Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Weather instruments ppt for students

19,299 views

Published on

describes all weather instruments in detail

  • Be the first to comment

Weather instruments ppt for students

  1. 1. Weather Instruments Geography
  2. 2. Temperature • Max Min Thermometer • Six’s Thermometer – Max-Mercury – Min-Alcohol • Measures shade temperature (Stevenson’s screen) • Read off at bottom of the index (reset with magnet) • Read at eye level • Measured in ºC
  3. 3. Humidity • Wet/Dry Bulb thermometer • Hygrometer – Wick and reservoir of water • Comparison tables 1. Calculate depression of wet bulb (Dry – Wet) 2. Read off table • Measures in shade (Stevenson’s screen) • Units = % Relative humidity
  4. 4. Wind Speed • Anemometer – Cups or blades – Clear unobstructed location • Km per hour
  5. 5. Wind Direction• Wind Vane• Recorded on Wind Rose• Compass Directions
  6. 6. Air Pressure • Aneoid Barometer • Barograph – Plots changes in pressure • Millibars • Measured in shade (Stevenson’s screen)
  7. 7. Rainfall • Rain gauge • Siting factors – Clear view of sky – Recessed into ground – Approx 30cm above ground – Grassy surface (avoid splash back) – Read off at eye level • Regular intervals (24hours)
  8. 8. Sunshine• Sunshine recorder – Burns a timeline – Traces sun shine not hours of daylight• Glass ball focuses light• Burns line onto card• Units = Hours
  9. 9. Stevenson’s Screen• Houses temperature / humidity /pressure instruments• Features – Insulated roof – Painted white to reflect heat – Louvered (slatted) sides aid air circulation – Located 1.25-2m above ground
  10. 10. Cloud Cover • Cloud Mirror • Divide mirror into 16 equal squares • Lay mirror on ground with clear view of sky • Estimate cover • Units = Oktas

×