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Vegetation-climate feedbacks modulate rainfall patterns in Africa under future climate change

Wu, Minchao LU ; Schurgers, Guy LU ; Rummukainen, Markku LU ; Smith, Benjamin LU ; Samuelsson, Patrick; Jansson, Christer; Siltberg, Joe LU and May, Wilhelm LU (2016) In Earth System Dynamics 7(3). p.627-647
Abstract

Africa has been undergoing significant changes in climate and vegetation in recent decades, and continued changes may be expected over this century. Vegetation cover and composition impose important influences on the regional climate in Africa. Climate-driven changes in vegetation structure and the distribution of forests versus savannah and grassland may feed back to climate via shifts in the surface energy balance, hydrological cycle and resultant effects on surface pressure and larger-scale atmospheric circulation. We used a regional Earth system model incorporating interactive vegetation-atmosphere coupling to investigate the potential role of vegetation-mediated biophysical feedbacks on climate dynamics in Africa in an RCP8.5-based... (More)

Africa has been undergoing significant changes in climate and vegetation in recent decades, and continued changes may be expected over this century. Vegetation cover and composition impose important influences on the regional climate in Africa. Climate-driven changes in vegetation structure and the distribution of forests versus savannah and grassland may feed back to climate via shifts in the surface energy balance, hydrological cycle and resultant effects on surface pressure and larger-scale atmospheric circulation. We used a regional Earth system model incorporating interactive vegetation-atmosphere coupling to investigate the potential role of vegetation-mediated biophysical feedbacks on climate dynamics in Africa in an RCP8.5-based future climate scenario. The model was applied at high resolution (0.44 × 0.44°) for the CORDEX-Africa domain with boundary conditions from the CanESM2 general circulation model. We found that increased tree cover and leaf-area index (LAI) associated with a CO2 and climate-driven increase in net primary productivity, particularly over subtropical savannah areas, not only imposed important local effect on the regional climate by altering surface energy fluxes but also resulted in remote effects over central Africa by modulating the land-ocean temperature contrast, Atlantic Walker circulation and moisture inflow feeding the central African tropical rainforest region with precipitation. The vegetation-mediated feedbacks were in general negative with respect to temperature, dampening the warming trend simulated in the absence of feedbacks, and positive with respect to precipitation, enhancing rainfall reduction over the rainforest areas. Our results highlight the importance of accounting for vegetation-atmosphere interactions in climate projections for tropical and subtropical Africa.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Earth System Dynamics
volume
7
issue
3
pages
21 pages
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • scopus:84979901965
  • wos:000382829300001
ISSN
2190-4979
DOI
10.5194/esd-7-627-2016
language
English
LU publication?
yes
id
2081de9e-ae85-4bbe-b161-cba13c15c826
date added to LUP
2016-10-11 17:18:46
date last changed
2017-11-05 05:07:58
@article{2081de9e-ae85-4bbe-b161-cba13c15c826,
  abstract     = {<p>Africa has been undergoing significant changes in climate and vegetation in recent decades, and continued changes may be expected over this century. Vegetation cover and composition impose important influences on the regional climate in Africa. Climate-driven changes in vegetation structure and the distribution of forests versus savannah and grassland may feed back to climate via shifts in the surface energy balance, hydrological cycle and resultant effects on surface pressure and larger-scale atmospheric circulation. We used a regional Earth system model incorporating interactive vegetation-atmosphere coupling to investigate the potential role of vegetation-mediated biophysical feedbacks on climate dynamics in Africa in an RCP8.5-based future climate scenario. The model was applied at high resolution (0.44 × 0.44°) for the CORDEX-Africa domain with boundary conditions from the CanESM2 general circulation model. We found that increased tree cover and leaf-area index (LAI) associated with a CO<sub>2</sub> and climate-driven increase in net primary productivity, particularly over subtropical savannah areas, not only imposed important local effect on the regional climate by altering surface energy fluxes but also resulted in remote effects over central Africa by modulating the land-ocean temperature contrast, Atlantic Walker circulation and moisture inflow feeding the central African tropical rainforest region with precipitation. The vegetation-mediated feedbacks were in general negative with respect to temperature, dampening the warming trend simulated in the absence of feedbacks, and positive with respect to precipitation, enhancing rainfall reduction over the rainforest areas. Our results highlight the importance of accounting for vegetation-atmosphere interactions in climate projections for tropical and subtropical Africa.</p>},
  author       = {Wu, Minchao and Schurgers, Guy and Rummukainen, Markku and Smith, Benjamin and Samuelsson, Patrick and Jansson, Christer and Siltberg, Joe and May, Wilhelm},
  issn         = {2190-4979},
  language     = {eng},
  number       = {3},
  pages        = {627--647},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Earth System Dynamics},
  title        = {Vegetation-climate feedbacks modulate rainfall patterns in Africa under future climate change},
  url          = {http://dx.doi.org/10.5194/esd-7-627-2016},
  volume       = {7},
  year         = {2016},
}