Fröhlich, L, Fink, AH, Knippertz, P et al. (1 more author) (2013) An objective climatology of tropical plumes. Journal of Climate, 26 (14). 5044 - 5060. ISSN 0894-8755
Abstract
The first global objective climatology of tropical plumes (TPs), obtained from a novel algorithm based on gridded 10.8-μmbrightness temperatures T, is presented for 1983-2006. TPs are defined as continuous cloud bands (>2000 km) crossing 15°Nor 15°S with T anomalies of less than220 K and a lifetime of at least 3 h. A minimum length-to-width ratio of 3 filters out elongated features. Numbers of identified TPs are sensitive to the chosen thresholds but not their geographical distribution and seasonal cycle. TPs are an important indicator of tropical-extratropical interactions with impacts on radiation and moisture. TP occurrence during boreal winter is largely confined to oceanic regions with main maxima over the South Pacific and South Atlantic as well as the eastern North Atlantic and Pacific Oceans. The geographical distribution during boreal summer is similar, but with lower frequencies, except for monsoon-influenced regions. Interannual variations over the Indo-Pacific region are strongly related to El Niño. TPs often develop downstream of extratropical upper-level troughs propagating into low latitudes, particularly over the wintertime eastern North Pacific and North Atlantic, but also in regions where mean upper-level easterlies do not generally favor equatorward Rossby wave propagation. Synoptic-scale variations in the quasi-permanent cloud bands associated with the South Pacific and South Atlantic convergence zones frequently produce TP-like anomalies, which are climatologically associated with downstream upper-level troughs. Some regions also feature TPs associated with mesoscale tropical disturbances. The new TP algorithm will serve as a basis for more in-depth studies in the future.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Copyright [2013] American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyrights@ametsoc.org. |
Keywords: | Eastern north pacific; Interannual variation; Length-to-width ratio; ROSSBY wave propagation; South atlantic convergence zones; Tropical disturbances; Tropical-extratropical interactions; Upper-level trough |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 23 Oct 2013 09:15 |
Last Modified: | 29 Mar 2018 16:33 |
Published Version: | http://dx.doi.org/10.1175/JCLI-D-12-00351.1 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/JCLI-D-12-00351.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:76581 |