The Earth's Atmosphere

Earth's Atmosphere

Overview

  • Earth's atmosphere is a gaseous layer surrounding the planet.

  • Comprised of several layers, each with distinct characteristics and functions.

Composition of Earth's Atmosphere

  • Main Components:

    • Nitrogen: 78%

    • Oxygen: 21%

    • Argon: 0.9%

    • Carbon Dioxide (CO2): 0.04%

  • Extends 8-15 kilometers (5-9 miles) high.

Troposphere

  • Lowest layer of the atmosphere, a gaseous layer

  • Almost all weather occurs here; contains 99% of the atmosphere's water vapor.

  • Air circulation patterns influence weather.

  • Temperature decreases with altitude.

Tropopause

  • Transition zone between the troposphere and stratosphere.

Stratosphere

  • Second atmospheric layer, from 8-15 km to ~50 km high.

  • Contains the ozone layer, which absorbs UV radiation.

  • Temperature increases with altitude.

  • Less air circulation but winds that occur in the lowerstratosphere, impacting weather patterns and aviatio

Stratopause

  • Boundary between the stratosphere and mesosphere.

Mesosphere

  • Extends from 50 km to ~85 km high, where temperature decreases.

  • Coldest layer; most meteorites burn up here. (-90C or -130F)

Mesopause

  • Coldest point in the atmosphere; boundary between mesosphere and thermosphere.

Thermosphere

  • Extends from 80 km to 550 km high.

  • Temperature increases dramatically. (2500C/4500F or higher)

  • Incredibly thin air despite high temperatures, low density; site of auroras (due to solar wind interacting with magnetic field)

  • Plays a key role in absorption of high-energy ultraviolet and X-ray radiation

Exosphere

  • Outermost layer, from 550 km to 10,000 km high.

  • No boundary

  • Contains sparse particles, mainly hydrogen and helium.

  • Satellites (geostationary satellites) orbit in this layer; particles can escape into space.

  • Incredibly thin and low in density

Greenhouse Effect

  • Process where certain gases trap heat in the atmosphere.

  • Involves sunlight, Earth's radiation, and the trapping of heat by gases like CO2 ,methane and water vapor

Greenhouse Gases

  • Key Gases:

    • Carbon Dioxide (CO2): From burning fossil fuels.

    • Methane (CH4): From agriculture and livestock.

    • Water Vapor (H2O): Naturally occurring but increased by humans.

    • Nitrous Oxide (N2O): From industrial practices and fertilizers.

      • Potent GHG, 298 times global warming potential of CO2 over a 100 yr period.

    Due to human activity, more gases are released.

  • How to Mitigate

    • Reduce fossil fuel consumption (renewable energy)

    • Improve energy efficiency.

    • Plant trees and protect forests to absorb CO₂.

    • Transition to sustainable agricultural practices

Stratospheric Ozone

  • Ozone (O3) is a molecule made up of three oxygen atoms

  • Found in stratosphere

  • Contains highest concentration of ozone and acts as a protective shield for the Earth.

  • Threats: Chlorofluorocarbons(CFC’s), Ozone Hole, Ozone- Depleting substances.

Protecting the Atmosphere

  • Montreal Protocol (1987): global agreement to phase out use of ozone-depleting chemicals.

  • Ozone Monitoring: Satellite and ground-based observations, track ozone levels, helping scientists assess recovery.

  • Positive trends: Ozone levels are slowly recovering due to the reduction of ODS, with full recovery expected around the middle of the 21st century if current efforts continue

Global Warming

  • Refers to the long-term increase in Earth’s average surface temperature due to human activities.

  • Increased levels of greenhouse gases (GHGs) likecarbon dioxide (CO₂), methane (CH₄), and nitrousoxide (N₂O) trap heat in the atmosphere, leading to higher global temperatures.

  • Cause: Burning Fossil Fuels, Deforestation, Agriculture & Waste emit methan and nitrous oxide

  • Impacts: Rising temperatures, Melting Ice Caps, Extreme Weather, Ecosystem Disruption

Solutions for Global Warming

  • Reduce Carbon Emissions: shift to renewable energy sources(solar, wind, hydroelectric) and improve energy efficiency

  • Reforestation and Afforestation: plant trees to absorb CO₂ andrestore degraded ecosystems

  • Sustainable Agriculture: Implement sustainable farmingpractices, reduce food waste, and minimize emissions fromlivestock

  • Public Awareness and Action: Reduce individual carbonfootprints through actions like using public transport, reducingwaste, and supporting policies that tackle climate change.

Climate Change

  • Long-term shifts in temperature and precipitation patterns, and other atmospheric conditions on Earth due to human activities.

  • Key causes: greenhouse gas emissions, deforestation, industrial practices.

  • Impacts: Melting glaciers, extreme weather, threats to ecosystems and human health. //tinamad na ko madami sila eh

  • Ways to help: Reducing carbon footprint, supporting sustainable businesses and practices

  • Advocating for policy change and green initiatives.

Acid Rain //kulang to btw

  • Results from sulfur dioxide and nitrogen oxides causing precipitation to be acidic.

  • Two deposition types: wet deposition and dry deposition

  • Wet precipitation: common form of wet deposition is rain (sulfuring and nitric acis mix with water droplets, creating acidic soln)

  • Dry precipitiation: sulfur and nitrogen oxides are released; pollutants can remain suspended in the atmosphere for a short period of time, being carried by wind and air currents. They travel through the air.

    • Gravtitaional Settling - gravity pulls heavier particles to the surface

    • Turbulent Diffusion - smaller particles and gases move through air. More common for fine particulate matter or gaseous pollutants

    • Brownian Motion: Very small particles (nanoparticles); random motion due to collisions of air molecules