Weather

Study and revision resources

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Definitions

Weather: the short term atmospheric conditions

Climate: the longer term average atmospheric conditions

Stevenson Screen

These are used to standardise the way that weather temperatures are recorded around the world.

They are a white wooden box structure that is raised 120cm off the ground to reduce the effect of heat radiated from the ground surface.

The white colour reflects sunlight and they have slatted sides to allow air to flow through.

Thermometers and hygrometers are kept in Stevenson screens, barometers may also be placed in there to shelter from the rain.

Stevenson Screen
Figure 2.41: Stevenson Screen

Instruments for Measuring the Weather

You need to be able to describe how the different types of weather are measured and give the units of measurement.

Tasks

For each of the weather types below,

  1. Draw a simple diagram of the instrument
  2. Describe how the weather is measured
  3. Suggest a suitable location for the instrument.
Weather Instrument Measurement
Precipitation Rain guage Milimeters
Air pressure Barometer Milibars
Wind speed Anemometer km/hour
Wind direction Weather vane Compass directions
Temperature Thermometer (max-min) Degrees centigrade
Humididity Hygrometer Percentage
Cloud cover Eyes Oktas

Many weather recording instruments are now digital - with the data being logged straight into spreadsheets.

barometer
Figure 2.42: Barometer

Cloud Types

There are several distinct cloud types that you should be able to recognise and describe their characteristics.

Cirrus: high clouds that are thin and wispy, composed of ice crystals (Fig 2.44).

Cumulonimbus: towering storm clouds with dark bases and usually an anvil shaped top (Fig 2.48).

Cumulus: dense, mound shaped clouds with a darker bottom (Fig 2.45).

Stratocumulus: common low lying cloud that appears layered. Like flattened cumulus clouds (Fig 2.46).

Stratus: low, hazy, featureless clouds that often bring light rain/drizzle (Fig 2.47).

cumulonimbus clouds
Figure 2.48: Cumulonimbus clouds
cirrus clouds
Figure 2.44: Cirrus clouds
cumulous clouds
Figure 2.45: Cumulus clouds
stratocumulus clouds
Figure 2.46: Stratocumulus clouds
stratus clouds
Figure 2.47: Stratus clouds

Climate Graphs

You should be able to accurately draw climate graphs - remember to label the axis and give it an appropriate title.

You are expected to be able to read and interpret the data shown in climate graphs and suggest reasons for the trends shown.

climate graph
Figure 2.49: Climate Graph
Content for Accordion Panel 5