scholarly journals Mesoscale water cycle within the West African Monsoon

2011 ◽  
Vol 12 (1) ◽  
pp. 45-50 ◽  
Author(s):  
C. Peugeot ◽  
F. Guichard ◽  
O. Bock ◽  
D. Bouniol ◽  
M. Chong ◽  
...  
Keyword(s):  
Water Cycle ◽  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon

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 The large-scale water cycle of the West African monsoon

2010 ◽  
Vol 12 (1) ◽  
pp. 51-57 ◽  
Author(s):  
O. Bock ◽  
F. Guichard ◽  
R. Meynadier ◽  
S. Gervois ◽  
A. Agustí-Panareda ◽  
...  
Keyword(s):  
Large Scale ◽  
Water Cycle ◽  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon

scholarly journals On What Scale Can We Predict the Agronomic Onset of the West African Monsoon?

2016 ◽  
Vol 144 (4) ◽  
pp. 1571-1589 ◽  
Author(s):  
Rory G. J. Fitzpatrick ◽  
Caroline L. Bain ◽  
Peter Knippertz ◽  
John H. Marsham ◽  
Douglas J. Parker
Keyword(s):  
West Africa ◽  
Noise Analysis ◽  
West African Monsoon ◽  
West African ◽  
New Method ◽  
The West ◽  
African Monsoon ◽  
Spatial Consistency ◽  
Local Stakeholders ◽  
Local Rainfall

Abstract Accurate prediction of the commencement of local rainfall over West Africa can provide vital information for local stakeholders and regional planners. However, in comparison with analysis of the regional onset of the West African monsoon, the spatial variability of the local monsoon onset has not been extensively explored. One of the main reasons behind the lack of local onset forecast analysis is the spatial noisiness of local rainfall. A new method that evaluates the spatial scale at which local onsets are coherent across West Africa is presented. This new method can be thought of as analogous to a regional signal against local noise analysis of onset. This method highlights regions where local onsets exhibit a quantifiable degree of spatial consistency (denoted local onset regions or LORs). It is found that local onsets exhibit a useful amount of spatial agreement, with LORs apparent across the entire studied domain; this is in contrast to previously found results. Identifying local onset regions and understanding their variability can provide important insight into the spatial limit of monsoon predictability. While local onset regions can be found over West Africa, their size is much smaller than the scale found for seasonal rainfall homogeneity. A potential use of local onset regions is presented that shows the link between the annual intertropical front progression and local agronomic onset.

scholarly journals A Lagrangian perspective on stable water isotopes during the West African Monsoon

2021 ◽  
Author(s):  
Christopher Johannes Diekmann ◽  
Matthias Schneider ◽  
Peter Knippertz ◽  
Andries Jan de Vries ◽  
Stephan Pfahl ◽  
...  
Keyword(s):  
West African Monsoon ◽  
West African ◽  
Water Isotopes ◽  
Stable Water Isotopes ◽  
The West ◽  
African Monsoon

A hydrological onset and withdrawal index for the West African monsoon

2008 ◽  
Vol 96 (1-2) ◽  
pp. 179-189 ◽  
Author(s):  
G. A. Dalu ◽  
M. Gaetani ◽  
M. Baldi
Keyword(s):  
West African Monsoon ◽  
West African ◽  
The West ◽  
African Monsoon

scholarly journals Coupled Land–Atmosphere Intraseasonal Variability of the West African Monsoon in a GCM

2010 ◽  
Vol 23 (21) ◽  
pp. 5557-5571 ◽  
Author(s):  
Sally L. Lavender ◽  
Christopher M. Taylor ◽  
Adrian J. Matthews
Keyword(s):  
Soil Moisture ◽  
Sensible Heat Flux ◽  
Intraseasonal Variability ◽  
West African Monsoon ◽  
Atmospheric Model ◽  
West African ◽  
The West ◽  
African Monsoon ◽  
Surface Sensible Heat Flux ◽  
Fully Coupled

Abstract Recent observational studies have suggested a role for soil moisture and land–atmosphere coupling in the 15-day westward-propagating mode of intraseasonal variability in the West African monsoon. This hypothesis is investigated with a set of three atmospheric general circulation model experiments. 1) When soil moisture is fully coupled with the atmospheric model, the 15-day mode of land–atmosphere variability is clearly identified. Precipitation anomalies lead soil moisture anomalies by 1–2 days, similar to the results from satellite observations. 2) To assess whether soil moisture is merely a passive response to the precipitation, or an active participant in this mode, the atmospheric model is forced with a 15-day westward-propagating cycle of regional soil moisture anomalies based on the fully coupled mode. Through a reduced surface sensible heat flux, the imposed wet soil anomalies induce negative low-level temperature anomalies and increased pressure (a cool high). An anticyclonic circulation then develops around the region of wet soil, enhancing northward moisture advection and precipitation to the west. Hence, in a coupled framework, this soil moisture–forced precipitation response would provide a self-consistent positive feedback on the westward-propagating soil moisture anomaly and implies an active role for soil moisture. 3) In a final sensitivity experiment, soil moisture is again externally prescribed but with all intraseasonal fluctuations suppressed. In the absence of soil moisture variability there are still pronounced surface sensible heat flux variations, likely due to cloud changes, and the 15-day westward-propagating precipitation signal is still present. However, it is not as coherent as in the previous experiments when interaction with soil moisture was permitted. Further examination of the soil moisture forcing experiment in GCM experiment 2 shows that this precipitation mode becomes phase locked to the imposed soil moisture anomalies. Hence, the 15-day westward-propagating mode in the West African monsoon can exist independently of soil moisture; however, soil moisture and land–atmosphere coupling act to feed back on the atmosphere and further enhance and organize it.

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