Information about Tropopause
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The tropopause is between the troposphere and the stratosphere. The layers are not to scale.
The tropopause is a boundary region in the atmosphere between the troposphere and the stratosphere. Here the air ceases to cool at -50°C, and the air becomes almost completely dry.
The troposphere is the lowest of the Earth's atmospheric layers and is the layer in which all of what we call "weather" occurs. It begins at ground level and ranges in height from an average of 6 km (4 miles) at the poles to 17 km (11 miles) at the equator. At the equator, the stratosphere begins at roughly 17 km (11 miles) in altitude, and it may reach as high as 50 km (31 miles) from the earth's surface. It is at its highest level over the equator and the lowest over the geographical north pole and south pole. On account of this, the coolest layer in the atmosphere lies at about 17 km over the equator. There are two types of tropopauses, viz. equatorial tropopause, and polar tropopause.
Measuring the lapse rate through the troposphere and the stratosphere identifies the location of the tropopause. In the troposphere, the lapse rate is, on average, 6.5 °C per kilometre. That is to say, for every kilometre in height, the temperature decreases by 6.5 degrees Celsius. In the stratosphere, however, the temperature increases with altitude. The region of the atmosphere where the lapse rate changes from positive (in the troposphere) to negative (in the stratosphere), ie, where the temperature no longer decreases with altitude but rather increases, is defined as the tropopause. This occurs at the equilibrium level (EL), a value important in atmospheric thermodynamics. The exact definition used by the World Meteorological Organization is:
- the lowest level at which the lapse rate decreases to 2 °C/km or less, provided that the average lapse rate between this level and all higher levels within 2 km does not exceed 2 °C/km.
Alternatively, a dynamic definition of the tropopause is used with potential vorticity instead of vertical temperature gradient as the defining variable. There is no universally used threshold: the most common ones are: the tropopause lies at the 2 PVU or 1.5 PVU surface. PVU stands for potential vorticity unit. This threshold will be taken as a positive or negative value (e.g. 2 and -2 PVU), giving surfaces located in the northern and southern hemisphere respectively. To define a global tropopause in this way, the two surfaces arising from the positive and negative thresholds need to be joined near the equator using another type of surface such as a constant potential temperature surface.
It is also possible to define the tropopause in terms of chemical composition. For example, the lower stratosphere has much higher ozone concentrations than the upper troposphere, but much lower water vapor concentrations, so appropriate cutoffs can be used.
The tropopause is not a "hard" boundary. Vigorous thunderstorms, for example, particularly those of tropical origin, will overshoot into the lower stratosphere and undergo a brief (hour-order) low-frequency vertical oscillation. Such oscillation sets up a low-frequency atmospheric wave train capable of affecting both atmospheric and oceanic currents in the region.
See also
Earth's atmosphere |
|---|
| Troposphere • Stratosphere • Mesosphere • Thermosphere • Exosphere |
| Tropopause • Stratopause • Mesopause • Thermopause / Exobase |
| Ozone layer • Turbopause • Ionosphere |
Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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not to scale.]]
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and aerosols.
The average depth of the troposphere is about 11 km in the middle latitudes.
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The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and aerosols.
The average depth of the troposphere is about 11 km in the middle latitudes.
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to scale: from Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius. (click to enlarge)]]
The stratosphere is the second layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
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The stratosphere is the second layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
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weather is the set of all extant phenomena in a given atmosphere at a given time. The term usually refers to the activity of these phenomena over short periods (hours or days), as opposed to the term climate, which refers to the average atmospheric conditions over longer periods of
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equator is an imaginary line on the Earth's surface equidistant from the North Pole and South Pole. It thus divides the Earth into a Northern Hemisphere and a Southern Hemisphere. The equators of other planets and astronomical bodies are defined analogously.
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North is one of the four cardinal directions, specifically the direction that, in Western culture, is treated as the primary direction: north is used (explicitly or implicitly) to define all other directions; the (visual) top edges of maps usually correspond to the
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South is most commonly a noun, adjective, or adverb indicating direction or geography.
South is one of the four cardinal directions or compass points. It is the opposite of North and at right angles to East and West.
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South is one of the four cardinal directions or compass points. It is the opposite of North and at right angles to East and West.
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The lapse rate is defined as the negative of the rate of change in an atmospheric variable, usually temperature, with height observed while moving upwards through an atmosphere.
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trillion fold).]]
Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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In meteorology, the equilibrium level (EL), or level of neutral buoyancy (LNB), is the height at which a rising parcel of air is at a temperature of equal warmth to it.
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In the physical sciences, atmospheric thermodynamics is the study of heat and energy transformations in the earth’s atmospheric system. Following the fundamental laws of classical thermodynamics, atmospheric thermodynamics studies such phenomenon as properties of moist air,
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The World Meteorological Organization (WMO) is an intergovernmental organization with a membership of 188 Member States and Territories. It originated from the International Meteorological Organization (IMO), which was founded in 1873.
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Potential vorticity (PV) is a quantity which is proportional to the product of vorticity and stratification that, following a parcel of air or water, can only be changed by diabatic or frictional processes.
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In meteorology, the potential vorticity unit (PVU) is defined as 10-6 K m2 kg-1 s-1.
In adiabatic, frictionless flow, potential vorticity
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In adiabatic, frictionless flow, potential vorticity
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The potential temperature of a parcel of fluid at pressure is the temperature that the parcel would acquire if adiabatically brought to a standard reference pressure , usually 1000 millibars.
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sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article. Please include more appropriate citations from reliable sources.
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Water vapor or water vapour (see spelling differences), also aqueous vapor, is the gas phase of water. Water vapor is one state of the water cycle within the hydrosphere.
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thunderstorm, also called an electrical storm or lightning storm, is a form of weather characterized by the presence of lightning and its attendant thunder produced from a cumulonimbus cloud.
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Convective overshoot is the phenomenon of convection carrying material beyond an unstable region of the atmosphere into a stratified, stable region. Overshoot is caused by the momentum of the convecting material, which carries the material beyond the unstable region.
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- ''For other uses, see oscillator (disambiguation)
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The maximum parcel level (MPL) is the highest level in the atmosphere that a moist convectively rising air parcel will reach after ascending through the free convective layer (FCL) and reaching the equilibrium level (EL) where it loses buoyancy.
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Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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not to scale.]]
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and aerosols.
The average depth of the troposphere is about 11 km in the middle latitudes.
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The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and aerosols.
The average depth of the troposphere is about 11 km in the middle latitudes.
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to scale: from Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius. (click to enlarge)]]
The stratosphere is the second layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
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The stratosphere is the second layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
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mesosphere (from the Greek words mesos = middle and sphaira = ball) is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere.
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The thermosphere is the layer of the earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization. (see also: ionosphere). It is the fourth atmospheric layer from earth.
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exosphere is the uppermost layer of the atmosphere. On Earth, its lower boundary at the edge of the thermosphere is estimated to be 500 km to 1000 km above the Earth's surface, and its upper boundary at about 10,000 km.
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The stratopause is the level of the atmosphere which is the boundary between two layers, stratosphere and the mesosphere. In the stratosphere the temperature increases with altitude, and the stratopause is the section where a maximum in the temperature occurs.
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mesosphere (from the Greek words mesos = middle and sphaira = ball) is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere.
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The Thermopause is the atmospheric boundary of Earth's energy system, located at the top of the thermosphere.
Below this, the atmosphere is defined to be active on the insolation received, due to the increased presence of heavier gases such as monoatomic oxygen.
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Below this, the atmosphere is defined to be active on the insolation received, due to the increased presence of heavier gases such as monoatomic oxygen.
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