Layers of the Atmosphere & Heat Transfer
What is the troposphere?
- Closest to earth's surface - All important weather phenomena occur here - Convection currents within the air occur in this layer - The temperature decreases as altitude increases - Air is heated from the energy radiated from the Earth's surface, sunlight warms the ground or ocean, which in turn radiates the heat into the air right above it - Since most of the heat is found near Earth's surface, the farther you are from the surface the less heat there will be - The air temperature stops decreasing at the 12km mark
Why is the Earth divided into four main layers?
- Earth's atmosphere has a distinctive pattern of temperature changes with increasing altitude. - The temperature changes mainly because of how solar energy is absorbed as it moves downward through the atmosphere. - The four main layers can be described through these temperature changes.
What is convection?
- Energy (heat) that is transferred by currents within fluids or gases.
What is conduction?
- Energy (heat) that is transferred by direct contact.
What is radiation?
- Energy (heat) that is transferred by electromagnetic waves. - Radiation travels out in all directions from it's source Radiation does NOT require matter to transfer thermal energy
What is the mesosphere?
- Extends 80km above the Earth's surface - Temperature decreases as altitude increases - Coldest layer of our atmosphere with temperatures reaching nearly -90ºC - Layer where many meteors burn up when they enter the earth's atmosphere - Scientists know less about the mesosphere than other layers of the atmosphere because we do not have many ways to get scientific instruments to take measurements here, making it very hard for scientists to study
What is the stratosphere?
- Extends nearly 50km above the Earth's surface - The ozone layer can be found in the layer half of the stratosphere - The ozone absorbs incoming ultraviolet radiation from the sun -> the temperatures in the stratosphere increase with altitude - There is very little water vapor found in this layer -> few clouds are found in this layer - Convection does not occur in this layer -> there is little turbulence here, which is why commercial aircrafts fly in the lower stratosphere instead of the troposphere. - Materials that get into the stratosphere are able to stay there for a long period of time since there is little to no convection
What are the two sub- layers is the thermosphere (in order to closest to Earth)?
- Ionosphere - Exosphere
What is the Exosphere?
- Make up upper portion of the thermosphere - Marks the line between earth's atmosphere and interplanetary spacer - Satellites orbit the earth
What is the Ionosphere?
- Makes up lower portion of thermosphere - Gas molecules are electrically charges due to sun's energy - Radio waves bounce back from this layer to Earth's surface (making radio communication possible) Auroras occur
What are the three boundaries separating the four layers (in order form farthest from the Earth to closest)?
- Mesopause - Stratopause - Tropopause
What is the thermosphere?
- The last layer of our atmosphere - Extends from the end of the Mesosphere -> beginning of outer space - Has no well-defined upper limit - Temperatures increase with altitude in this layer because atomic oxygen and nitrogen absorb short-wave, high energy solar radiation - It is divided into two sub- layers: the exosphere and ionosphere
What are the four layers of the atmosphere (in order form farthest from the Earth to closest)?
- Thermosphere - Mesosphere - Stratosphere - Troposphere
What is thermal energy transfer?
Heat that moves from a warmer object to a cooler object.
What does the mesopause separate?
Thermosphere & Mesosphere
What does the stratopause separate?
Mesosphere & Stratosphere
What does the tropopause separate?
Stratosphere & Troposphere
