Knippertz, P, Fink, AH and Pohle, S (2009) Comments on "Dry-Season Precipitation in Tropical West Africa and Its Relation to Forcing from the Extratropics'' Reply. Monthly Weather Review, 137 (9). 3151 - 3157. ISSN 0027-0644
Abstract
Hydrostatic tendency equations of pressure and geopotential have been used in various forms since the beginning of the twentieth century. In contrast to classical mass flux divergence formulations, all forms that involve vertical integrals of temperature tendencies contain an additional term related to geopotential tendency at the upper limit of the integral. In many previous studies, including a recent work by two of the authors on a case of unusual wintertime precipitation in tropical West Africa, it has been assumed that there exists a pressure level in the stratosphere (usually 100 or 50 hPa) where these tendencies become negligible.This assumption implies a direct relation between net column heating and surface pressure fall. Prompted by a critique of Spengler and Egger, the validity of the concept of a stratospheric level of insignificant dynamics is tested here for the previously studied case on the basis of operational analyses from the ECMWF. At least for low latitudes, significant tendencies with some spatial and temporal variations are found up to 10 hPa, which renders a general neglect of this term on a fixed pressure level problematic. These results call for a more detailed investigation of the dynamical causes of the analyzed tendencies, a reevaluation of some previous work, and a more careful design of future studies on this subject.
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Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Copyright [2009] 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: | Height Tendency |
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: | 21 Oct 2013 11:55 |
Last Modified: | 15 Sep 2014 02:53 |
Published Version: | http://dx.doi.org/10.1175/2009MWR3006.1 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/2009MWR3006.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:76618 |