Weather and Climate Chapter Notes | IGCSE Oxford Geography Foundations for Year 6 - Class 6 PDF Download

Weather affects our lives in many ways.

For example, it affects:

• the sort of activities we do
• the type of clothes we wear
• what we plan to do at the weekend
• where and when we go on holiday.

How might you observe and record the weather?

• Weather is the condition of the air around us over a short period of time, characterized by temperature, precipitation, wind, and cloudiness.
• Meteorology is the scientific study of weather, where meteorologists measure and record weather features daily using various instruments.
• Observation Techniques:
  1. Temperature: Indicated by people’s clothing; measured with thermometers.
  2. Precipitation: Includes rain, snow, sleet, and hail; observed by water falling to the ground.
  3. Wind Speed: Estimated by observing smoke and trees; measured with the Beaufort scale.
  4. Cloud Type: Identified by shape, size, and height; common types include cumulonimbus, cumulus, stratus, and cirrus.
  5. Wind Direction: Shown by a wind vane.
  6. Cloud Cover: Measured in eighths of the sky covered.
  7. Visibility: Measured in meters.
  8. General Weather: Described using terms like rain, snow, showers, fog, mist, thunder, cloudy, fair, or sunny.

How can local features affect temperature and wind?

• Microclimate: A small area’s climate that differs from the general surroundings.
• Influencing Factors:
  1. Physical Features: Trees, water bodies, and hilltops can affect temperature and wind patterns.
  2. Buildings: Emit heat and can alter wind speeds and directions.
  3. Surface: The color and material of the ground surface influence warming.
  4. Aspect: The direction a place faces affects its temperature.

What is Britain’s weather?

• Climate vs. Weather: Climate is the average weather over many years, while weather is the day-to-day state of the atmosphere.
• British Climate Characteristics:
  1. Temperature Variations: Higher in summer than in winter; not uniform across Britain.
  2. Rainfall Patterns: Occurs year-round with regional variations; influenced by geographical features.

How does it rain?

• Rain Formation: Involves the condensation of moist air that rises, cools, and forms cloud droplets, which grow into raindrops.

• Types of Rainfall:
  1. Relief Rainfall: Occurs when moist air rises over mountains.
  2. Convectional Rainfall: Caused by ground heated by the sun, leading to rising warm air.
  3. Frontal Rainfall: Happens when warm air rises over colder, heavier air at a front.

Forecasting the Weather - Anticyclones

• Anticyclones are weather systems associated with high air pressure and typically result in good weather.
• Air Pressure: The weight of air pressing down from above; varies from place to place.
• Formation: Anticyclones form in areas of above-average pressure.
• Characteristics:
  1. Cool air sinks in anticyclones, leading to high pressure.
  2. They are indicated by clear skies and calm weather.
  3. Satellite images can show anticyclones as areas with little cloud cover.

Forecasting the Weather - Depressions

• Depressions are low-pressure weather systems that often bring clouds and rain.
• Air Movement: In depressions, air rises, cools, and condenses to form clouds.
• Development: Occurs where warm air meets cold air, creating a front.
• Features:
  1. Depressions are large areas of low pressure.
  2. They appear on satellite photos as swirls of cloud in a ‘V’ shape.
  3. The center of a depression is usually near the point of the ‘V’.
• Impact on Britain:
  1. Depressions commonly form over the Atlantic and move eastwards across Britain.
  2. They are responsible for much of the cloudy and rainy weather in Britain.