weather

Cards (25)

  • Weather: Short-term day to day changes in the atmosphere in a place.
  • Climate: The average weather conditions in a particular area over a long period of time.
  • Stevenson Screen:
    • Double roof to protect from sun's heat.
    • Painted white to reflect sun's heat.
    • Raised 110 cm above ground to avoid effects of ground surface.
    • Slated sides to allow entry of air.
    • Wood not metal, as metal conducts heat.
    • Sited in open space to avoid external influences e.g. heat from buildings.
  • Inside a Stevenson Screen:
    • Sometimes a barometer - air pressure.
    • Wet-and-dry bulb thermometer - indicates the humidity of the air.
    • Maximum - minimum thermometer - records the max and min temp.
  • Advantages of using digital instruments:
    • Greater accuracy.
    • Human errors are removed.
    • More exact readings.
    • Automatic recording.
    • Instant analysis.
  • Record cloud types:
    • Choose same times during the day over a period of one week.
    • Observe of several times each day.
    • Identify cloud types using shape of clouds.
    • Estimate cover.
    • Record names of cloud types in a table/chart.
    • Record clouds in eights.
  • Wet-and-dry bulb thermometer:
    • Measures humidity
    • Read off wet and dry bulb temps.
    • Use relative humidity table/chart.
    • Work out difference between the two.
    • Read off figure at intersection of dry bulb and wet bulb depression figures.
  • Barometer: Measures air pressure in millibars.
  • Max/min thermometer: displays the maximum and minimum temperatures of the day
  • Wet/dry bulb thermometer: measures humidity.
  • Rain gauge: Measures rainfall. Should only be placed on grass.
  • Main features; rain gauge:
    • On grass, to avoid splashes entering the gauge.
    • Part buried to prevent evaporation and stability.
    • No trees overhanging to prevent drips entering the gauge.
    • Away from buildings to avoid too little rain entering.
    • Stand vertically upright to keep the correct diameter.
    • The height of the water in the small cylinder measured.
  • Cloud cover:
    • The amount of sunshine reaching the ground depends on the amount and duration of any cloud cover.
    • Given in units called oktas.
    • Each okta represents one eigth of the sky covered by cloud.
  • Heliograph:
    • Records the amount of sunshine at a given location.
    • Burns a timeline.
    • Traces sunshine not hours of daylight.
    • The ball focuses the light and burns a line onto the cord.
  • Wind vane: checks direction of wind.
  • Anemometer: measures wind speed in mph/kph or m/s.
  • Why should an anemometer be on the roof?
    • If higher up, no interference from trees and buildings.
    • It will not be sheltered, ground may be sheltered by buildings.
    • On the roof it cannot be damaged by people.
    • Results will be accurate.
    • No wind chanelling.
  • Westerly wind: blows from west to east.
  • Cirrus clouds:
    • Found in high atmosphere - usually over 5,500 metres.
    • Common throughout the world.
    • Thin and wispy in appearance.
    • Move fairly quickly.
  • Stratus clouds:
    • Low level - below 2,000m and sometimes reaching ground.
    • Usually grey and move fast.
    • Can produce light rain and snow.
  • Cumulonimbus clouds:
    • Large clouds up to 10 km high and across.
    • They resemble a giant cauliflower.
    • Produce rain, thunder and lightening.
    • Usually found in spring and summer.
  • Cumulus clouds:
    • Fairly low clouds with bottom between 600 m and 1,200 m.
    • Looks like lumps of cotton wool.
    • Can produce light rain.
    • Individual clouds have a short life cycle.
  • Relief rain: Rain that falls on the ground and is absorbed by the soil.
  • Frontal rain: Rain that falls in a straight line from the front of a storm.
  • Convectional rain: Rain that is formed when warm air rises and cools, causing water vapour to condense.