easy enough if you live in a temperate climate; but less easy if you don't!
   

2. Well Away From Trees
Trees can shade a site and change its meteorological characteristics and so locate your site well away from them.
   

3. Open Site
True temperatures and wind movement can only be calculated in the site in open. The ideal radius is 130m. Airfields are hence preferable and this is why many official Met Stations are located at them (for instance, Bournemouth International Airport). It is very difficult to find a suitable site and so this particular criterium is often neglected.
   

4. Flat Land
Flat land is required so that any unwanted readings can be eliminated. The most common of these is when cold air gathers in a hollow.
  In reality it is very difficult to stick to these strict guidelines. The BSMO weather station breaks the rules on two counts, as it is in the middle of a town. Don't be too worried if you can't find an appropriate site - your readings are never likely to be used in complex scientific research!   OK, now you've found your site, what else do you need? A space for your equipment is necessary. If you can get your hands on a Stevenson Screen, that's an excellent bonus. Otherwise, use a wooden box which is well ventilated and not directly exposed to the Sun. Met Office guidelines say that the box should be painted white. The box should be 1.3m above ground level to compensate for action layer readings.   What do you need at your weather station? Here is a list recommended by BSMO:

  • THERMOMETERS. These should record maximum, minimum and current temperatures. If you can a single thermometer that records all three - so much the better! You also need web bulb and dry bulb thermometers for calculating humidity.
  • HYDROMETRIC TABLES. Essential for calculating humidity.
  • BAROMETER. Used to record pressure.
  • ANEMOMETER. Can be used to calculate wind speed and direction. If you can't get an anemometer, then use a Beaufort Scale chart and a weather vane.
  • RAIN GAUGE.
Good luck and let us know how you get on! If you find it difficult to get hold of any equipment please e-mail weatherstations@bsmo.freeuk.com and we will try to advise you.

 

 

. 1999-2003 Justin Taylor / John Dray

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