Drizzle suppression in ship tracks
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Authors
Ferek, Ronald J.
Garrett, Timothy
Hobbs, Peter V.
Strader, Scott
Johnson, Doug
Taylor, Jonathan
Nielsen, Kurt
Ackerman, Andrew S.
Kogan, Yefim
Liu, Qingfu
Subjects
Advisors
Date of Issue
2000-08-15
Date
Publisher
American Meteorological Society
Language
Abstract
Although drizzle was a relatively infrequent occurrence during the Monterey Area Ship Track study, diverse measurements from several source produced data signals consistent with a reduction in drizzle drops in stratus clouds affected by ship effluents. Concurrent increases in liquid water in the cloud droplet size range, due to redistribution from the drizzle mode, were not always observed, possibly because of the relatively small and often negligible amounts of water in the drizzle mode. Significant changes in cloud droplet size distribution, as well as reductions in drizzle flux and concentrations of drops >50-um radius, were observed in ship tracks when drizzle was more uniformly present in the ambient cloud. Radiometric measurements showed that increased concentrations in ship tracks, which resulted in reduced droplet size, can significantly alter the liquid water path. Radar observations indicated that the reduced reflectivities of ship tracks compared with ambient clouds may be due to reductions in the concentrations of larger drops and/or reductions in the sizes of these drops. Two independent modeling studies showed decreases in drizzle in ship tracks due to the presence of smaller cloud droplets that reduced the efficiency of drop growth by collisions.
Type
Article
Description
Series/Report No
Department
Department of Meteorology
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
This work was sponsored by the Department of the Navy, Office of Naval Research, under Grant N00014-92-J-1587
Funder
This work was sponsored by the Department of the Navy, Office of Naval Research, under Grant N00014-92-J-1587
Format
21 p.
Citation
Journal of the Atmospheric Sciences, v. 57, August 15, 2000, Pp. 2707-2728
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.