Chapter 8: Atmosphere Lesson 1 Atmospheric Basics

Atmospheric Composition:

  • Permanent Atmospheric Gases:

    • 99% of the Atmosphere is composed of Nitrogen and Oxygen

    • Last 1% consists of Argon, Carbon Dioxide, Water Vapor, and Other Trace Gases

  • Variable Atmospheric Gases:

    • Concentration of some atmospheric gases are not constant over time

      • Ex. Carbon Dioxide, Water Vapor, and Ozone

  • Water Vapor: Invisible gaseous form of water

    • Amount of water vapor in air over a desert v/s a rain forest

    • Varies with seasons, altitude of body of air, and properties off surface of Ozone

  • Ozone:

    • Has the chemical formula of O3

    • Varies seasonally at higher latitudes, reaching a minimum during the spring

  • Carbon Dioxide:

    • Has increased over the last 150 years

      • Increase is primarily because of fossil fuels

  • Atmosphere Particles:

    • Atmosphere contains variable amount of solids in the form of dust, salt and ice

    • Particles are picked up and transported by the wind

  • Atmospheric Layers

    • Atmosphere is broken into 5 distinct layers

  • Troposphere:

    • Contains most of the muns of the atmosphere

    • Where weather occurs

    • Colder as you go up

    • Contains 99% of all Water Vapor

  • Stratosphere:

    • Temperatures increases as you go up

    • 99.9% of the mass of Earth’s atmosphere is below the stratopause

    • Home of Ozone layer

    • Dry and Cloud Free

    • Where planes fly

  • Mesosphere:

    • Temp. decreases as you go up

    • About 50-85 km above Earth’s surface

    • Temp. decrease is from little absorption of solar radiation

    • Earth’s meteor shield

  • Thermosphere:

    • Home of the Northern lights

    • Between 85-600 km above Earth’s surface

    • High absorption of solar radiation so it has high temps

    • Space stations’ home

    • Contains ionosphere which is made of electronically charged particles

  • Exosphere:

    • Outermost layer of Earth’s atmosphere

    • Extends from 600-10000 km above Earth’s surface

    • Transitional area between the atmosphere and outer space

  • Energy Transfer in the Atmosphere:

    •  All materials are made of particles, such as atoms and molecules

    • Particles are always moving, even if the object they make up is not

    • A moving object has a form of energy called kinetic energy

    • The total energy of the particles in an object, due to their random motion, is called thermal energy

    • Heat is a transfer of thermal energy (higher to lower), and are transferred by radiation, convection, and conduction

  • Radiation:

    • Transfer of thermal energy by electromagnetic waves

    • Solar Radiation that reaches Earth is absorbed and reflected by the atmosphere and Earth’s surface Absorption and Reflected

  • Absorption and Reflection

    • Most solar energy reaches Earth in the form of visible light and infrared waves

  • Rate of Absorption:

    • Depends on the physical characteristics of the area and amount of solar radiation it receives

  • Conduction: Transfer of thermal energy between objects when their atoms or molecules collide (objects are in contact)

    • Conduction occurs more easily in solids and liquids than than in gases

  • Convection: Transfer of thermal energy from one place to another

    • Process generally occurs in liquids and gases

  • How the Atmosphere Refrains Heat:

    • Greenhouse Effect: the natural heating of Earth’s surface caused by certain atmospheric gases called greenhouse gases

      • Gases include: water vapor, methane, and carbon dioxide