Rainfall Variability and Trend Analysis of Rainfall in West Africa (Senegal, Mauritania, Burkina Faso)

This study concerns the West African Sahel. The Sahelian climate is characterized by a long dry season and a rainy season which starts in June and ends in September–October. This latter season is associated with the process of oceanic moisture transfer to the mainland (the West African Monsoon). This movement is governed by an overall moving of the meteorological equator and its low-pressure corridor (Intertropical Convergence Zone, ITCZ) towards the north, under the effect of the attraction of the Saharan thermal depressions and a greater vigor of the anticyclonic nuclei. This study was conducted on 27 Sahelian climatic stations in three countries (Burkina Faso, Mauritania, and Senegal). The method used to determine the modes of this variability and the trends of rainfall is the chronological graphic method of information processing (MGCTI) of the “Bertin Matrix” and continuous wavelets transform (CWT). Results show a rain resumption observed in the recent years over the Sahelian region and a convincing link with the surface temperature of the Atlantic Ocean.

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Woody Vegetation Die off and Regeneration in Response to Rainfall Variability in the West African Sahel

Remote Sensing ◽

10.3390/rs9010039 ◽

2017 ◽

Vol 9 (1) ◽

pp. 39 ◽

Cited By ~ 30

Author(s):

Martin Brandt ◽

Gray Tappan ◽

Abdoul Diouf ◽

Gora Beye ◽

Cheikh Mbow ◽

...

Keyword(s):

Rainfall Variability ◽

West African ◽

Woody Vegetation ◽

The West ◽

West African Sahel ◽

African Sahel

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

Journal of Climate ◽

10.1175/jcli-d-21-0258.1 ◽

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.

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Songhay Languages

The Oxford Handbook of African Languages ◽

10.1093/oxfordhb/9780199609895.013.77 ◽

2020 ◽

pp. 643-653

Author(s):

Lameen Souag

Keyword(s):

West African ◽

Language Group ◽

The West ◽

The North ◽

The Family ◽

Niger River ◽

Sahel Region ◽

West African Sahel ◽

African Sahel ◽

Contact Effects

Songhay is a language group of the West African Sahel region with more than four million speakers, distributed mainly in western Niger and northeastern Mali along the Niger River, but including outlying pockets scattered as far afield as Algeria, Ghana, and Sudan. Strong contact effects along the periphery—notably involving Berber in the north and Bariba and Hausa in the southeast, and Mande languages at an earlier stage—have resulted in a remarkable situation where different varieties may have nearly identical basic vocabularies but conspicuously different typologies. Cladistic and lexical evidence shows that much of the observed variation reflects contact influences quite different from those obtaining today. This chapter examines particularly morphology and syntax across the family. Special attention is given to innovations distinguishing the three principal subgroups (Eastern, Western, and Northern), and to the motivations for these changes.

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How Does Gender Affect Sustainable Intensification of Cereal Production in the West African Sahel? Evidence from Burkina Faso

World Development ◽

10.1016/j.worlddev.2016.12.003 ◽

2017 ◽

Vol 92 ◽

pp. 177-191 ◽

Cited By ~ 35

Author(s):

Veronique Theriault ◽

Melinda Smale ◽

Hamza Haider

Keyword(s):

Burkina Faso ◽

West African ◽

Sustainable Intensification ◽

The West ◽

Cereal Production ◽

West African Sahel ◽

African Sahel

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The West African Sahel: A Review of Recent Studies on the Rainfall Regime and Its Interannual Variability

ISRN Meteorology ◽

10.1155/2013/453521 ◽

2013 ◽

Vol 2013 ◽

pp. 1-32 ◽

Cited By ~ 280

Author(s):

Sharon E. Nicholson

Keyword(s):

Interannual Variability ◽

Land Surface ◽

Field Experiments ◽

West African Monsoon ◽

West African ◽

Rainfall Regime ◽

The West ◽

African Monsoon ◽

West African Sahel ◽

African Sahel

The West African Sahel is well known for the severe droughts that ravaged the region in the 1970s and 1980s. Meteorological research on the region has flourished during the last decade as a result of several major field experiments. This paper provides an overview of the results that have ensued. A major focus has been on the West African monsoon, a phenomenon that links all of West Africa. The characteristics and revised picture of the West African monsoon are emphasized. Other topics include the interannual variability of rainfall, the atmospheric circulation systems that govern interannual variability, characteristics of precipitation and convection, wave activity, large-scale factors in variability (including sea-surface temperatures), and land-atmosphere relationships. New paradigms for the monsoon and associated ITCZ and for interannual variability have emerged. These emphasize features in the upper atmosphere, as well as the Saharan Heat Low. Feedback mechanisms have also been emphasized, especially the coupling of convection with atmospheric dynamics and with land surface characteristics. New results also include the contrast between the premonsoon and peak monsoon seasons, two preferred modes of interannual variability (a latitudinal displacement of the tropical rainbelt versus changes in its intensity), and the critical importance of the Tropical Easterly Jet.

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