Birch, CE, Parker, DJ, O'Leary, A et al. (4 more authors) (2013) Impact of soil moisture and convectively generated waves on the initiation of a West African mesoscale convective system. Quarterly Journal of the Royal Meteorological Society, 139 (676). pp. 1712-1730. ISSN 0035-9009
Abstract
A mesoscale convective system (MCS) case study was observed over northeast Mali as part of the African Monsoon Multidisciplinary Analysis (AMMA) on 31 July 2006. Observations of this case suggest that the soil-moisture heterogeneity and atmospheric gravity waves emitted from a ‘parent’ MCS were important trigger mechanisms for this system. This study uses high-resolution Met Office Unified Model (MetUM) simulations to assess the importance of the synoptic circulation, land-surface and gravity waves in the initiation and development of the MCS. During the early afternoon shallow convection developed over a region of dry soil within a synoptic-scale convergence zone, which was caused by the confluence of the southerly monsoon flow with winds associated with the circulation around the Saharan heat low. Two pronounced waves were emitted from a nearby ‘parent’ storm and propagated towards the convergence zone. When the second wave reached the location of the shallow convection, deep convection was immediately initiated. Further convective cells developed later in the afternoon over dry soil, many adjacent to strong soil moisture gradients; these aggregated with the main storm, which later developed into the case study MCS. A comparison of model simulations with/without the soil-moisture heterogeneity and gravity waves shows that the synoptic-scale circulation and convergence zones, specified by the atmospheric analysis, were the most important factors for the successful simulation of the MCS. If the location of the initiation of the system is to be forecast accurately, the land-surface, that is, the soil moisture, must be represented adequately. In order to reproduce the timing of the secondary initiation of convection correctly the model must be able to capture gravity waves that are emitted by existing systems.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | (c) 2012, Royal Meteorological Society. This is the peer reviewed version of the following article: 'Birch, CE, Parker, DJ, O'Leary, A, Marsham, JH, Taylor, CM, Harris, PP and Lister, GMS (2013) Impact of soil moisture and convectively generated waves on the initiation of a West African mesoscale convective system. Quarterly Journal of the Royal Meteorological Society, 139 (676). pp. 1712-1730', which has been published in final form at http://doi.org/10.1002/qj.2062. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
Keywords: | mesoscale convective system (MCS); secondary initiation; gravity wave; soil moisture; AMMA |
Dates: |
|
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) |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 Jul 2016 15:17 |
Last Modified: | 23 Jan 2018 22:15 |
Published Version: | http://doi.org/10.1002/qj.2062 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/qj.2062 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:85896 |