Sunday, 27 December 2009

Using weather instruments - fieldwork techniques

In this post I am going to list 13 instruments used in meteorology. In the case of flooding we will use these instruments as well as other methods and instruments such as using a GIS map or studying land-use. Images can be found below.
  1. Stevenson screen: It is an instrument designed to shield meteorological instruments against precipitation and heat radiation. As well as at the same time allowing air to circulate freely around the device. 
  2. Anemometer: This is a device used to measure wind speed and direction.
  3. Soil Thermometer: This measures the temperature of the soil.
  4. Digital thermometer: This takes more precise and accurate readings (to 0.1°) than analogue thermometers.
  5. Maximum-Minumum thermometer: For a given period they will give you the range of temperatures e.g. 5-15°. 
  6. Rain Gauges: After 24 hours of being outdoor the device is collected and the amount of water is measured.
  7. Barometer: It measures pressure and there are three types; aneroid (needle), water and mercury. The most popular are aneroid.
  8. Ventimeter: Another device used to measure wind but it more accessible as it is more cheaper. However, it does not work in low wind conditions.
  9. Beaufort scale: This is qualitative data based on individual subjective descriptions. A great way to understand this is to watch this 24 sec video: .
  10. Campbell- Stokes Sunshine recorder: It is used to record sunshine hours.
  11. Light-meter: Meteorologists measure heat radiation from a light reader. However, the light-meter will record reflected light as well as incident light.
  12. Wet and Dry hygrometer: It consists of two thermometer look-like devices and reading are taken of both of them. According to the magnitude of the difference between them we can see how humid a place is. However, it is not suitable for microclimate measurements.
  13. Whirling Psychrometer: This device is whirled above the head (rather like a football rattle) for 1 minute and readings of the two thermometers are taken.

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