A conceptual model of a shallow circulation induced by prescribed low-level radiative cooling
Visualitza/Obre
Cita com:
hdl:2117/188008
Tipus de documentArticle
Data publicació2017-10-01
Condicions d'accésAccés obert
Llevat que s'hi indiqui el contrari, els
continguts d'aquesta obra estan subjectes a la llicència de Creative Commons
:
Reconeixement-NoComercial-SenseObraDerivada 3.0 Espanya
Abstract
A conceptual bulk model for a dry, convective boundary layer with prescribed horizontally homogeneous
and heterogeneous low-level radiative cooling rates is developed. For horizontally homogeneous radiative
cooling, the response of the system to varying its prescribed parameters is explored and formulated in terms of
nondimensional parameters. Large-eddy simulations with prescribed radiative cooling rates match the results
of the bulk model well. It is found that, depending on the strength of the surface coupling, the height of the
boundary layer (BL) either increases or decreases in response to increasing radiative BL cooling. Another
property of the system is that, for increasing surface temperature, the BL temperature decreases if the prescribed radiative BL cooling rates are strong. This counterintuitive behavior is caused by the formulation of
the entrainment rate at the inversion. Heterogeneous radiative BL cooling is found to cause a circulation
induced by pressure deviations between the area of weak radiative BL cooling and the area of strong radiative
BL cooling. Including the feedback of the induced circulation on the BL in a two-column model leads to a
modified equilibrium state, in which a weakened horizontal BL flow of about 1 m s21 is maintained for differences in radiative BL cooling rates larger than 1 K day2. Such a circulation strength is comparable to a shallow circulation caused by surface temperature differences of a few kelvins. Spatial differences in radiative BL cooling should therefore be considered as a first-order effect for the formation of shallow circulations.
CitacióNaumann, A. [et al.]. A conceptual model of a shallow circulation induced by prescribed low-level radiative cooling. "Journal of the atmospheric sciences", 1 Octubre 2017, vol. 74, p. 3129-3143.
ISSN0022-4928
Versió de l'editorhttps://journals.ametsoc.org/doi/full/10.1175/JAS-D-17-0030.1
Col·leccions
Fitxers | Descripció | Mida | Format | Visualitza |
---|---|---|---|---|
NaumannEtal2017.pdf | 1,478Mb | Visualitza/Obre |