caused by the weight of the atmosphere. At sea level it has a mean value of one atmosphere but reduces with increasing altitude.
Ability of a surface to reflect light.
Distance above sea level.
Dry. A desert or other area with an arid climate has little precipitation
The whole mass of air surrounding the earth.
Terrestrial regions inhabited by certain types of life, especially vegetation. Examples are various types of deserts, grasslands, and forests.
Zone of earth where life is found. It consists of parts of the atmosphere (the troposphere), hydrosphere (mostly surface water and groundwater), and lithosphere (mostly soil and surface rocks and sediments on the bottoms of oceans and other bodies of water) where life is found. Sometimes called the ecosphere.
Physical properties of the troposphere of an area based on analysis of its weather records over a long period (at least 30 years). The two main factors determining an area’s climate are temperature, with its seasonal variations, and the amount and distribution of precipitation.
Leading edge of an advancing mass of cold air
Tiny particles on which droplets of water vapor can collect.
The temperature at which air becomes saturated and produces dew
A region of the ocean near the equator, characterized by calms, light winds, or squalls.
Distance above sea level.
The boundary between two air masses with different temperatures and densities.
A natural effect that releases heat in the atmosphere (troposphere) near the earth’s surface. Water vapor, carbon dioxide, ozone, and several other gases in the lower atmosphere (troposphere) absorb some of the infrared radiation (heat) radiated by the earth’s surface. This causes their molecules to vibrate and transform the absorbed energy into longer-wavelength infrared radiation (heat) in the troposphere. If the atmospheric concentrations of these greenhouse gases rise and they are not removed by other natural processes, the average temperature of the lower atmosphere will increase gradually.
Gases in the earth’s lower atmosphere (troposphere) that cause the greenhouse effect. Examples are carbon dioxide, chlorofluorocarbons, ozone, methane, water vapor, and nitrous oxide.
An air mass with a high pressure.
A severe tropical cyclone having winds greater than 64 knots (74 miles per hour; 119 kilometers per hour), originating in the equatorial regions of the Atlantic Ocean or Caribbean Sea or eastern regions of the Pacific Ocean, traveling north, northwest, or northeast from its point of origin, and usually involving heavy rains.
A high-speed, meandering wind current, generally moving from a westerly direction at speeds often exceeding 400 kilometers (250 miles) per hour at altitudes of 10 to 15 kilometers
Distance from the equator.
An air mass with a low pressure.
The portion of the atmosphere from about 30 to 80 kilometers (20 to 50 miles) above the earth’s surface, characterized by temperatures that decrease from 10;C to ;90;C (50;F to ;130;F) with increasing altitude.
Periods of heavy rains experienced on continents lying north or south of warm oceans.
The wind direction most frequently observed during a given period; the periods most often used are the observational day, month, season, and year. surface winds
rain shadow effect
Low precipitation on the far side (leeward side) of a mountain when prevailing winds flow up and over a high mountain or range of high mountains. This creates semiarid and arid conditions on the leeward side of a high mountain range.
Second layer of the atmosphere, extending about 17[[endash]]48 kilometers (11[[endash]]30 miles) above the earth’s surface. It contains small amounts of gaseous ozone (O3), which filters out about 95% of the incoming harmful ultraviolet (UV) radiation emitted by the sun.
The outermost shell of the atmosphere, between the mesosphere and outer space, where temperatures increase steadily with altitude.
A rotating column of air ranging in width from a few yards to more than a mile and whirling at destructively high speeds, usually accompanied by a funnel-shaped downward extension of a cumulonimbus cloud.
Innermost layer of the atmosphere. It contains about 75% of the mass of earth’s air and extends about 17 kilometers (11 miles) above sea level. Compare stratosphere.
A violent storm originating over tropical or subtropical waters, characterized by violent rainstorms and high-velocity cyclonic winds.
A tropical cyclone occurring in the western Pacific or Indian oceans.
;process in which cold, often nutrient-rich waters from the ocean depths rise to the surface.
The boundary between an advancing warm air mass and the cooler one it is replacing. Because warm air is less dense than cool air, an advancing warm front rises over a mass of cool air.
Short-term changes in the temperature, barometric pressure, humidity, precipitation, sunshine, cloud cover, wind direction and speed, and other conditions in the troposphere at a given place and time.