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Wind shear effects in convection-permitting models influence MCS rainfall and forcing of tropical circulation
  • +7
  • Ben Maybee,
  • John Marsham,
  • Cornelia Klein,
  • Douglas J. Parker,
  • Emma Jane Barton,
  • Christopher M Taylor,
  • Huw Lewis,
  • Claudio Sanchez,
  • Richard Wilson Jones,
  • James Lewis Warner
Ben Maybee
University of Leeds

Corresponding Author:[email protected]

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John Marsham
University of Leeds
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Cornelia Klein
Centre for Ecology and Hydrology (CEH)
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Douglas J. Parker
University of Leeds
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Emma Jane Barton
Centre for Ecology and Hydrology
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Christopher M Taylor
UK Centre for Ecology and Hydrology
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Huw Lewis
Met Office
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Claudio Sanchez
Met Office
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Richard Wilson Jones
Met Office
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James Lewis Warner
UK Met Office
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Abstract

Mesoscale Convective Systems (MCSs) play a critical role in tropical rainfall patterns and circulations. To reduce persistent biases and improve understanding of the climate system, international groups have called for unprecedented investment in global convection-permitting (CP) climate models. It is essential such models accurately represent MCSs, and in particular environmental interactions such as dynamical control by wind shear. We show that in representative current generation CP simulations, MCS updraft entrainment decreases with shear, leading to a realistic increase of extreme rainfall. We find the control of environmental shear extends to mean storm rainfall and anvil heights. The simulation of these effects depends strongly on model physics in both CP and parameterised models. We show that in West Africa, MCS shear response influences the zonal distribution of storm diabatic heating, modifying upscale impacts of convection. Our results demonstrate key tests for focused process-based assessment of CP model fidelity.
28 Aug 2024Submitted to ESS Open Archive
29 Aug 2024Published in ESS Open Archive