336:
convection. There is a major limitation of this measure of stability however, which is that it does not take the thermodynamic properties (saturation mixing ratio and therefore the shape of adiabats in the lower troposphere) of the air into account. A more refined measure of stability has since been developed, named the estimated inversion strength, which pays closer attention to the thermodynamic properties of the air in the lower troposphere.
45:
183:
is released into the air parcel. Moist air has more water vapor than dry air, so more latent heat is released into the parcel of moist air as it rises. Dry air does not have as much water vapor, therefore dry air cools at a higher rate with vertical movement than moist air. As a result of the latent
195:
and temperature determine the stability of the air and the resulting weather. Cool, dry air is very stable and resists vertical movement, which leads to good and generally clear weather. The greatest instability occurs when the air is moist and warm, as it is in the tropical regions in the summer.
170:
When air rises, moist air in which condensation has occurred cools at a lower rate than dry air (including moist air in which condensation has not yet occurred). That is, for the same upwards vertical movement and starting temperature, a parcel of moist air will be warmer than a parcel of dry air.
335:
that caps the planetary boundary layer on earth, and also indicates the level of convective stability of an air column at a given location. Regions with negative LTS have a larger potential temperature on the surface than in the mid-troposphere, which makes the air column unstable and encourages
188:). The dry adiabatic lapse rate (for unsaturated air) is 3 °C (5.4 °F) per 1,000 vertical feet (300 m). The moist adiabatic lapse rate varies from 1.1 to 2.8 °C (2.0 to 5.0 °F) per 1,000 vertical feet (300 m).
38:
118:
cooling and heating are phenomena of rising or descending air. Rising air expands and cools due to the decrease in air pressure as altitude increases. The opposite is true of descending air; as
266:
184:
heat that is released during water vapor condensation, moist air has a relatively lower adiabatic lapse rate than dry air. This makes moist air generally less stable than dry air (see
295:
566:
326:
129:
The adiabatic lapse rate is the rate at which the temperature of a rising or falling air mass lowers or increases per distance of vertical displacement. The ambient or
91:, where an air mass is displaced upwards as it is blown by wind up the rising slope of a mountain range) tend to become larger, resulting in turbulent airflow and
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199:
The ambient lapse rate differs in different meteorological conditions, but, on average, is 2 °C (3.6 °F) per 1,000 vertical feet (300 m).
1010:
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708:
185:
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of descending air increases as it is compressed. Adiabatic heating and adiabatic cooling are terms used to describe this temperature change.
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1005:
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420:
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is the temperature change in the (non-displaced) air per vertical distance. Instability results from difference between the
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670:
984:
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675:
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Lower tropospheric stability (commonly referred to as LTS) is a meteorological parameter that is commonly used in
898:
832:
660:
196:
Typically, thunderstorms appear on a daily basis in these regions due to the instability of the surrounding air.
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167:
relative to the atmosphere. As cooler air is more dense, the rise of such an airmass would tend to be resisted.
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relative to the atmosphere. As warmer air is less dense, such an air mass would tend to continue to rise.
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494:"On the Relationship between Stratiform Low Cloud Cover and Lower-Tropospheric Stability"
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903:
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Convective
Instability, denoted in the red highlighted region ("positive area"), on a
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It was first introduced as a simple but useful measure of the strength of the
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rapidly than the air in which it is moving. Hence, such an air mass becomes
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rapidly than the air in which it is moving. Hence, such an airmass becomes
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in the air parcel due to expansion cooling. As water vapor condenses,
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makes vertical movement difficult, and small vertical disturbances
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412:
Encyclopedia of
Weather and Climate, Revised Edition, 2-Volume Set
43:
632:
211:. It is computed at a given location on Earth and is defined as
159:
than the ambient lapse rate, an air mass displaced upward cools
144:
than the ambient lapse rate, an air mass displaced upward cools
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665:
137:
of an air mass and the ambient lapse rate in the atmosphere.
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10.1175/1520-0442(1993)006<1587:TSCOLS>2.0.CO;2
492:
Wood, Robert; Bretherton, Christopher S. (December 2006).
30:
For a more general discussion of the same phenomenon, see
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Klein, Stephen A.; Hartmann, Dennis L. (August 1993).
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of an air parcel at the 700 hPa pressure level, and
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580:
72:refers to its ability to resist vertical motion. A
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27:Ability of an air mass to resist vertical motion
87:atmosphere, vertical air movements (such as in
39:public domain text created by the US government
261:{\displaystyle LTS=\theta _{700}-\theta _{0},}
95:activity. Instability can lead to significant
560:
438:"The Seasonal Cycle of Low Stratiform Clouds"
328:is the potential temperature at the surface.
