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contributor authorHeymsfield, Andrew J.
contributor authorKrämer, Martina
contributor authorLuebke, Anna
contributor authorBrown, Phil
contributor authorCziczo, Daniel J.
contributor authorFranklin, Charmaine
contributor authorLawson, Paul
contributor authorLohmann, Ulrike
contributor authorMcFarquhar, Greg
contributor authorUlanowski, Zbigniew
contributor authorVan Tricht, Kristof
date accessioned2017-06-09T16:41:54Z
date available2017-06-09T16:41:54Z
date copyright2017/01/01
date issued2016
identifier issn0065-9401
identifier otherams-72459.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4214464
description abstracthe goal of this chapter is to synthesize information about what is now known about one of the three main types of clouds, cirrus, and to identify areas where more knowledge is needed. Cirrus clouds, composed of ice particles, form in the upper troposphere, where temperatures are generally below ?30°C. Satellite observations show that the maximum-occurrence frequency of cirrus is near the tropics, with a large latitudinal movement seasonally. In situ measurements obtained over a wide range of cirrus types, formation mechanisms, temperatures, and geographical locations indicate that the ice water content and particle size generally decrease with decreasing temperature, whereas the ice particle concentration is nearly constant or increases slightly with decreasing temperature. High ice concentrations, sometimes observed in strong updrafts, result from homogeneous nucleation. The satellite-based and in situ measurements indicate that cirrus ice crystals typically differ from the simple, idealized geometry for smooth hexagonal shapes, indicating complexity and/or surface roughness. Their shapes significantly impact cirrus radiative properties and feedbacks to climate. Cirrus clouds, one of the most uncertain components of general circulation models (GCM), pose one of the greatest challenges in predicting the rate and geographical pattern of climate change. Improved measurements of the properties and size distributions and surface structure of small ice crystals (about 20 ?m) and identifying the dominant ice nucleation process (heterogeneous versus homogeneous ice nucleation) under different cloud dynamical forcings will lead to a better representation of their properties in GCM and in modeling their current and future effects on climate.
publisherAmerican Meteorological Society
titleCirrus Clouds
typeJournal Paper
journal volume58
journal titleMeteorological Monographs
identifier doi10.1175/AMSMONOGRAPHS-D-16-0010.1
journal fristpage2.1
journal lastpage2.26
treeMeteorological Monographs:;2016:;Volume( 58 )
contenttypeFulltext


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