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Assessment of the representation of West African storm lifecycles in convection‐permitting simulations

Crook, Julia; Klein, Cornelia; Folwell, Sonja; Taylor, Christopher M.; Parker, Douglas J.; Stratton, Rachel; Stein, Thorwald. 2019 Assessment of the representation of West African storm lifecycles in convection‐permitting simulations. Earth and Space Science, 6 (5). 818-835. https://doi.org/10.1029/2018EA000491

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Abstract/Summary

Convection‐permitting models perform better at representing the diurnal cycle and the intermittency of convective rainfall over land than parameterized‐convection models. However, most of the previous model assessments have been from an Eulerian point of view, while key impacts of the rainfall depend on a storm‐relative perspective of the system lifecycle. Here a storm‐tracking algorithm is used to generate storm‐centered Lagrangian lifecycle statistics of precipitation over West Africa from regional climate model simulations and observations. Two versions of the Met Office Unified Model with and without convection parameterization at 4, 12, and 25 km resolution were analyzed. In both of the parameterized‐convection simulations, storm lifetimes are too short compared to observations, and storms have no preferred propagation direction; the diurnal cycle of initiations and dissipations and the spatial distribution of storms are also inaccurate. The storms in the convection‐permitting simulations have more realistic diurnal cycles and lifetimes, but are not as large as the largest observed storms. The convection‐permitting model storms propagate in the correct direction, although not as fast as observed storms, and they have a much improved spatial distribution. The rainfall rate of convection‐permitting storms is likely too intense compared to observations. The improved representation of the statistics of organized convective lifecycles shows that convection‐permitting models provide better simulation of a number of aspects of high‐impact weather which are critical to climate impacts in this important geographic region, providing the high rainfall rates can be taken into account.

Item Type: Publication - Article
Digital Object Identifier (DOI): https://doi.org/10.1029/2018EA000491
CEH Sections/Science Areas: Hydro-climate Risks (Science Area 2017-)
ISSN: 2333-5084
Additional Information. Not used in RCUK Gateway to Research.: Open Access paper - full text available via Official URL link.
Additional Keywords: convection‐permitting modelling, precipitation, West Africa, storm tracking
NORA Subject Terms: Meteorology and Climatology
Date made live: 14 May 2019 15:21 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/523333

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