8:
709:Convective available potential energy (CAPE)
415:. Sonlight Christian -m. pp. 435–436.
155:Conversely, if the adiabatic lapse rate is
567:
553:
545:
409:Allaby, Michael; Garratt, Richard (2007).
392:United States Department of Transportation
387:Pilot's Handbook of Aeronautical Knowledge
517:
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186:convective available potential energy
32:Convective available potential energy
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671:Convective condensation level (CCL)
877:Equivalent potential temperature (
25:
729:Conditional symmetric instability
575:Meteorological data and variables
358:Conditional symmetric instability
99:, extensive vertical clouds, and
676:Lifting condensation level (LCL)
661:Cloud condensation nuclei (CCN)
396:Federal Aviation Administration
140:If the adiabatic lapse rate is
924:Wet-bulb potential temperature
766:Level of free convection (LFC)
1:
1011:Severe weather and convection
967:Pressure-gradient force (PGF)
889:Sea surface temperature (SST)
724:Convective momentum transport
398:. 2016. pp. 12–12–12–13.
290:{\displaystyle \theta _{700}}
781:Bulk Richardson number (BRN)
203:Lower tropospheric stability
985:Maximum potential intensity
751:Free convective layer (FCL)
714:Convective inhibition (CIN)
321:{\displaystyle \theta _{0}}
1027:
1006:Atmospheric thermodynamics
919:Wet-bulb globe temperature
776:Maximum parcel level (MPL)
37:This article incorporates
36:
29:
899:Thermodynamic temperature
833:Forest fire weather index
83:out and disappear. In an
18:Instability (meteorology)
821:Equivalent temperature (
734:Convective temperature (
618:Surface weather analysis
131:environmental lapse rate
868:Potential temperature (
613:Surface solar radiation
171:This is because of the
858:Relative humidity (RH)
746:Equilibrium level (EL)
719:Convective instability
322:
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62:convective instability
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346:Free convective layer
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299:potential temperature
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47:
947:Atmospheric pressure
914:Wet-bulb temperature
816:Dry-bulb temperature
811:Dew point depression
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135:adiabatic lapse rate
120:atmospheric pressure
50:Skew-T log-P diagram
909:Virtual temperature
894:Temperature anomaly
588:Adiabatic processes
510:2006JCli...19.6425W
454:1993JCli....6.1587K
209:atmospheric physics
191:The combination of
681:Precipitable water
519:10.1175/JCLI3988.1
498:Journal of Climate
442:Journal of Climate
318:
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89:orographic lifting
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962:Pressure gradient
771:Lifted index (LI)
504:(24): 6425–6432.
16:(Redirected from
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448:(8): 1587–1606.
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379:"Weather Theory"
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686:Precipitation
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648:Condensation
533:22 September
531:. Retrieved
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477:22 September
475:. Retrieved
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352:Lifted index
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173:condensation
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952:Baroclinity
799:Dew point (
791:Temperature
691:Water vapor
181:latent heat
177:water vapor
124:temperature
58:meteorology
1000:Categories
929:Wind chill
843:Heat index
701:Convection
638:Wind shear
623:Visibility
603:Lapse rate
365:References
97:turbulence
93:convective
77:atmosphere
628:Vorticity
608:Lightning
593:Advection
333:inversion
310:θ
279:θ
247:θ
243:−
234:θ
116:Adiabatic
111:Mechanism
66:stability
977:Velocity
939:Pressure
853:Humidity
756:Helicity
598:Buoyancy
528:18011630
472:26198436
340:See also
193:moisture
103:such as
85:unstable
70:air mass
848:Humidex
761:K Index
581:General
506:Bibcode
450:Bibcode
297:is the
526:
470:
419:
270:where
165:cooler
157:higher
150:warmer
81:dampen
74:stable
68:of an
656:Cloud
524:S2CID
468:JSTOR
382:(PDF)
360:(CSI)
348:(FCL)
142:lower
633:Wind
535:2022
479:2022
417:ISBN
354:(LI)
161:more
146:less
666:Fog
514:doi
458:doi
283:700
238:700
175:of
64:or
56:In
1002::
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739:c
736:T
568:e
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446:6
425:.
314:0
256:,
251:0
230:=
227:S
224:T
221:L
52:.
41:.
34:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
