Jackson, LS orcid.org/0000-0001-8143-2777, Finney, DL, Kendon, EJ et al. (5 more authors) (2020) The effect of explicit convection on couplings between rainfall, humidity and ascent over Africa under climate change. Journal of Climate, 33 (19). pp. 8315-8337. ISSN 0894-8755
Abstract
The Hadley circulation and tropical rain belt are dominant features of African climate. Moist convection provides ascent within the rain belt, but must be parameterized in climate models, limiting predictions. Here, we use a pan-African convection-permitting model (CPM), alongside a parameterized convection model (PCM), to analyze how explicit convection affects the rain belt under climate change. Regarding changes in mean climate, both models project an increase in total column water (TCW), a widespread increase in rainfall, and slowdown of subtropical descent. Regional climate changes are similar for annual mean rainfall but regional changes of ascent typically strengthen less or weaken more in the CPM. Over a land-only meridional transect of the rain belt, the CPM mean rainfall increases less than in the PCM (5% vs 14%) but mean vertical velocity at 500 hPa weakens more (17% vs 10%). These changes mask more fundamental changes in underlying distributions. The decrease in 3-hourly rain frequency and shift from lighter to heavier rainfall are more pronounced in the CPM and accompanied by a shift from weak to strong updrafts with the enhancement of heavy rainfall largely due to these dynamic changes. The CPM has stronger coupling between intense rainfall and higher TCW. This yields a greater increase in rainfall contribution from events with greater TCW, with more rainfall for a given large-scale ascent, and so favors slowing of that ascent. These findings highlight connections between the convective-scale and larger-scale flows and emphasize that limitations of parameterized convection have major implications for planning adaptation to climate change.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 American Meteorological Society. This article is licensed under a Creative Commons Attribution 4.0 license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | Deep convection, Hadley circulation, Vertical motion, Climate change, Mixed precipitation, Convective parameterization |
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) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/M017176/1 EU - European Union 603502 NERC (Natural Environment Research Council) NE/M020126/1 NERC (Natural Environment Research Council) NE/M02038X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 Jun 2020 14:51 |
Last Modified: | 15 Oct 2021 09:26 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/JCLI-D-19-0322.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:161496 |