Elevated inversion layer that caps the part of the atmosphere closest to the ground
This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations.(March 2013) (Learn how and when to remove this message)
A capping inversion limits the vertical development of clouds. In this image taken near Kreuzberg (Rhön), the inversion is below the top of the mountain tops.Diagram showing the daily changes to the capping inversion on top of Earth's planetary boundary layer.
A capping inversion is an elevated inversion layer that caps a convective planetary boundary layer.
The boundary layer is the part of the atmosphere which is closest to the ground. Normally, the sun heats the ground, which in turn heats the air just above it. Thermals form when this warm air rises into the cold air (warm air is less dense than cold air), a process called convection. A convective layer such as this has the potential for cloud formation, since condensation occurs as the warm air rises and cools.
An inversion occurs when the normal temperature (warm air below, cold air above) profile is reversed, creating a stable configuration of dense, cold air sitting below lighter, warm air. An elevated inversion layer is thus a region of warm air above a region of cold air, but higher in the atmosphere (generally not touching the surface).
A capping inversion occurs when there is a boundary layer with a normal temperature profile (warm air rising into cooler air) and the layer above that is an inversion layer (cooler air below warm air). Cloud formation from the lower layer is "capped" by the inversion layer. Air stagnation may result from a capping inversion from diffusing from a region, increasing the concentration of pollutants and exacerbating poor air quality.[1] If the capping inversion layer or "cap" is too strong it will prevent thunderstorms from developing. A strong cap can result in foggy conditions.
However, if the air at the surface is unstable enough, strong updrafts can be forced through the capping inversion. This selective process of only allowing the strongest updrafts to form thunderstorms often results in outbreaks of severe weather. The role of capping inversions in bolstering the intensity of severe weather was realized in conceptual models that were developed by atmospheric science researchers in the late 1960s and had been recognized as a characteristic of tornado-producing airmasses as early as 1954.[2][3] In some severe weather events, this capping inversion can emerge when a warm and dry mixed layer originating over a high plateau moves over a cooler and moister airmass, forming an "elevated mixed layer" (EML).[4] EMLs can be found worldwide downwind of high terrain, such as over South Asia, eastern Australia, east of the Rocky Mountains in the central U.S. and northern Mexico, and east of the foothills of the Andes.[4][5]
^Bailey, Adriana; Chase, Thomas N.; Cassano, John J.; Noone, David (June 2011). "Changing Temperature Inversion Characteristics in the U.S. Southwest and Relationships to Large-Scale Atmospheric Circulation". Journal of Applied Meteorology and Climatology. 50 (6): 1307–1323. doi:10.1175/2011JAMC2584.1.
^Carlson, Toby N.; Farrell, Robert J. (1983). "The Lid Strength as an Aid in Predicting Severe Local Storms" (PDF). National Weather Digest. 8 (2). National Weather Association: 27–39. Retrieved 22 May 2022.
^Banacos, Peter C.; Ekster, Michael L. (1 August 2010). "The Association of the Elevated Mixed Layer with Significant Severe Weather Events in the Northeastern United States*". Weather and Forecasting. 25 (4). American Meteorological Society: 1082–1102. Bibcode:2010WtFor..25.1082B. doi:10.1175/2010WAF2222363.1.
^ abCarlson, T. N.; Benjamin, S. G.; Forbes, G. S.; Li, Y-F. (July 1983). "Elevated Mixed Layers in the Regional Severe Storm Environment: Conceptual Model and Case Studies". Monthly Weather Review. 111 (7): 1453–1474. doi:10.1175/1520-0493(1983)111<1453:EMLITR>2.0.CO;2.
^Ribeiro, Bruno Z.; Bosart, Lance F. (January 2018). "Elevated Mixed Layers and Associated Severe Thunderstorm Environments in South and North America". Monthly Weather Review. 146 (1): 3–28. doi:10.1175/MWR-D-17-0121.1.
A cappinginversion is an elevated inversion layer that caps a convective planetary boundary layer. The boundary layer is the part of the atmosphere which...
Earth's surface to a cappinginversion that typically locates at a height of 1–2 km by midafternoon over land. Below the cappinginversion (10–60% of CBL depth...
intensify as a result of the strong cappinginversion overhead. However, these storms also caused the cappinginversion to gradually diminish; the emergent...
atmospheric stability and the height of any convective boundary layer or cappinginversion. This effect is even larger over the sea, where there is much less...
advection and surface air cooling. Surface cooling causes a small cappinginversion to form aloft allowing the air to become stable. Incoming weather...
development of turkey towers could signify the breaking or weakening of a cappinginversion, and an area where these consistently form is an "agitated area",...
above the earth, it is called an inversion aloft (sometimes referred to as a cappinginversion). The air within an inversion aloft is very stable with very...
development; such rapid development usually occurs when CAPE stored by a cappinginversion is released when the "lid" is broken by heating or mechanical lift...
vertical axis. This forms a deep rotating updraft, the mesocyclone. A cap or cappinginversion is usually required to form an updraft of sufficient strength....
greatly inhibiting the potential for rainfall. A prominent descending cappinginversion forced even more stabilization of the atmosphere, which led to enhanced...
decreases with increasing altitude until it reaches a cappinginversion, which is a type of inversion layer where warmer air sits higher in the atmosphere...
describe either (or both) weak lapse rates, thus weak instability or a cappinginversion. The atmosphere on August 28 was significantly more unstable as the...
base begins near the lifted condensation level (LCL). When such a cappinginversion is present, this will remain as shallow, moist convection (small cumulus...
onshore wind flow from the Gulf of Mexico and the persistence of a cappinginversion aloft led to an accumulation of moist air over the state. Dew points...
Richardson Number (BRN) Bulk shear Buoyancy Cappinginversion (cap) Center for Analysis and Prediction of Storms (CAPS) Center for Severe Weather Research (CSWR)...
planetary boundary layer can have lower level clouds located around the cappinginversion top. The two main types of clouds within the planetary boundary layer...
Though this activity lacked much vigor at its onset due to a strong cappinginversion, the convective cells began to show organization as they progressed...
Roller coasters are widely known for their drops, inversions, airtime, and other intense ride elements that contribute to a thrilling ride experience....
the increase of temperature with height that is present during a cappinginversion. Forcing mechanisms that can lead to the eroding of inhibition are...
cold front, but that this environment would likely be contained by a cappinginversion for most of the day. By the afternoon hours, the SPC expected the...
In mathematics, the Fourier inversion theorem says that for many types of functions it is possible to recover a function from its Fourier transform. Intuitively...
moderate instability. However, dry air at higher levels created a cappinginversion, limiting the number of thunderstorms that could develop. Later on...
however, event failed to consolidate with only isolated tornadoes and scattered severe wind reported. A shortwave ridge maintained a cappinginversion....
Mississippi, at 18:00 UTC revealed the presence of a cappinginversion across the region. This cap was expected to weaken across central Mississippi, while...
Global Information
