Birch, CE, Webster, S, Peatman, SC et al. (4 more authors) (2016) Scale interactions between the MJO and the western Maritime Continent. Journal of Climate, 29 (7). pp. 2471-2492. ISSN 0894-8755
Abstract
State-of-the-art regional climate model simulations that are able to resolve key mesoscale circulations are used, for the first time, to understand the interaction between the large-scale convective environment of the MJO and processes governing the strong diurnal cycle over the islands of the Maritime Continent (MC). Convection is sustained in the late afternoon just inland of the coasts due to sea breeze convergence. Previous work has shown that the variability in MC rainfall associated with the MJO is manifested in changes to this diurnal cycle; land-based rainfall peaks before the active convective envelope of the MJO reaches the MC, whereas oceanic rainfall rates peak whilst the active envelope resides over the region. The model simulations show that the main controls on oceanic MC rainfall in the early active MJO phases are the large-scale environment and atmospheric stability, followed by high oceanic latent heat flux forced by high near-surface winds in the later active MJO phases. Over land, rainfall peaks before the main convective envelope arrives (in agreement with observations), even though the large-scale convective environment is only moderately favourable for convection. The causes of this early rainfall peak are convective triggers from land-sea breeze circulations that are strong due to high surface insolation and surface heating. During the peak MJO phases cloud cover increases and surface insolation decreases, which weakens the strength of the mesoscale circulations and reduces land-based rainfall, even though the large-scale environment remains favourable for convection at this time. Hence, scale interactions are an essential part of the MJO transition across the MC.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Copyright 2016 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 (https://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyrights@ametsoc.org. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | Geographic location/entity; Maritime Continent; Circulation/ Dynamics; Convective-scale processes; Madden-Julian oscillation; Atm/Ocean Structure/ Phenomena; Rainfall; Sea breezes; Models and modeling; Cloud resolving models |
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) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number Met Office L0627 |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Jan 2016 16:39 |
Last Modified: | 11 Apr 2017 11:21 |
Published Version: | http://dx.doi.org/10.1175/JCLI-D-15-0557.1 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/JCLI-D-15-0557.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:93625 |