scholarly journals The role of moist convection in the West African monsoon system: Insights from continental-scale convection-permitting simulations

2013 ◽  
Vol 40 (9) ◽  
pp. 1843-1849 ◽  
Author(s):  
John H. Marsham ◽  
Nick S. Dixon ◽  
Luis Garcia-Carreras ◽  
Grenville M. S. Lister ◽  
Douglas J. Parker ◽  
...  
Keyword(s):  
West African Monsoon ◽  
West African ◽  
Moist Convection ◽  
The West ◽  
African Monsoon ◽  
Continental Scale ◽  
Monsoon System

scholarly journals Supplementary material to "The role of low-level clouds in the West African monsoon system"

2018 ◽  
Author(s):  
Anke Kniffka ◽  
Peter Knippertz ◽  
Andreas H. Fink
Keyword(s):  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon ◽  
Low Level ◽  
Monsoon System ◽  
Supplementary Material

scholarly journals A seamless assessment of the role of convection in the water cycle of the West African Monsoon

2014 ◽  
Vol 119 (6) ◽  
pp. 2890-2912 ◽  
Author(s):  
C. E. Birch ◽  
D. J. Parker ◽  
J. H. Marsham ◽  
D. Copsey ◽  
L. Garcia-Carreras
Keyword(s):  
Water Cycle ◽  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon

scholarly journals Decadal and multi-year predictability of the West African monsoon and the role of dynamical downscaling

2017 ◽  
Vol 26 (4) ◽  
pp. 363-377 ◽  
Author(s):  
Heiko Paeth ◽  
Andreas Paxian ◽  
Dmitry V. Sein ◽  
Daniela Jacob ◽  
Hans-Jürgen Panitz ◽  
...  
Keyword(s):  
Dynamical Downscaling ◽  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon

The role of the Indian monsoon onset in the West African monsoon onset: observations and AGCM nudged simulations

2011 ◽  
Vol 38 (5-6) ◽  
pp. 965-983 ◽  
Author(s):  
Emmanouil Flaounas ◽  
Serge Janicot ◽  
Sophie Bastin ◽  
Rémy Roca ◽  
Elsa Mohino
Keyword(s):  
Indian Monsoon ◽  
West African Monsoon ◽  
Monsoon Onset ◽  
West African ◽  
The West ◽  
African Monsoon

scholarly journals Seasonal Evolution and Variability Associated with the West African Monsoon System

2004 ◽  
Vol 17 (17) ◽  
pp. 3364-3377 ◽  
Author(s):  
Guojun Gu ◽  
Robert F. Adler
Keyword(s):  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon ◽  
Seasonal Evolution ◽  
Monsoon System

scholarly journals The effect of explicit convection on climate change in the West African monsoon and central West African Sahel rainfall

2021 ◽  
pp. 1-42
Keyword(s):  
Climate Change ◽  
West African Monsoon ◽  
West African ◽  
Annual Rainfall ◽  
Moist Convection ◽  
The West ◽  
African Monsoon ◽  
Dominant Feature ◽  
West African Sahel ◽  
African Sahel

Abstract The West African monsoon (WAM) is the dominant feature of West African climate providing the majority of annual rainfall. Projections of future rainfall over the West African Sahel are deeply uncertain with a key reason likely to be moist convection, which is typically parameterized in global climate models. Here, we use a pan-Africa convection permitting simulation (CP4), alongside a parameterized convection simulation (P25), to determine the key processes that underpin the effect of explicit convection on the climate change of the central West African Sahel (8°W-2°E, 12-17°N). In current climate, CP4 affects WAM processes on multiple scales compared to P25. There are differences in the diurnal cycles of rainfall, moisture convergence, and atmospheric humidity. There are upscale impacts: the WAM penetrates farther north, there is greater humidity over the north Sahel and the Saharan heat low regions, the sub-tropical subsidence rate over the Sahara is weaker, and ascent within the tropical rain belt is deeper. Under climate change, the WAM shifts northwards and Hadley circulation weakens in P25 and CP4. The differences between P25 and CP4 persist, however, underpinned by process differences at the diurnal and large-scales. Mean rainfall increases 17.1% in CP4 compared to 6.7% in P25 and there is greater weakening in tropical ascent and sub-tropical subsidence in CP4. These findings show the limitations of parameterized convection and demonstrate the value that explicit convection simulations can provide to climate modellers and climate policy decision makers.

scholarly journals The role of low-level clouds in the West African monsoon system

2019 ◽  
Vol 19 (3) ◽  
pp. 1623-1647 ◽  
Author(s):  
Anke Kniffka ◽  
Peter Knippertz ◽  
Andreas H. Fink
Keyword(s):  
Climate Models ◽  
West African Monsoon ◽  
West African ◽  
Surface Radiation ◽  
Boreal Summer ◽  
The West ◽  
African Monsoon ◽  
Low Level ◽  
Low Clouds ◽  
Monsoon System

Abstract. Realistically simulating the West African monsoon system still poses a substantial challenge to state-of-the-art weather and climate models. One particular issue is the representation of the extensive and persistent low-level clouds over southern West Africa (SWA) during boreal summer. These clouds are important in regulating the amount of solar radiation reaching the surface, but their role in the local energy balance and the overall monsoon system has never been assessed. Based on sensitivity experiments using the ICON model for July 2006, we show for the first time that rainfall over SWA depends logarithmically on the optical thickness of low clouds, as these control the diurnal evolution of the planetary boundary layer, vertical stability and finally convection. In our experiments, the increased precipitation over SWA has a small direct effect on the downstream Sahel, as higher temperatures due to increased surface radiation are accompanied by decreases in low-level moisture due to changes in advection, leading to almost unchanged equivalent potential temperatures in the Sahel. A systematic comparison of simulations with and without convective parameterization reveals agreement in the direction of the precipitation signal but larger sensitivity for explicit convection. For parameterized convection the main rainband is too far south and the diurnal cycle shows signs of unrealistic vertical mixing, leading to a positive feedback on low clouds. The results demonstrate that relatively minor errors, variations or trends in low-level cloudiness over SWA can have substantial impacts on precipitation. Similarly, they suggest that the dimming likely associated with an increase in anthropogenic emissions in the future would lead to a decrease in summer rainfall in the densely populated Guinea coastal area. Future work should investigate longer-term effects of the misrepresentation of low clouds in climate models, e.g. moderated through effects on rainfall, soil moisture and evaporation.

scholarly journals Characteristics of wet and dry spells in the West African monsoon system

2017 ◽  
Vol 18 (3) ◽  
pp. 125-131 ◽  
Author(s):  
Stéphanie Froidurot ◽  
Arona Diedhiou
Keyword(s):  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon ◽  
Dry Spells ◽  
Monsoon System
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