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contributor authorGhonima, Mohamed S.
contributor authorHeus, Thijs
contributor authorNorris, Joel R.
contributor authorKleissl, Jan
date accessioned2017-06-09T16:59:03Z
date available2017-06-09T16:59:03Z
date copyright2016/08/01
date issued2016
identifier issn0022-4928
identifier otherams-77434.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4219992
description abstracthe breakup of stratocumulus clouds over coastal land areas is studied using a combination of large-eddy simulations (LESs) and mixed-layer models (MLMs) with a focus on mechanisms regulating the timing of the breakup. In contrast with stratocumulus over ocean, strong sensible heat flux over land prevents the cloud layer from decoupling during day. As the cloud thins during day, turbulence generated by surface flux becomes larger than turbulence generated by longwave cooling across the cloud layer. To capture this shift in turbulence generation in the MLM, an existing entrainment parameterization is extended. The MLM is able to mimic cloud evolution for a variety of Bowen ratios, but only after this modification of the entrainment parameterization. Cloud lifetime depends on a combination of the cloud-top entrainment flux, the Bowen ratio of the surface, and the strength of advection of cool ocean air by the sea breeze. For dry land surface conditions, the authors? MLM suggests a breakup time a few hours after sunrise. For relatively wet land surface conditions, the cloud layer briefly breaks into partly cloudy conditions during midday, and the stratocumulus cloud reforms in the evening.
publisherAmerican Meteorological Society
titleFactors Controlling Stratocumulus Cloud Lifetime over Coastal Land
typeJournal Paper
journal volume73
journal issue8
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-15-0228.1
journal fristpage2961
journal lastpage2983
treeJournal of the Atmospheric Sciences:;2016:;Volume( 073 ):;issue: 008
contenttypeFulltext


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