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The tropopause is defined as the lowest level at which the lapse rate decreases to 2°C/km or less, provided that the average lapse-rate, between that level and all other higher levels within 2.0 km does not exceed 2°C/km. [1] The tropopause is a first-order discontinuity surface, in which temperature as a function of height varies ...
Atop the troposphere is the tropopause, which is the functional atmospheric border that demarcates the troposphere from the stratosphere. As such, because the tropopause is an inversion layer in which air-temperature increases with altitude, the temperature of the tropopause remains constant. [2] The layer has the largest concentration of nitrogen.
Inside the troposphere, the temperature drops approximately linearly at a rate of 6.5 Celsius degrees per km, from a global mean of 288 Kelvin (15 Celsius) on the ground to 220 K (-53 Celsius). At higher altitudes, up to 20 km, the temperature is approximately constant; this layer is called the tropopause.
The troposphere is the lowest of the four layers and extends from the surface of the Earth to about 11 km (6.8 mi) into the atmosphere, where the tropopause (the boundary between the troposphere stratosphere) is located. The width of the troposphere can vary depending on latitude: for example, the troposphere is thicker in the tropics (about 16 ...
The layer closest to the Earth's surface is known as the troposphere. It extends from sea-level to a height of about 18 km (11 mi) and contains about 80 percent of the mass of the overall atmosphere. It extends from sea-level to a height of about 18 km (11 mi) and contains about 80 percent of the mass of the overall atmosphere.
The division of the atmosphere into layers mostly by reference to temperature is discussed above. Temperature decreases with altitude starting at sea level, but variations in this trend begin above 11 km, where the temperature stabilizes over a large vertical distance through the rest of the troposphere.
It varies with the temperature and pressure of the parcel and is often in the range 3.6 to 9.2 °C/km (2 to 5 °F/1000 ft), as obtained from the International Civil Aviation Organization (ICAO). The environmental lapse rate is the decrease in temperature of air with altitude for a specific time and place (see below). It can be highly variable ...
The atmosphere is warm at the surface and lower levels of the troposphere where there is mixing (the planetary boundary layer (PBL)), but becomes substantially cooler with height. The temperature profile of the atmosphere, the change in temperature, the degree that it cools with height, is the lapse rate .