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contributor authorHeymsfield, Andrew J.
contributor authorMiloshevich, Larry M.
contributor authorSlingo, Anthony
contributor authorSassen, Kenneth
contributor authorStarr, David O'C.
date accessioned2017-06-09T14:30:18Z
date available2017-06-09T14:30:18Z
date copyright1991/04/01
date issued1991
identifier issn0022-4928
identifier otherams-20510.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4156747
description abstractTwo altocumulus clouds, which formed at a temperature of ?30°C, were sampled using the NCAR King Air aircraft and coincident lidar during the 1986 FIRE cirrus experiment in Wisconsin. The clouds were structurally and thermodynamically similar to stratocumulus, with extensive cloudtop entrainment, a capping temperature inversion, and a dry layer above. The microphysical and radiative properties of both clouds were characterized and modeled numerically. Calculations of droplet concentration and mean diameter profiles compare favorably with the measurements when entrainment effects are incorporated in the model. Radiative transfer calculations suggest radiation played an important role in driving convection in the more dynamically unstable of the two clouds. A simple model shows that radiative cooling causes sufficient negative buoyancy in cloudtop parcels to produce convective instability and to reproduce the observed downdraft velocities. Entrainment of warmer, drier air near cloudtop is shown to partially counteract the radiatively induced negative buoyancy in the downdrafts.
publisherAmerican Meteorological Society
titleAn Observational and Theoretical Study of Highly Supercooled Altocumulus
typeJournal Paper
journal volume48
journal issue7
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/1520-0469(1991)048<0923:AOATSO>2.0.CO;2
journal fristpage923
journal lastpage945
treeJournal of the Atmospheric Sciences:;1991:;Volume( 048 ):;issue: 007
contenttypeFulltext


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