Composition

• Nitrogen - 78%

  • Fundamental for living organisms. Deposits through nitrogen fixation and reaction involving lightning and subsequent precipitins.

• Oxygen - 21%

  • Produced through photosynthesis

• Water Vapor - 0-4%

  • Large amounts near the equator, areas with low atmospheric water vapor are over deserts and polar areas.

• Carbon Dioxide - <<1%

  • Produced during cellular respiration, combustion of fossil fuels, and decay of organic matter. Required for photosynthesis.

• Methane - <<<1%

  • Contributes to the greenhouse effect.

• Nitrous Oxide - <<<1%

  • Contributor to the greenhouse effect. Single most important contributing substance reducing stratospheric ozone.

• Ozone - <<<1%’

  • Most found in the stratosphere. Absorbs UV Radiation.

Structure

• The atmosphere is split up into multiple layers.

• Troposphere

  • Weather occurs in this zone.

  • 75% of atmospheric mass is in this zone.

• Stratosphere

  • Temperature increases because of the UV radiation in this zone.

• Mesosphere

  • Coldest layer.

  • Ice Clouds occur here.

• Thermosphere

  • Molecules are converted into ions.

  • Gamma Rays, X-Rays, UV radiation make the temperature rise.

Weather and Climate

• Weather

  • Caused by the movement or transfer of heat which causes unequal heating of the earth’s surface.

• Climate

  • Describes the total of all weather occurring over a period of years.

• Radiation

  • The flow of electromagnetic radiation. It is how the Earth receives solar energy.

• Conduction

  • Transfer of heat through solid substances.

  • Causes a difference in temperature between different parts of the substance.

• Convection

  • The movement of warmer molecules in the air.

  • Primary way energy is transferred from hotter to colder regions in the Earth’s atmosphere. Determines weather patterns.

• Factors that influence the climate

  • Air Mass

  • Albedo (Reflectivity)

  • Altitude

  • Angle of Sunlight

  • Carbon Cycle

  • Clouds

  • Distance to Ocean

  • Fronts

  • Greenhouse Effect

  • Human Activity

  • Land Changes

  • Landmass Distribution

  • Latitude

  • Location

  • Mountain Ranges

  • Pollution

  • Precession

  • Rotation

  • Solar Output

  • Volcanoes

  • Wind Patterns

Atmospheric Circulation - Pressure

• Air closest to the Earth’s surface is warmer and rises.

• Air higher up in the atmosphere is colder and will sink.

• Low-Pressure System

  • Low Pressure at the center.

  • Winds blow towards the low pressure.

  • Usually forms clouds and precipitation.

  • Produces cloudy and stormy weather.

• High-Pressure System

  • Wind blows away from the high pressure.

  • Contain cool, dense air.

  • Usually associated with fair weather.

• Coriolis Effect

  • Earth’s rotation on an axis causes winds to not travel straight.

• Hadley, Ferrel, and Polar Cells

  • The worldwide system of winds.

• Hadley Air Circulation Cells

  • Air heated near the equator rises and spreads out north and south.

  • After cooling in the upper atmosphere, the air sinks back down to the subtropical climate zone.

• Ferrel Air Circulation Cells

  • Develop between 30 degrees and 60 degrees north and south latitudes.

  • Area where these circulation cells control contains broadleaf, deciduous, and coniferous evergreen forests.

• Polar Air Circulation Cells

  • Icy-cold, dry, dense air that descends from the troposphere to the ground.

  • Air meets with warm tropical air and then returns to the poles.

  • Reason why polar areas are deserts.

• Polar Vortex

  • Low-Pressure zone that lies above both poles.

  • Large Mass of Cold Air.

Hurricanes, Tornadoes, and Cyclones

• Hurricanes

  • Most severe weather phenomenon on the planet.

  • Warm areas over oceans where the trade winds converge.

  • Separate thunderstorms move in a circular motion. It allows them to pick up moisture and heat energy from the ocean.

  • Energy from the hurricane dissipates over land.

• Tornadoes

  • Swirling masses of air.

• Tornadoes vs Cyclones

  • Tornadoes are caused by a singular storm.

  • Cyclones are developed from multiple separate storms.

  • Tornadoes are over land.

  • Tropical Cyclones die out over land due to the lack of moisture.

• Monsoons

  • Strong, violent winds that change direction with the season.

  • Blows from cold to warm regions.

El Niño - Southern Oscillation

• La Nina

  • Normal Conditions

  • Easterly Trade Winds move water and air warmed by the sun towards the west.

  • Water in the Pacific is 14 degrees hotter.

• El Nino (Warm Phase)

  • Air pressure reverses direction.

  • Causes extensive fish kills due to water moving away.

  • Ocean temperatures are their warmest.

  • Enhances convection.

• El Nino (December - February)

  • Surface water returns to cooler, nutrient-rich water.

  • Supplies necessary nutrients to phytoplankton.

• La Nina (Cold Phase)

  • Trade winds that blow west are stronger than usual.

  • Leads to wetter than normal conditions across the Pacific Northwest, and drier weather in the Southern United States.

  • Winter temperatures are warmer in the Southern United States and cooler in the northwest.

  • Causes heavier monsoons in Southeast Asia and India.