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Record Details

Record 4 of 356
Ice Nucleation in Deep Convection
Author and Affiliation:
Jensen, Eric(NASA Ames Research Center, Moffett Field, CA United States)
Ackerman, Andrew(NASA Ames Research Center, Moffett Field, CA United States)
Stevens, David(Lawrence Livermore National Lab., Livermore, CA United States)
Gore, Warren J. [Technical Monitor]
Abstract: The processes controlling production of ice crystals in deep, rapidly ascending convective columns are poorly understood due to the difficulties involved with either modeling or in situ sampling of these violent clouds. A large number of ice crystals are no doubt generated when droplets freeze at about -40 C. However, at higher levels, these crystals are likely depleted due to precipitation and detrainment. As the ice surface area decreases, the relative humidity can increase well above ice saturation, resulting in bursts of ice nucleation. We will present simulations of these processes using a large-eddy simulation model with detailed microphysics. Size bins are included for aerosols, liquid droplets, ice crystals, and mixed-phase (ice/liquid) hydrometers. Microphysical processes simulated include droplet activation, freezing, melting, homogeneous freezing of sulfate aerosols, and heterogeneous ice nucleation. We are focusing on the importance of ice nucleation events in the upper part of the cloud at temperatures below -40 C. We will show that the ultimate evolution of the cloud in this region (and the anvil produced by the convection) is sensitive to these ice nucleation events, and hence to the composition of upper tropospheric aerosols that get entrained into the convective column.
Publication Date: Jan 01, 2001
Document ID:
20010048416
(Acquired Jun 08, 2001)
Subject Category: METEOROLOGY AND CLIMATOLOGY
Document Type: Preprint
Meeting Information: European Geophysical Society Meeting; 25-30 Mar. 2001; Nice; France
Meeting Sponsor: European Geophysical Society; Unknown
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA United States
Organization Source: NASA Ames Research Center; Moffett Field, CA United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: CONVECTION; CRYSTALS; DROPS (LIQUIDS); FREEZING; ICE; MELTING; SIMULATION; AEROSOLS; DEPLETION; HETEROGENEITY; HUMIDITY; HYDROMETERS; LARGE EDDY SIMULATION; NUCLEATION; SAMPLING; SENSITIVITY; SULFATES; TROPOSPHERE
Availability Source: Other Sources
Availability Notes: Abstract Only
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