NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Climate Impacts of Ice NucleationSeveral different ice nucleation parameterizations in two different General Circulation Models (GCMs) are used to understand the effects of ice nucleation on the mean climate state, and the Aerosol Indirect Effects (AIE) of cirrus clouds on climate. Simulations have a range of ice microphysical states that are consistent with the spread of observations, but many simulations have higher present-day ice crystal number concentrations than in-situ observations. These different states result from different parameterizations of ice cloud nucleation processes, and feature different balances of homogeneous and heterogeneous nucleation. Black carbon aerosols have a small (0.06 Wm(exp-2) and not statistically significant AIE when included as ice nuclei, for nucleation efficiencies within the range of laboratory measurements. Indirect effects of anthropogenic aerosols on cirrus clouds occur as a consequence of increasing anthropogenic sulfur emissions with different mechanisms important in different models. In one model this is due to increases in homogeneous nucleation fraction, and in the other due to increases in heterogeneous nucleation with coated dust. The magnitude of the effect is the same however. The resulting ice AIE does not seem strongly dependent on the balance between homogeneous and heterogeneous ice nucleation. Regional effects can reach several Wm2. Indirect effects are slightly larger for those states with less homogeneous nucleation and lower ice number concentration in the base state. The total ice AIE is estimated at 0.27 +/- 0.10 Wm(exp-2) (1 sigma uncertainty). This represents a 20% offset of the simulated total shortwave AIE for ice and liquid clouds of 1.6 Wm(sup-2).
Document ID
20140001045
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1029/2012JD017950
Authors
Gettelman, Andrew (National Center for Atmospheric Research Boulder, CO, United States)
Liu, Xiaohong (Pacific Northwest National Lab. Richland, WA, United States)
Barahona, Donifan (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Lohmann, Ulrike (Eidgenoessische Technische Hochschule Zurich, Switzerland)
Chen, Celia (National Center for Atmospheric Research Boulder, CO, United States)
Date Acquired
March 5, 2014
Publication Date
October 1, 2012
Publication Information
Publication: Journal of Geophysical Research
Volume: 112
Issue: D20 27
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC-E-DAA-TN8104
Funding Number(s)
WBS: WBS 802678.02.17.01.07
CONTRACT_GRANT: NNX09AJ05G
CONTRACT_GRANT: NNG11HP16A
CONTRACT_GRANT: DTRT57-10-C-10012
CONTRACT_GRANT: DE-AC06-76RLO 1830
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available