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Earth's Climate
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Earth's Climate

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  • the greater the tilt, the greater the temperature difference is between summer and winter
  • this wobble affects the amount and intensity of solar energy that is received by the northern and southern hemispheres at different times of the year. This variation determines whether the two hemispheres have similar contrasts between seasons, or whether one hemisphere has greater temperature differences between seasons than the other hemisphere does.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.
  • energy from the moving air is transferred to the surface of the water, which causes the water to move.

Earth's Climate Earth's Climate Presentation Transcript

  • Earth’s Climate
  • Weather vs. Climate
    • Weather = the environmental conditions that occur at a particular place at a particular time
  • Toronto Weather Forecast
  • Weather vs. Climate
    • Climate = the average weather conditions that occur in a region over a long period of time (usually a minimum of 30 years )
    • The climate of an area is affected by four main factors…
    • 1.) Latitude
    • 2.) Elevation
    • 3.) Air masses
    • 4.) Nearness to water
  • Terrestrial Biomes
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  • Toronto’s Climate
  • Weather vs. Climate
    • Weather
    • short-term (a few days)
    • immediate
    • unpredictable
    • Climate
    • long-term
    • fairly predictable
    • Energy from the sun is the single most important factor that affects climate on Earth
    • Solar energy travels through space as light and heat
    • The intensity of the the energy that reaches Earth’s surface affects the temperature of the air , water and land on the planet.
    • This heat produces the winds , rain and other features of the climate .
    • The amount of solar energy that reaches Earth’s surface varies with changes in solar activity as well as Earth’s orbit around the sun.
    • Measurements of solar radiation show that irregular fluctuations occur in the amount of energy produced by the sun.
    • In addition, a more regular solar cycle (or sunspot cycle) occurs approximately every 11 years . These solar variations differ by about 0.1%
    Sunspot Cycles
    • Earth rotates (spins) once every 24 hours around its axis.
    • While continuously rotating on its axis, Earth orbits the sun once a year .
    Movement of Earth
    • The combination of Earth’s annual orbit around the Sun and its tilted axis produces our seasons
    Movement of Earth
    • Throughout Earth’s history, its orbit , tilt and rotation have varied slightly in repeating cycles
    Changes in Rotation, Orbit & Tilt
    • These variations change the amount and location of solar radiation reaching Earth, which also produce changes in climate
    • However, these changes do not fully explain all of the recent changes that have been observed and measured using other evidence .
    Changes in Rotation, Orbit & Tilt
    • Due to the gravitational attraction of other planets, Earth’s orbit fluctuates slightly over a cycle of about 100,000 years .
    Eccentricity
    • The angle of Earth’s tilt on its axis changes by approximately 2.4 o over a period of 41,000 years.
    Tilt
    • Also, because the Earth is not a perfect sphere , it wobbles slightly as it rotates on its axis.
    Wobble
    • Recall that Earth’s atmosphere extends from Earth’s surface up to about 560 km into space.
    • The atmosphere is composed mainly of nitrogen (N 2 ), oxygen (O 2 ), water vapour (H 2 O), as well as very small concentrations of other gases
    • Earth’s atmosphere absorbs thermal energy from the Sun as well as thermal energy that is emitted by Earth’s surface .
    • This process, called the greenhouse effect , is a natural part of Earth’s climate system.
    Natural Greenhouse Effect
  • Natural Greenhouse Effect
    • Greenhouse Effect = the natural warming caused when gases in Earth’s atmosphere absorb thermal energy that is radiated by the Sun and Earth
    Natural Greenhouse Effect
    • This process helps keep Earth’s temperature fluctuations within a certain range . Without this process, most of the solar energy reaching Earth would radiate back into space .
    • Wind is the movement of air from an area of high pressure to an area of lower pressure.
    Wind
    • All winds begin as a result of uneven heating of Earth’s surface. This movement of air transfers thermal energy around the world from warm areas to cooler areas.
    Wind
    • This movement of air affects ocean currents and precipitation patterns.
    Wind
    • The movement of currents at the surface of the oceans is driven by winds blowing over the water. These air currents are known as prevailing winds .
    Wind
    • Winds also affect precipitation .
    • When air masses meet, one air mass usually rises over the other.
    • The rising air cools , and any water vapour in the air condenses to form precipitation.
    Wind
    • Winds also affect precipitation through jet streams
    • Jet streams are high-altitude winds that travel long distances at very high speeds .
    Wind
  •  
    • Oceans cover about 2/3 of Earth’s surface
    • Recall that all the water in its different forms on Earth composes the hydrosphere
    • Together with the atmosphere, the hydrosphere transfers heat from one part of the planet to another.
    Water
    • Oceans can hold much more heat than the atmosphere can, therefore oceans act as a heat reservoir that buffers temperature changes in the atmosphere.
    • Large bodies of water influence climate because water has a large specific heat capacity compared to other substances.
    • Specific heat capacity = the amount of heat required to raise the temperature of 1g of a substance by 1 o C .
    Water
    • As a result, the temperature of large bodies of water tends to change slowly and by small amounts.
    • The temperature of land masses changes more quickly and by larger amounts.
    Water
    • Because of their light colour , snow and ice reflect solar radiation.
    • The fraction of light or radiation that is reflected by a surface is called albedo .
    Ice and Snow
    • In general, light coloured surfaces reflect energy and dark surfaces absorb energy.
    • The ocean surface reflects about 7% of solar energy
    • By contrast, a snowy field can reflect as much as 80-90% of the solar energy that strikes it.
    Ice and Snow
  • Ice and Snow
  • Tectonic Activity Earth has about 12 major tectonic plates that move at a rate of a few centimeters each year. As a result, the shapes of the oceans and continents are always changing .
  • Tectonic Activity The changing distribution of land and water affects patterns of air and water circulation and the transfer of thermal energy around the world.
  • In addition, volcanic eruptions , (which generally occur at the boundaries of tectonic plates), spew ash and other particles called “ aerosols ” into the atmosphere.
  • Aerosols reflect solar radiation and have a cooling effect on the global climate.
  • This effect may last from a few years to several decades , until the particles are removed from the atmosphere by precipitation and settling .