Journal Article

FZJ-2017-07210

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Classification of Arctic, midlatitude and tropical clouds in the mixed-phase temperature regime

Costa, A. (Corresponding author)FZJ* ; Meyer, J. ; Afchine, A.FZJ* ; Luebke, A. ; Günther, G.FZJ* ; Dorsey, J. R. ; Gallagher, M. W. ; Ehrlich, A. ; Wendisch, M. ; Baumgardner, D. ; Wex, H. ; Krämer, M.FZJ*

2017
EGU Katlenburg-Lindau

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Please use a persistent id in citations: http://hdl.handle.net/2128/15697  doi:10.5194/acp-17-12219-2017

Abstract: The degree of glaciation of mixed-phase clouds constitutes one of the largest uncertainties in climate prediction. In order to better understand cloud glaciation, cloud spectrometer observations are presented in this paper, which were made in the mixed-phase temperature regime between 0 and −38 °C (273 to 235 K), where cloud particles can either be frozen or liquid. The extensive data set covers four airborne field campaigns providing a total of 139 000 1 Hz data points (38.6 h within clouds) over Arctic, midlatitude and tropical regions. We develop algorithms, combining the information on number concentration, size and asphericity of the observed cloud particles to classify four cloud types: liquid clouds, clouds in which liquid droplets and ice crystals coexist, fully glaciated clouds after the Wegener–Bergeron–Findeisen process and clouds where secondary ice formation occurred. We quantify the occurrence of these cloud groups depending on the geographical region and temperature and find that liquid clouds dominate our measurements during the Arctic spring, while clouds dominated by the Wegener–Bergeron–Findeisen process are most common in midlatitude spring. The coexistence of liquid water and ice crystals is found over the whole mixed-phase temperature range in tropical convective towers in the dry season. Secondary ice is found at midlatitudes at −5 to −10 °C (268 to 263 K) and at higher altitudes, i.e. lower temperatures in the tropics. The distribution of the cloud types with decreasing temperature is shown to be consistent with the theory of evolution of mixed-phase clouds. With this study, we aim to contribute to a large statistical database on cloud types in the mixed-phase temperature regime.

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. 244 - Composition and dynamics of the upper troposphere and middle atmosphere (POF3-244) (POF3-244)
2. HITEC - Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) (HITEC-20170406) (HITEC-20170406)

Appears in the scientific report 2017

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Database coverage:
; ; ; ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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