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Depiction of where the planetary boundary layer lies on a sunny day. In meteorology, the planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL) or peplosphere, is the lowest part of the atmosphere and its behaviour is directly influenced by its contact with a planetary surface. [1]
Representations of the atmospheric boundary layer in global climate models play a role in simulations of past, present, and future climates.Representing the atmospheric boundary layer (ABL) within global climate models (GCMs) are difficult due to differences in surface type, scale mismatch between physical processes affecting the ABL and scales at which GCMs are run, and difficulties in ...
The logarithmic profile of wind speeds is generally limited to the lowest 100 m of the atmosphere (i.e., the surface layer of the atmospheric boundary layer). The rest of the atmosphere is composed of the remaining part of the PBL (up to around 1 km) and the troposphere or free atmosphere.
The third layer is the mesosphere which extends from 50 km (31 mi) to about 80 km (50 mi). There are other layers above 80 km, but they are insignificant with respect to atmospheric dispersion modeling. The lowest part of the troposphere is called the planetary boundary layer (PBL), or sometimes the atmospheric boundary layer.
The atmospheric boundary layer (ABL) potential temperature perturbation is defined as the difference between the potential temperature of the ABL and the potential temperature of the free atmosphere above the ABL.
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.
The atmospheric surface layer is the lowest part of the atmospheric boundary layer (typically the bottom 10% where the log wind profile is valid). The ocean has two surface layers: the benthic, found immediately above the sea floor, and the marine surface layer, at the air-sea interface.
The wind profile power law relationship is = where is the wind speed (in metres per second) at height (in metres), and is the known wind speed at a reference height .The exponent is an empirically derived coefficient that varies dependent upon the stability of the atmosphere.