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Energy transfer in the atmosphere and oceans


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Energy transfer in the atmosphere and oceans

  1. 1. Energy Transfer in the Atmosphere
  2. 2. What is the Atmosphere? Surrounds the Earth made up of layers of gases Argon , Oxygen , Nitrogen Exosphere, Thermosphere, Mesosphere, Stratosphere, Troposphere Different temperatures
  3. 3. The atmosphere and hydrosphere are the to essential parts of the climate system, Firstly as they both are able to absorb and store thermal energy , so they act as heat sinks. Secondly, by absorbing the energy and storing it, it creates a big impact on our atmosphere. Therefore energy transfer by the atmosphere regulates the temperature of the earth.
  4. 4. How Is Energy Transferred in the Atmosphere? Conduction, convection, radiation Conduction is when heat gets transferred in solids and fluids by molecules bumping into each other. Convection is when molecules (heat) moves throughout a liquid or gas. Radiation is when particles or waves are transferred in a medium or space, in the form of electromagnetic waves. Types of energy transferred : Kinetic, Potential, Thermal etc.
  5. 5. Radiation in the Atmosphere Source : Sun Radiation energy is absorbed, reflected, scattered, transmitted Most of the energy is absorbed Thermal energy = the energy present in the motion of particles at a particular temperature (Science Perspectives 10)
  6. 6. Absorption Turns energy into another type of energy, eg. Thermal energy Water vapor , carbon dioxide, ozone, major absorbing gases Clouds, atmosphere , land radiates energy back into space
  7. 7. Transmission Some energy passes through unabsorbed This creates atmospheric windows Only certain types of light can pass through, mostly visible light, some radio waves and infrared light Only a very tiny amount of UV light passes through or it would be very dangerous
  8. 8. Reflection Able to see around us because of reflection Atmosphere + Clouds reflect 26% of sunlight back into space Warmer during cloudy nights because energy radiated from the land gets reflected back down : The Blanket Effect
  9. 9. Scattering Small particles in atmosphere cause light rays to scatter into different directions Three types : Rayleigh, Mei , Non-Selective No transformation of energy, just distribution to different parts of atmosphere
  10. 10. Rayleigh Scattering Wavelength of radiated light is bigger than particle it’s travelling through Sky appears blue because of this Blue light = higher energy = smaller wavelength = more scattering
  11. 11. Mei Scattering Lower in the atmosphere Diameter of wave droplets same as wavelength Almost an equal amount of scattering of visible light so clouds look white/grey
  12. 12. Nonselective Scattering Even lower in the atmosphere Particle is greater than the wavelength of light Scatters light equally, therefore the sky looks whitish when there is a haze
  13. 13. Conduction Thermal energy Air is a really poor conductor of heat Conduction happens in really low level of atmosphere by the Earth’s surface (land) Cool air falls, hot air rises, hot air from the land rises and circulates through atmosphere
  14. 14. Convection Thermal energy Sea breeze, land breeze can be explained using convection Sea breezes occur during day time , when the sun-heated land heats the air by convection. The land heats the air above it more than the water heats the air above it because land absorbs more heat. Cold air = more dense Warm air = less dense. Warm air rises, cold air from water takes it’s place = sea breeze Land breezes occur during the night. Land becomes cooler quicker than water = land breeze
  15. 15. Convection Currents When the suns rays reaches the equator with greatest intensity, the air at the equator heats up and becomes less dense. The colder air moves the dense air above it, forcing the worm air up in the atmosphere, this creates a area of low pressure below it. When the warm air is high in the atmosphere, it spreads out towards the poles and cools down. And the cooler air sinks back to the earths surface, creating an area of high pressure These cold and warm air creates a circular current called a convection current.
  16. 16. Convection Currents con. A circular current in air and other fluids caused by the rising of warm fluid as cold fluid sinks Convection currents are one of the main way that energy is transferred in the atmosphere.
  17. 17. Prevailing Winds Air going from high pressure to low pressure = wind Prevailing winds = always blow in the same way Prevailing winds move around the Earth due to Earth’s rotation Carries warm air from equator to poles Takes warm water from ocean to the poles Prevailing winds moving over ocean carrying water to land and condenses = rain
  18. 18. Green house effect is a natural process whereby gases and clouds absorb infrared radiation emitted from earths surface and radiate it, heating the atmosphere and earths surface.
  19. 19. The ocean and atmosphere are connected. They work together to move heat and fresh water across the globe. Wind-driven and ocean-current circulations move warm water toward the poles and colder water toward the equator. The ocean can store much more heat than the land surfaces on the Earth. The majority of the thermal energy at the Earth’s surface is stored in the ocean. Thus, the absorption and movement of energy on the Earth is related to the ocean-atmosphere system.
  20. 20. Heat is transferred to the surface of the Earth from the hot Earth's core by conduction and from radiation from the Sun. The atmosphere is heated by absorption of some of the electromagnetic radiation from the Sun, and contact with the warm surface of the land and water. The warm land and water also radiates infrared, some of which is absorbed by the atmosphere, adding to its thermal energy. The remaining heat on the surface is sent out into space in the form of infrared radiation.
