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Section T T index 501-509 of 589 terms
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tropopause break line—On a tropopause chart, a line drawn to show the edge of a tropopause “leaf.” See tropopause, multiple tropopause.
tropopause chart—A synoptic chart showing the contour lines of the tropopause and tropopause break lines.
tropopause fold—Local folding of the tropopause over an intense cyclone.
tropopause funnel—A sharp depression in the level of the tropopause; found occasionally above strong frontal zones and intense cyclones. A linear fold of the tropopause often has a funnel-like appearance in a vertical cross section through the fold. See tropopause fold.
tropopause inversion—(Sometimes called upper inversion.) The decrease in the lapse rate of temperature encountered at the level of the tropopause.
tropopause leaf—See tropopause.
tropopause wave—A wave that occurs along the surface of the tropopause, as an internal wave.
tropopause—The boundary between the troposphere and stratosphere, usually characterized by an abrupt change of lapse rate. The change is in the direction of increased atmospheric stability from regions below to regions above the tropopause. Its height varies from 15 to 20 km (9 to 12 miles) in the Tropics to about 10 km (6 miles) in polar regions. In polar regions in winter it is often difficult or impossible to determine just where the tropopause lies, since under some conditions there is no abrupt change in lapse rate at any height. It has become apparent that the tropopause consists of several discrete, overlapping “leaves,” a multiple tropopause, rather than a single continuous surface. In general, the leaves descend, step-wise, from the equator to the poles.
troposphere—That portion of the atmosphere from the earth's surface to the tropopause; that is, the lowest 10–20 km (6–12 mi) of the atmosphere; the portion of the atmosphere where most weather occurs. The troposphere is characterized by decreasing temperature with height, appreciable vertical wind motion, appreciable water vapor, and weather. Dynamically, the troposphere can be divided into the following layers: surface boundary layer, Ekman layer, and free atmosphere. See atmospheric shell.
tropospheric ozone—A term used to distinguish ozone present in the troposphere from the more commonly talked about stratospheric ozone layer. Tropospheric ozone results from transport from the stratosphere and from photochemical production (oxidation of carbon monoxide, methane, and other hydrocarbons). In remote regions of the troposphere, production and loss of ozone are nearly in balance, while in regions impacted by anthropogenic NOx and hydrocarbon emissions, net ozone production occurs.
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