Weather and climate

Weather and climate

1. Atmospheric and oceanic cirulation

   • Weather
     • Weather is something that we experience everyday
   • Climate
     • Climate is the average weather over a long period of time (30 years)
   • Coriolis effect
     • The deflection of air due to the rotation of the Earth
   • Jet stream
     • Fast moving current of air in the upper atmosphere at the boundary of Polar and Ferrel cells (where there is a significant temperature difference)
   • Gulf Stream
     • The Gulf Stream (also known as the North Atlantic Drift) brings warm water from the Caribbean Sea across the Atlantic Ocean to the UK
   • Hadley cells
     • on either sides of the equator
   • Ferrel cells
     • In the middle of the Hadley and Polar cells
   • Polar cells
     • In the north and south poles
   • Atmospheric circulation
   • Oceanic cirulation

2. Global climate

   • Natural causes of climate change
     • Milankovith cycles
       • Eccentricity cycles
         • More circular orbits mean cooler periods and more elliptical orbits mean warmer periods
       • Precession cycle
         • More circular orbits mean cooler periods and more elliptical orbits mean warmer periods
       • Axial tilt
         • Greater angle of tilt means hotter summers and colder winter
     • Solar radiation
       • The solar energy from the sun
     • Surface impact
       • steroids and comets eject large volumes of ash and dust which blocks out the solar radiation from the sun, reducing temperatures
     • Volcanism
       • Ejects smoke and ash created from volcanoes blocks out the solar radiation from the sun, reducing temperatures
   • Evidence of climate change
     • Historical evidence
       • Diaries may include past climate information
     • Ice cores
       • Volcanic ash, microbes and air bubbles are trapped
     • Tree rings
       • Wider rings mean more rainfall and thinner rings mean less rainfall. Scars means wildfires 
     • Preserved pollen
       • Pollen is trapped in rocks and ice cores and provides evidence on warm and cold weather conditions
   • Greenhouse effect
     • more heat escapes and less heat is re-emitted
   • Enhanced greenhouse effect
     • less heat escapes and more heat is re-emitted and is caused by humans
   • Fossil fuels
     • Coal, oil and natural gas
   • Quaternary period
     • The quaternary period is the current period of geological time

3. Global climate changing due to human activity

   • Human causes
     • Industry
       • As levels of disposable income rises and increased demand for the production of consumer goods, more energy is needed resulting in more fossil fuels being burned
     • Transport
       • With cars becoming more affordable and more people taking flights over long distances, huge quantities are needed and this is made from burning fossil fuels which contributes to the enhanced greenhouse effect
     • Energy
       • The demand for electricity is growing because of increasing population and technologies. This is produced through burning fossil fuels
     • Farming
       • Population growth has lead to a higher demand in food production. Mechanisation means that more fossil fuels are being burnt, intense farming of cattle results to an increased production of methane and we purposefully impregnate cows to produce more meat 
   • Negative effects of climate change
     • Lower crop yeilds
     • Rising sea levels
     • Flooding
     • Increase in food prices
     • Retreating glaciers

4. UK's distinct climate

   • The UK has a temperate wet climate. Extreme weather is rare but the meeting of major air masses makes frontal rainfall common
   • Climate past and present
     • Little Ice Age
       • Lower temperatures and the River Thames froze. This lead to crop failures and extreme volcanic eruptions and a decrease in solar radiation
     • Medieval period
       • Higher temperatures and the UK were able to grow grapes. This meant more solar radiation and low volcanic activity
     • UK has temperate climate surrounded by water
   • Factors influencing UK's climate
     • Prevailing winds
       • The main prevailing wind in the UK comes from the south-west and this air travels long distances over the Atlantic Ocean bringing moisture and rainfall
     • Altitude
       • The higher an area is, the cooler and wetter it is. Areas in the UK vary
     • Atmospheric circulation
       • The UK is near the boundary between the Ferrel and Polar circulation cells. This is where warmer air from the south and cooler air from the north meet, causing unsettled weather
     • Maritime influence
       • Most of the air that reaches the UK contains lots of moisture and this gets released as rainfall all year round
     • North Atlantic Drift
       • This ocean current brings warm water north to the UK. In the winter, this makes the UK climate milder than would be expected
   • UK's geography
     • Maritime air mass
     • Continental air mass
     • Tropical air mass
     • Polar air mass
     • Surrounded by water