Atmosphere Layers PDF

The Atmosphere https://www.cbsnews.com/news/trump-greenland-panama-canal-why-us-interest/ https://www.cbc.ca/news/canada/nova-scotia/climate-change-eliminating-sea-ice-in-gulf-of-st-lawrence-1.7402408 Weather is the instantaneous picture of atmospheric conditions for a given pla...

The Atmosphere https://www.cbsnews.com/news/trump-greenland-panama-canal-why-us-interest/ https://www.cbc.ca/news/canada/nova-scotia/climate-change-eliminating-sea-ice-in-gulf-of-st-lawrence-1.7402408 Weather is the instantaneous picture of atmospheric conditions for a given place at a given time. Weather is constantly changing. What is the weather right now? Wait 5 minutes the weather will change… A weather event… Climate is the long-term average of a set of atmospheric conditions for a given region…(climate normals: 1971-2000). Climate is constantly changing. What is the climate of Bermuda, compared to Saskatoon? Examples of climate-types: Arctic, continental, tropical, desert…  Climate normals (1991- 2020) for January for Saskatoon, SK https://climate.weather.gc.ca/climate_normals/results_1991_2020_e.html?searchType=stnName_1991& txtStationName_1991=Saskatoon&searchMethod=contains&txtCentralLatMin=0&txtCentralLatSec=0&tx tCentralLongMin=0&txtCentralLongSec=0&stnID=265000000&dispBack=1 The Atmosphere The Atmosphere Cloud of gas and suspended solids extending from the Earth's surface to 1000s km above the surface. Becomes thinner with elevation but always held by the Earth's gravitational pull. 97% of the atmosphere lies within 30 km of the surface. Has no defined ending – it fizzes out.  The atmosphere Is composed of 2 types of gases: Permanent gases - (homogeneously mixed) Variable gases - (heterogeneously mixed) The permanent gases Include N2 (78%) and O2 (21%) …and argon (~1%). Their proportion in the atmosphere never really changes. Because they have a long residence time, these gases are in equilibrium. These gases don’t change and so are not extremely important for change. The variable gases Variable gases (H2O, CO2, O3, CH4). Gases whose composition changes due to volcanic activity and anthropogenic activities. Most of these gases are greenhouse gases, and extremely important for weather and climate changes. Relatively short residence time. Mount St-Helens, May 18th, 1980  Ashcloud over Mt. Pinatubo Mount Pinatubo (June 15th 1991) The year without a summer Tambora, Indonesia, eruption in 1815. Largest eruption in recorded history. Even felt by aboriginal people in northern Labrador.  Variable gases - (less than 1% in total) 1. Water vapour 2. Carbon dioxide 3. Ozone 4. Methane 11. Water vapour The gas phase of water. Condensation of water vapour to liquid or ice is responsible for clouds, rain, snow, and other precipitation. All of which count among the most significant elements of what we experience as weather. Concentration in the atmosphere changes in time and place. Absorbs solar energy very well. 22. Carbon dioxide Sources are natural and anthropogenic. - Natural Respiration, decay of organic material, volcanic activity and natural combustions. - Anthropogenic Combustion CO2 absorbs solar energy. https://gml.noaa.gov/ccgg/trends/ https://gml.noaa.gov/ccgg/trends/ 33. Ozone A layer of O3 molecules in the stratosphere. Absorbs ultraviolet radiation from the sun. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.temis.nl%2Fprotocols%2FO3global.php&psig=AOvVaw3MpyF89hy5IK4- g2Hpc-A_&ust=1736475587228000&source=images&cd=vfe&opi=89978449&ved=0CBQQjRxqFwoTCMCD6YTK54oDFQAAAAAdAAAAABAE 44. Methane CH4 Absorbs solar radiation. Sources also include: -Rice agriculture (or anywhere you have water logged conditions). -landfills. -fossil fuel combustion. -wastewater treatment. Aerosols (particulates) Solids and liquid particles in the air (soot, sea salts, etc.). Plays an important role in the formation of clouds and precipitation. Can cause solar dimming. https://wcscanada.org/our-work/wild-places/peatlands/ Atmosphere layers The Atmosphere … is made up of layers  Layers of the atmosphere Six defined “spheres” make up the atmosphere. Four of them are defined by their thermal characteristics (similar temperature characteristics throughout the air body). There are also two “others”.  Troposphere + stratosphere = lower atmosphere Mesosphere + thermosphere = upper atmosphere  Atmospheric Structure The layers are generally defined by temperature: In some layers, temperature decreases with altitude, in others, it increases with altitude. At each layer, the thermal characteristics are due to different properties.  Layers of the atmosphere (not to scale) Layers of the atmosphere The chemical atmosphere lasts until about 80 km above the earth’s surface. - This zone is called the homosphere (or homogeneously mixed). - Beyond 80 km is the heterosphere where gases are not evenly mixed. Troposphere Layer closest to earth. Zone of life and zone of weather. Where the troposphere ends the temperature is ~ -57°C. Zone where temperature decreases with altitude: Decrease on average of about - 6.5°C/kmm  Troposphere The depth of the troposphere changes according to season and varies in thickness from equator to the poles. Temperature decreases with height because heat comes from the earth’s surface.  Troposphere Contains most of the water droplets and dust particles in the atmosphere.  Stratosphere Extends from ~15 km to ~50 km above the surface of the earth. T °increases with increasing altitude above the surface of the earth. T°is ~-57°C at the tropopause to ~-2°C at the stratopause. T° increases because the ozone layer absorbs a large amount of UV energy in the stratosphere.  Ozone layer Between 20-30 km thick. It is a component of the stratosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 97-99% of the sun’s high frequency UV light, which is potentially damaging to life on earth. In higher layers of the atmosphere, ozone is a good thing as it breaks down incoming UV radiation...in the troposphere, it is not so good. Mesosphere Temperature again declines in this zone. Temperature reaches about - 90 °C at ~ 80 km. Thermosphere Zone has a very low density of any gas.  The Others… Ionosphere Defined by electrical properties (not temperature). It is made up of ions, which are formed when atoms or molecules lose electrons. Electrons are lost due to incoming solar energy. Aurora borealis (northern lights) Aurora australis (southern lights) The Earth has a magnetic properties deep within its core. The magnetic field lines go into and out of the Earth around the magnetic poles. Where the lines are closest together the field is strongest. Subatomic particles from the sun are captured by the earth’s magnetic field. These particles become excited when they contact the atmosphere, and they release energy.  Ionosphere layers Made up of layers of electrically charged ions. Depending on the time of day, these different layers can enhance or harm other waves such as AM radio waves. https://www.aeronomie.be/sites/default/files/2022-11/Ionosphere-layers-height-en.png Exosphere Zone has a very low density of any gas. From about 600 to 10,000 km above earth’s surface. Satellites live there. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQBYqLx9p9Ad0-DqhibO6qLEVVTYIRVKP5v3Q&s Summary for today The atmosphere acts like a blanket around the earth. This ‘blanket’ is filled with permanent and variable gases, which decrease in density with elevation above the earth. Most of the variable gases absorb solar energy. The atmosphere can be divided into layers based on temperature. The ionosphere is defined by its electrical properties, while the exosphere is just way out there.