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Author T. Dinh, A. Podglajen, A. Hertzog, B. Legras, R. Plougonven
Title Effect of gravity wave temperature fluctuations on homogeneous ice nucleation in the tropical tropopause layer Type Journal
Year 2016 Publication Atmospheric Chemistry and Physics Abbreviated Journal
Volume 16 Issue 1 Pages 35-46
Keywords
Abstract The impact of high-frequency fluctuations of temperature on homogeneous nucleation of ice crystals in the vicinity of the tropical tropopause is investigated using a bin microphysics scheme for air parcels. The imposed temperature fluctuations come from measurements during isopycnic balloon flights near the tropical tropopause. The balloons collected data at high frequency, guaranteeing that gravity wave signals are well resolved.

With the observed temperature time series, the numerical simulations with homogeneous freezing show a full range of ice number concentration (INC) as previously observed in the tropical upper troposphere. In particular, a low INC may be obtained if the gravity wave perturbations produce a non-persistent cooling rate (even with large magnitude) such that the absolute change in temperature remains small during nucleation. This result is explained analytically by a dependence of the INC on the absolute drop in temperature (and not on the cooling rate). This work suggests that homogeneous ice nucleation is not necessarily inconsistent with observations of low INCs.

Programme 914
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1680-7316 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8280
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