[Ref Understanding Weather & Climate, Books a la Carte Edition (6th Edition) #ISBN-13: 978-0321773227 #ISBN-10: 0321773225 CH 6 Cloud Development and Forms, PPL Instruction Kit Vol2 (306) – 9th Edition, V9.2 P.568-570]
Inversions
Inversions – temperature of the ambient air increases with altitude
There are 4 types of inversions:
- Radiation inversion (i.e Surface-based temperature inversions)
- results from diabatic cooling
- associate with radiation fog on the ground level
(usually occur on clear, cool nights, with relatively little to no wind present)
- Frontal inversions
- Subsidence inversions (≠ Turbulence Inversion)
- associate with high pressure system
- the parcel of air sinking (subsiding), it encounters with compression and the temperature increases
- Turbulence inversion
- usually dry air with turbulence AND close to the ground
- the parcel of air forced downward, it will has higher temperature – refer to DALR
Features and related WX of temperature Inversion (Layer)
- Density
- Hot air, Air density lower – decreasing air density during climbing – lift and power may reduce.
- Visibility
- Below the inversion layer, lack of (not enough) convection – pollution is trapped
- If the relative humidity of the air is high, it can contribute to the formation of clouds, fog, haze, or smoke
- Turbulence and Change in Wind direction
- below the inversion layer is smooth, stable air, but wind shear is expected at the upper boundary of the layer.
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Source: https://www.aopa.org/news-and-media/all-news/2010/november/01/wx-watch-freezing-rain-facts Ice pellets – temperature inversion at higher altitude
- Ice pellets are an indication of a temperature inversion and that freezing rain exists at a higher altitude
(Ice pellets are formed because rain falls through a temperature inversion, the rain may freeze as it passes through the underlying cold air and fall to the ground in the form of ice pellets)
- Ice pellets are an indication of a temperature inversion and that freezing rain exists at a higher altitude