Energy in the Atmosphere Energy from the sun travels to Earth as electromagnetic waves – mostly visible light, infrared radiation (longer wavelengths) and ultraviolet radiation (shorter wavelengths) Energy from the sun travels to Earth as electromagnetic waves – mostly visible light, infrared radiation (longer wavelengths) and ultraviolet radiation (shorter wavelengths) When Earth’s surface is heated, it radiates some of the energy back into the atmosphere in the form of longer-wavelength radiation When Earth’s surface is heated, it radiates some of the energy back into the atmosphere in the form of longer-wavelength radiation

Energy in the Atmosphere Electromagnetic waves Electromagnetic waves a form of energy that can travel through space a form of energy that can travel through space Radiation Radiation the direct transfer of energy through empty space by electromagnetic waves the direct transfer of energy through empty space by electromagnetic waves Scattering Scattering reflection of light in all directions reflection of light in all directions Greenhouse effect Greenhouse effect the process by which heat is trapped in the atmosphere by water vapor, carbon dioxide, methane, and other gases that form a “blanket” around the Earth the process by which heat is trapped in the atmosphere by water vapor, carbon dioxide, methane, and other gases that form a “blanket” around the Earth

Heat Transfer Temperature of the air is typically measured with a thermometer Temperature of the air is typically measured with a thermometer Three forms of heat transfer – radiation, conduction, and convection – work together to heat the troposphere Three forms of heat transfer – radiation, conduction, and convection – work together to heat the troposphere

Heat Transfer Thermal energy Thermal energy The total energy of a substance’s particles due to their movement or vibration The total energy of a substance’s particles due to their movement or vibration Temperature Temperature The average amount of energy of motion in the molecules of a substance The average amount of energy of motion in the molecules of a substance Heat Heat The movement of thermal energy from one substance to another The movement of thermal energy from one substance to another Conduction Conduction The transfer of heat by movements of a fluid (liquids and gases) The transfer of heat by movements of a fluid (liquids and gases) Convection Convection The transfer of heat by movement of currents within a fluid (liquids and gases) The transfer of heat by movement of currents within a fluid (liquids and gases)

Winds All winds are caused by differences in air pressure, which are the result of unequal heating of Earth’s surface All winds are caused by differences in air pressure, which are the result of unequal heating of Earth’s surface Local winds are caused by unequal heating of Earth’s surface within a small area Local winds are caused by unequal heating of Earth’s surface within a small area The movement of air between the equator and the poles produces global winds The movement of air between the equator and the poles produces global winds

Winds Wind Wind The horizontal movement of air from an area of high pressure to an area of lower pressure The horizontal movement of air from an area of high pressure to an area of lower pressure Anemometer Anemometer An instrument used to measure wind speed An instrument used to measure wind speed Wind-chill factor Wind-chill factor Increased cooling caused by the wind Increased cooling caused by the wind Sea breeze Sea breeze The flow of air from an ocean or lake to the land The flow of air from an ocean or lake to the land Land breeze Land breeze The flow of air from land to a body of water The flow of air from land to a body of water

WindsMonsoon Sea and land breezes over a large region that change directions with the seasons Sea and land breezes over a large region that change directions with the seasons Coriolis effect Coriolis effect The way Earth’s rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left The way Earth’s rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left Latitude Latitude The distance north or south from the equator, measured in degrees The distance north or south from the equator, measured in degrees Jet stream Jet stream Bands of high-speed winds about 10 km above the Earth’s surface Bands of high-speed winds about 10 km above the Earth’s surface

Water in the Atmosphere Relative humidity is the percentage of water vapor in the air compared to the amount of water vapor the air could hold. It can be measured with a psychrometer. Relative humidity is the percentage of water vapor in the air compared to the amount of water vapor the air could hold. It can be measured with a psychrometer. Clouds of all kinds form when water vapor in the air becomes liquid water or solid ice. Clouds of all kinds form when water vapor in the air becomes liquid water or solid ice. Meteorologists classify clouds into three main types: cumulus, stratus and cirrus. Meteorologists classify clouds into three main types: cumulus, stratus and cirrus.

Water in the Atmosphere Evaporation Evaporation The process that occurs when vaporization takes place only on the surface of a liquid The process that occurs when vaporization takes place only on the surface of a liquid Humidity Humidity A measure of the amount of water vapor in the air A measure of the amount of water vapor in the air Relative humidity Relative humidity The percentage of water vapor in the air compared to the maximum amount the air can hold at that temperature The percentage of water vapor in the air compared to the maximum amount the air can hold at that temperature Psychrometer Psychrometer An instrument used to measure relative humidity, consisting of a wet- and dry-bulb thermometer An instrument used to measure relative humidity, consisting of a wet- and dry-bulb thermometer

Water in the Atmosphere Condensation The process by which a gas (water vapor) changes to a liquid (water) The process by which a gas (water vapor) changes to a liquid (water) Dew point Dew point The temperature at which condensation begins The temperature at which condensation begins Cumulus Cumulus Clouds that form less than 2 km above the ground and look like fluffy, rounded piles of cotton Clouds that form less than 2 km above the ground and look like fluffy, rounded piles of cotton Stratus Stratus Clouds that form in flat layers Clouds that form in flat layers Cirrus Cirrus Wispy, feathery clouds made of mostly ice crystals that form at high levels, above about 6 km Wispy, feathery clouds made of mostly ice crystals that form at high levels, above about 6 km

Precipitation Common types of precipitation include rain, sleet, freezing rain, hail and snow. Common types of precipitation include rain, sleet, freezing rain, hail and snow. Rain is measured with a rain gauge. Rain is measured with a rain gauge. Scientists have used cloud seeding to produce rain and to clear fog from airports. Scientists have used cloud seeding to produce rain and to clear fog from airports.

Precipitation Precipitation Precipitation Forms of water such as rain, snow, sleet or hail that fall from clouds and reach Earth’s surface Forms of water such as rain, snow, sleet or hail that fall from clouds and reach Earth’s surface Rain gauge Rain gauge An instrument used to measure the amount of precipitation, consisting of an open-ended container topped by a collecting funnel and having a collecting tube and measuring scale inside An instrument used to measure the amount of precipitation, consisting of an open-ended container topped by a collecting funnel and having a collecting tube and measuring scale inside Drought Drought A water shortage caused by long periods of low precipitation in a particular area A water shortage caused by long periods of low precipitation in a particular area