Simulations of an isolated two-dimensional thunderstorm : sensitivity to cloud droplet size and the presence of graupel

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dc.contributor.author Bopape, Mary-Jane Morongwa
dc.contributor.author Engelbrecht, F.A. (Francois Alwyn)
dc.contributor.author Randall, David A.
dc.contributor.author Landman, W.A. (Willem Adolf), 1964-
dc.date.accessioned 2014-05-20T13:03:53Z
dc.date.available 2014-05-20T13:03:53Z
dc.date.issued 2014-02
dc.description.abstract Cloud Resolving Models (CRMs) which are used increasingly to make operational forecasts, employ Bulk Microphysics Schemes (BMSs) to describe cloud microphysical processes. In this study two BMSs are employed in a new Nonhydrostatic σ-coordinate Model to perform two hour simulations of convection initiated by a warm bubble, using a horizontal grid resolution of 500 m. Different configurations of the two BMSs are applied, to test the effects of the presence of graupel with one scheme (2-configurations) and of changing the cloud droplet sizes in the second scheme (4-configurations), on the simulation of idealised thunderstorms. Maximum updrafts in all the simulations are similar over the first 40 minutes, but start to differ beyond this point. The first scheme simulates the development of a second convective cell that is triggered by the cold pool that develops from the outflow of the first storm. The cold pool is more intense in the simulation with graupel because of melting of graupel particles, which results in relatively large raindrops, decreases the temperature through latent heat absorption, causing stronger downdrafts, which all contribute to the formation of a more intense cold pool. The second scheme simulates the development of a second cell in two of its configurations, while two other configurations do not simulate the redevelopment. Two configurations that simulate the secondary redevelopment produce a slightly stronger cold pool just before redevelopment. Our results show that small differences in the microphysics formulations result in simulations of storm dynamics that diverge, possibly due nonlinearities in the model. en_US
dc.description.librarian hb2014 en_US
dc.description.sponsorship CSIR Natural Resources and the Environment for funding this work through parliamentary grant funding and Young Researcher Establishment Funds. The Centre for High Performance Computing (CHPC) in South Africa. The Applied Centre for Climate and Earth System Science (ACCESS) . en_US
dc.description.uri http://link.springer.com/journal/13143 en_US
dc.identifier.citation Bopape, MJM, Engelbrecht, FA, Randall, DA & Landman, WA 2014, 'Simulations of an isolated two-dimensional thunderstorm : sensitivity to cloud droplet size and the presence of graupel', Asia-Pacific Journal of Atmospheric Sciences, vol. 50, no. 2, pp. 139-151. en_US
dc.identifier.issn 1976-7633 (print)
dc.identifier.issn 1976-7951 (online)
dc.identifier.other 10.1007/s13143-014-0003-z
dc.identifier.uri http://hdl.handle.net/2263/39823
dc.language.iso en en_US
dc.publisher Springer en_US
dc.rights © The Korean Meteorological Society and Springer 2014. The original publication is available at : http://link.springer.com/journal/13143 en_US
dc.subject Atmospheric modelling en_US
dc.subject Microphysics schemes en_US
dc.subject Thunderstorm en_US
dc.subject Cold pool en_US
dc.subject Cloud Resolving Models (CRMs) en_US
dc.subject Bulk Microphysics Schemes (BMSs) en_US
dc.title Simulations of an isolated two-dimensional thunderstorm : sensitivity to cloud droplet size and the presence of graupel en_US
dc.type Postprint Article en_US


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