Birch, CE orcid.org/0000-0001-9384-2810, Marsham, JH orcid.org/0000-0003-3219-8472, Parker, DJ orcid.org/0000-0003-2335-8198 et al. (1 more author) (2014) The scale dependence and structure of convergence fields preceding the initiation of deep convection. Geophysical Research Letters, 41 (13). pp. 4769-4776. ISSN 0094-8276
Abstract
Links between convergence and convection are poor in global models, and poor representation of convection is the source of many model biases in the tropics. State-of-the-art convection-permitting simulations allow us to analyze realistic convection statistically. The analysis of fractal dimension is used to show that in convection-permitting simulations (grid spacings 1.5, 4, and 12 km) of the West African monsoon, 50% of deep convective initiations occur in the near vicinity of low-level boundary layer convergence lines that are orientated along the mean wind. In these simulations, more than 80% of the initiations occur within large-scale (300 × 300 km) convergence, with some 20% in large-scale divergence, and almost all cases occur within local scale (60 × 60 km) convergence. The behavior alters in a simulation with a convection scheme and a grid spacing of 12 km; initiation is less frequent over convergence lines, and there is less dependency on high-magnitude low-level local convergence. Key Points Fifty percent of storms initiate along convergence lines Most initiations occur in large and local scale convergence Parameterized convection exhibits a weaker dependence on strong convergence ©2014. American Geophysical Union. All Rights Reserved.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | An edited version of this paper was published by AGU. Copyright (2014) American Geophysical Union. Birch, CE, Marsham, JH, Parker, DJ and Taylor, CM (2014) The scale dependence and structure of convergence fields preceding the initiation of deep convection. Geophysical Research Letters, 41 (13), 10.1002/2014GL060493. To view the published open abstract, go to http://dx.doi.org/10.1002/2014GL060493 |
Keywords: | convection; convection permitting; low-level convergence; Met Office Unified Model; parameterization; triggering |
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) |
Depositing User: | Symplectic Publications |
Date Deposited: | 18 Sep 2014 10:58 |
Last Modified: | 29 Oct 2020 13:16 |
Published Version: | http://dx.doi.org/10.1002/2014GL060493 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1002/2014GL060493 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80180 |