Chapter 1: Earth's Atmosphere

Mid Term Review

Weather

The condition of the atmosphere at any particular time and place; constantly changing.

Elements of Weather

Temperature, Pressure, Humidity, Clouds, Precipitation, Visibility, Wind.

Climate

The accumulation of daily and seasonal weather events; average range of weather over a period of time.

Earth's early atmosphere

Made primarily of Hydrogen and Helium during the formation of the Earth.

Today's atmosphere composition

Nitrogen (78%), Oxygen (21%), and Argon (0.93%).

Dominant constant gases

Gases whose concentrations remain relatively stable over time and space in the atmosphere, making up the majority of it.

Dominant variable gases

Gases whose concentrations fluctuate over time and location due to natural and human activities, playing key roles in weather.

Most important variable gas for weather

Water vapor (H2O) is crucial for cloud formation, precipitation, and energy transfer in the atmosphere.

CO2 concentration change (last 150 years)

Increased significantly from 280 ppm to 420 ppm due to human activities.

Ozone

Found in the stratosphere and troposphere; protects from harmful UV radiation.

Good ozone

Absorbs harmful UV radiation from the Sun in the stratosphere.

Density

Mass per unit volume (kg/m^3), decreases with altitude due to spreading of air molecules.

Pressure

Force exerted by air molecules per unit area, measured in millibars or pascals.

Temperature

Measure of molecular kinetic energy, varies with altitude, affects weather and atmospheric circulation.

Troposphere

Lowest layer of the atmosphere containing 76% of its mass, where weather occurs.

Stratosphere

Layer above the troposphere (10-50 km) where temperature increases with height due to ozone.

Temperature in the troposphere

Decreases with height as Earth's surface heats the air below.

Temperature in the stratosphere

Increases with height due to ozone absorbing UV radiation.

Geostationary satellite

Orbits 36,000 km above the equator, staying fixed over one location for continuous weather monitoring.

Visible Satellite

Shows sunlight reflected by clouds and Earth's surface, useful for daytime cloud cover.

Infrared (IR) Satellite

Shows heat emitted by objects, best for night weather, cloud heights, and temperatures.

Water Vapor Satellite

Tracks moisture content in the atmosphere, jet streams, and storm development.

Meteorology

The scientific study of the atmosphere, focusing on weather processes and forecasting.

Middle Latitudes

Regions between 30° and 60° latitude, characterized by variable weather and distinct seasons.

Middle-Latitude Cyclonic Storm

Large, low-pressure system common in mid-latitudes with counterclockwise rotation.

Hurricane

Powerful tropical cyclone forming over warm ocean waters with sustained winds of 74 mph or higher.

Thunderstorms

Storms with lightning and heavy rain, caused by strong rising air currents.

Tornadoes

Violently rotating columns of air extending from thunderstorms to the ground.

Wind

Horizontal movement of air caused by differences in atmospheric pressure.

Wind Direction

The direction from which the wind is blowing, measured in degrees.

Wind Speed

Rate at which air moves past a point, measured in mph or m/s.

Front

A boundary between two air masses with different temperatures and densities.

Outgassing

Release of gases from Earth’s interior through volcanic eruptions.

Nitrogen

Constant gas making up ~78% of Earth's atmosphere, essential for life.

Oxygen

Constant gas composing ~21% of the atmosphere, vital for respiration.

Carbon Dioxide (CO₂)

Variable gas crucial for the greenhouse effect, currently rising due to human activities.

Ozone (O₃)

Molecule made of three oxygen atoms, protects from harmful UV radiation.

Aerosols

Tiny particles suspended in the atmosphere, affecting cloud formation and light scattering.

Pollutants

Harmful substances released into the atmosphere, degrading air quality.

Air Density

Mass of air per unit volume, influenced by temperature and pressure.

Air Pressure

Force exerted by the weight of air molecules, measured in millibars or inches of mercury.

Lapse Rate

The rate at which temperature decreases with altitude in the atmosphere.

Temperature Inversion

Situation where temperature increases with height, trapping pollutants.

Radiosonde

Instrument carried by a weather balloon to measure atmospheric temperature, pressure, and humidity.

Tropopause

Boundary between troposphere and stratosphere, where temperature stops decreasing with altitude.

Mesosphere

Layer above the stratosphere where temperature decreases with height.

Thermosphere

High-altitude layer with thin air and rising temperatures due to solar radiation absorption.

Ionosphere

Region within the thermosphere filled with ionized particles, important for radio wave transmission.