|The amount of water a certain volume of air holds. ||absolute humidity|
|The envelope of the gaseous mixture surrounding Earth.
|The force per unit area exerted by the atmosphere at a given location.
|The same phenomenon as aurora borealis, except it occurs in the southern hemisphere.
|The streamers or bands of light that appear in the sky of the Northern Hemisphere when high-energy charged particles from the magnetosphere collide with atmospheric molecules.
|The direct transfer of thermal energy through a substance or from one object in physical contact with another.
|A visible trail of condensed water vapor or ice crystals form in the wake of an aircraft.
|The indirect transfer of thermal energy from one place to another by the movement of currents of cooler, more dense matter into regions of warmer, less dense matter. Convection occurs in liquids and gases because their particles are mobile.
|The outermost zone of the earth's atmosphere that extends into space itself.
|the warming of the lower atmosphere by infrared radiation that is radiated by the earth's surface after it absorbs visible radiation from the sun.
|Any of the gases present in the atmosphere that enhance the absorption of infrared radiation by the atmosphere Water vapor, carbon dioxide, and several other naturally occurring gases are the predominant greenhouse gases.
|One of the zones of the atmosphere defined by composition. It is the collection of gas layers above the homosphere consisting of separate layers of oxygen, helium, and hydrogen.
|One of the zones of the atmosphere when it is subdivided by composition; the layer of the atmosphere nearest the earth's surface consisting of a homogeneous mixture of gases.
|An atom or molecule having a positive or negative charge. ||ion
|That portion of Earth's upper atmosphere where solar ultraviolet radiation breaks down the gas molecules into individual atoms and ions. It reflects shortwave radio signals. The zone is from about 70-80 km to 500 km or more above the Earth's surface.
|A high-speed meandering wind current, usually flowing from west to east at altitudes of 15-25 km. Its speed often exceeds 400 km/h.
|The rate at which temperature changes with altitude in the atmosphere. The average tropospheric lapse rate is -6.4 degrees Celsius/km.
|The magnetic field that encircles the earth and traps high-energy ions from the sun's solar wind. It protects living things from damage by the sun's particle radiation. ||magnetosphere|
|The upper boundary of the atmospheric mesosphere.
|One of the layers of the atmosphere defined by temperature profile. The zone of the earth's atmosphere between about 50-80 km above sea level, characterized by decreasing temperature with increasing altitude.
|The science of the earth's atmosphere, especially the weather.
|An optical phenomenon that the atmosphere produces because of the differing densities of hot and cool air and the way light travels through them.
|A colorless, odorless, tasteless gas that forms approximately 78% of the earth's atmosphere by volume.
|To provide a nucleus for moisture freezing, condensation, or sublimination.
|A colorless, tasteless, odorless gas that forms approximately 21% of the earth's atmosphere and is the essential element for respiration. It is the most abundant element in the earth's crust.
|A layer of concentrated ozone (O3) located 20-50 km above the earth's surface that shields the earth from the harmful forms of ultraviolet light. ||ozone layer|
|Moisture falling from the atmosphere as rain, hail, snow, or sleet. ||precipitation|
|A ratio of the amount of water the air is actually holding to the amount it could hold at that same temperature, expressed as a percentage.
|The upper boundary of the stratosphere, between the stratosphere and the mesosphere, about 50 km above the earth's surface.
|A region of the earth's atmosphere defined by the temperature profile located between the troposphere and the mesosphere and between 12-50 km above the earth's surface. The temperature increases with altitude through this region.
|The upper boundary of the thermosphere, approximately 200-500 km above sea level depending on solar activity.
|The highest and largest of the 4 atmospheric layers defined by temperature profile, ranging from about 80 km to 500 km above sea level. It is characterized by the highest daily temperatures in the atmosphere.
|The upper boundary of the troposphere that separates the troposphere from the stratosphere. ||tropopause|
|The lowest of the 4 layers of the earth's atmosphere defined by the temperature profile. It is the location of all weather that affects the earth's surface.
|The condition of the atmosphere at a given time. ||weather|
|The temperature of still air that would have the same effect on exposed human skin as a certain combination of air temperature and wind speed. ||wind-chill factor|