  21. 21. How does energy transfer in the atmosphere help the Earth? It blocks out/absorbs a lot of UV light, which is very dangerous in more than a little quantity It moderates the Earth’s temperature and keeps it stable Radiation brings sunlight to Earth and we need it to survive
  22. 22. Energy Transfer in Oceans
  23. 23. Water Bodies In every part of the world, the presence of large bodies of water is a contributor to climate differences. Water has a higher heat capacity than rocks or the atmosphere, meaning that oceans can store much more heat. During the summer days the land gets hotter than the nearby water and the warm air starts to rise above causing oceans to replace the rising air. During the winter the air over the land cools faster than air over water. The water from the ocean radiates some of its stored heat into the air and this warm air begins to rise. The cooled air over the land moves in to take its place. Oceans are considered as a heat sink because they can absorb and store thermal energy and lastly, serve as temperature buffers for the ocean and atmosphere system.
  24. 24. Water Bodies as Temperature buffers The northern hemisphere is 39 percent land and 61 percent ocean. The southern hemisphere is 19 percent land and 81 percent ocean. Due to larger portion of water in the southern hemisphere the land south of the equator experience an annual temperature variation by 7.3 degrees Celsius from summer to winter. In the northern hemisphere the variation could be up to 14.3 degrees Celsius.
  25. 25. Regional Climate The great lakes are also known for the strong moderating effect they have on the climate of the areas that surrounded these lakes. These huge water masses keep summer and winter temperature moderate, they also provide a lot of moisture.
  26. 26. Oceans are warmer near the equator than oceans near the polar region. The atmospheric circulation that is set up between the equator and the poles helps in the redistribution of water masses. Wind that blows over the ocean surface drags and starts to move the surface water, these currents are influenced by the Coriolis force. The Coriolis force is used to describe the effect of Earth’s rotation on the motion of moving objects. Ocean currents are influenced by the position of landmasses. In the Pacific currents correspond to the patterns of the surface winds; currents are more complex near the Indian and Atlantic Ocean. In the North Atlantic, the Gulfstream pushes the warm water towards the North Pole and cold air back towards the equator. Ocean Currents and Coriolis Force
  27. 27. The region that lies between 23.5 degrees north and 23.5 degrees south of equator is called tropics. This region receives a large amount of solar energy which creates a flow of warm current, which flows towards the poles. When the current reaches the poles it starts its journey back towards the equator, this process is defined by great ocean conveyor belt. In a conveyor the currents carrying warmer and less dense water move in one direction while currents carrying salty and cold water move in the opposite direction. The conveyor occurs due to two facts. First reason is due to the variation in water temperature, as warm water is lighter and less dense than the cold water. Second reason is due to the difference in amount of salt present in the ocean water. As freshwater is lighter and less dense than the salty water. Due to these two factors stated the creation of thermohaline circulation is created. Conveyor Belt and Thermohaline Circulation
  28. 28. Cycle of Ocean Current Within the oceans there is a sophisticated system of massive streams that helps to circulate the ocean waters. The gulf stream that moves into the North Atlantic sinks as it cools and returns south though the Atlantic seafloor, it then flows as a bottom current up until the South Atlantic form there it rises to the surface in the Indian Ocean and the Eastern Pacific to warm up and then turns west towards the Gulfstream. For a complete run through this current system takes about 1000 years. This current system is very delicate minor changes can upset the balance of temperature differences and prevailing winds. Scientists have said that the melting of the Greenland icecap can cause so much melt water of low salinity and density that this could prevent the Gulfstream from sinking and returning as a southward bottom current. This would affect the current system and cause waters near the equator and regions close to the equator to get warmer and northern Europe to get colder
  29. 29. Cycle of Ocean Current
  30. 30. Latent Heat The energy required to change the phase of a substance is known as a latent heat. The quantity of heat absorbed or released by a substance undergoing a change of state. Latent Heat can also be called Heat of transformation. The latent heat absorbed by air when water vapour condenses is primarily the source of the power of thunderstorms and hurricanes. EXAMPLE : The polar ice caps are examples of latent heat .
  31. 31. The Earth receives 174 petawatts of solar radiation at the upper atmosphere. 30% of that light is reflected back to space. And the other 70% is absorbed by oceans, clouds, and other land masses. Solar energy warms up the air and the latent energy makes the clouds rain . Solar energy keeps the surface level of the Earth at 14 degrees Celsius Water in general is evaporated due to solar energy, which eventually leads to condensation and precipitation. Solar energy and the Oceans.
  32. 32. Due to Energy transfer we get form solar energy and other forms we get different weathers. The Effects of the energy transfers in the future could result in melting Ice caps, higher sea levels , flooding, and warmer climate . The Polar Ice Caps absorb a lot of the CO2 and solar radiation. If these melt then there will be nothing to reflect the harmful radiation and to absorb CO2 . Effects of energy transfer
  33. 33. By : Mariam, Sohum, Sarah, Teyyab.