Moisture precipitates out of the atmosphere primarily as three types of rain: convective, stratiform and orographic. In each case, warm, moist air is lifted up and suspended until it reaches saturation and then discharges its water content as rain.Know More
Convective rain is the simplest form, and it occurs mainly in tropical regions. In a convection system, water evaporates off of ocean and lake surfaces, rises through the air by simple convection and falls when the air is saturated. Convective fronts are usually localized and limited in their horizontal extent.
Stratiform rain results when a moist warm front encounters cooler, drier air. The cool air is denser than the warm front, so it subducts under the warm air and drives it to a higher altitude. Then, if conditions are right for precipitation, the warm mass discharges.
Orographic rain is driven by a process very similar to stratiform rain, but with the rain-laden clouds rising against mountains rather than sliding over cool air. A typical orographic rain begins over the ocean as a convection cell, moves toward land and is suddenly lifted high by a coastal range of mountains. Orographic systems usually drop their moisture soon after making landfall and rarely have the energy to penetrate deep inland. This deprives inland areas of rain and creates rain shadow deserts such as the Atacama.Learn more about Atmosphere
The thermosphere is the hottest layer of the atmosphere. It extends from 80 kilometers above the surface of the Earth up to 600 kilometers and can heat up to 1,500 degrees Celsius because it’s very sensitive to solar activity. The air is thin and extremely hot, and there are sparse air molecules in this layer.Full Answer >
Earth's atmosphere is primarily composed of nitrogen and oxygen with water vapor comprising 0.25 percent of the atmosphere by mass. It has five layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere.Full Answer >
Oxygen began to accumulate in the atmosphere during the Proterozoic Era, which began about two billion years ago and ended about 700 million years ago. Much of this oxygen arose from the actions of the cyanobacteria.Full Answer >
As the highest layer of the atmosphere, the Earth's exosphere contains very thin air and features both lower and upper boundaries. The exosphere's boundaries vary by altitude depending on the level of the sun's activity and solar radiation emissions. There is some debate among scientists as to whether the exosphere should be considered a layer of the atmosphere or a part of space.Full Answer >