Complex weather patterns in West Africa

Decoding West Africa's Weather: A Surprising Guide to Monsoons, Dust, and City Smog

Reese Marlowe in Climate & Environment August 2025 • 4 min read.

"Explore the hidden weather patterns of West Africa in 2016, from monsoon shifts and dust to city smog using science!"

West Africa's atmosphere is a stage for many different climate events that are closely connected, such as the West African monsoon. This monsoon is greatly affected by the contrast in pressure between the cooler waters located in the eastern tropical Atlantic Ocean and the hot Saharan heat low. This affects rainfall and weather patterns of Africa.

The Atlantic Ocean's cold tongue causes a boost in stability around the equator, leading to weaker surface winds. Furthermore, the winds pick up because the differences in sea surface temperatures grow and generate a pressure gradient that draws in wind, which causes a big atmospheric shift.

The DACCIWA project was launched in June and July 2016, and shed light on West Africa's complex interactions between weather and pollution. Instruments on the ground and in the air recorded information such as temperature, and pollution.

What Large-Scale Conditions Were in Place?

The global weather in 2016 set the scene for West Africa’s local weather patterns. Specifically, there was a Pacific La Niña, an Atlantic El Niño, and unusually warm conditions in the eastern Mediterranean. Competing influences in the Mediterranean, these large climate events made it tough to determine how much rain would occur.

These warmer-than-usual waters affect wind and rainfall amounts, so scientists monitor them closely to figure out what could happen in the atmosphere. In West Africa, there were several key phases during June and July 2016:

Phase 1 (June 1-21): High dust concentrations and cyclonic storms affected rainfall in coastal Guinea.
Phase 2 (June 22-July 20): A break in the Saharan heat low occurred because of an unusual trough and cold weather patterns coming from the north, which made storms that looked like tropical disturbances happen.
Phase 3 (July 21-26): The area experienced high westerly winds with humidity that created wet conditions and carried a lot of biomass burning pollution from Central Africa.
Phase 4 (July 27-31): The region returned to its normal weather conditions.

During the transitions between these phases, West Africa faced significant meteorological changes and shifts in air and water temperatures. When the monsoon changes from its pre-stage into full swing it impacts all atmospheric conditions.

Why Further Study Matters

The DACCIWA campaign highlights the complex interplay of climate factors and atmospheric conditions in West Africa. Through detailed analysis and data collection, the project advances weather research while also revealing important information regarding dust levels, biomass burning, and levels of pollution in cities.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.5194/acp-17-10893-2017, Alternate LINK

Title: A Meteorological And Chemical Overview Of The Dacciwa Field Campaign In West Africa In June–July 2016

Subject: Atmospheric Science

Journal: Atmospheric Chemistry and Physics

Publisher: Copernicus GmbH

Authors: Peter Knippertz, Andreas H. Fink, Adrien Deroubaix, Eleanor Morris, Flore Tocquer, Mat J. Evans, Cyrille Flamant, Marco Gaetani, Christophe Lavaysse, Celine Mari, John H. Marsham, Rémi Meynadier, Abalo Affo-Dogo, Titike Bahaga, Fabien Brosse, Konrad Deetz, Ridha Guebsi, Issaou Latifou, Marlon Maranan, Philip D. Rosenberg, Andreas Schlueter

Published: 2017-09-14

Everything You Need To Know

What is the DACCIWA project, and how did it help in understanding West Africa's weather in 2016?

The Dynamics-Aerosol-Chemistry-Cloud Interactions (DACCIWA) field campaign, launched in June and July 2016, was designed to investigate the complex interactions between weather and pollution in West Africa. It used instruments on the ground and in the air to record data such as temperature and pollution, shedding light on the connection between the West African monsoon, dust levels, biomass burning, and urban pollution. It helped advance weather research, revealing important information regarding atmospheric conditions.

How does the West African monsoon affect the region's weather patterns, and what role do ocean temperatures play?

The West African monsoon significantly influences rainfall and overall weather patterns. It's driven by pressure differences between the cooler waters of the eastern tropical Atlantic Ocean and the hot Saharan heat low. The Atlantic Ocean's cold tongue enhances stability around the equator, weakening surface winds. Increasing sea surface temperature differences generate a pressure gradient that pulls in wind, leading to atmospheric shifts. These oceanic factors exert considerable influence on the strength and timing of the monsoon, with consequent effects on regional precipitation.

What were the key phases observed during the West African monsoon in June and July 2016, and what characterized each phase?

During June and July 2016, the West African monsoon exhibited four distinct phases. Phase 1 (June 1-21) was marked by high dust concentrations and cyclonic storms affecting rainfall in coastal Guinea. Phase 2 (June 22-July 20) featured a break in the Saharan heat low caused by a trough and cold weather patterns from the north, leading to tropical disturbance-like storms. Phase 3 (July 21-26) experienced high westerly winds with humidity and biomass burning pollution from Central Africa. Phase 4 (July 27-31) saw a return to normal weather conditions. Transitions between these phases brought significant meteorological changes and shifts in air and water temperatures.

What impact did global weather phenomena like La Niña and Atlantic El Niño have on West Africa's weather patterns in 2016?

In 2016, global weather phenomena, including a Pacific La Niña, an Atlantic El Niño, and unusually warm conditions in the eastern Mediterranean, influenced West Africa's local weather patterns. These warmer-than-usual waters affect wind and rainfall amounts. The Mediterranean influences competed with each other, making it difficult to predict rainfall amounts accurately. Monitoring these large-scale climate events is crucial for anticipating their potential effects on the atmosphere and subsequent weather conditions in West Africa.

Why is it important to further study the interplay of climate factors and atmospheric conditions in West Africa, as highlighted by the DACCIWA campaign?

Further study of climate factors and atmospheric conditions in West Africa, as emphasized by the Dynamics-Aerosol-Chemistry-Cloud Interactions (DACCIWA) campaign, is crucial for several reasons. West Africa's atmosphere is influenced by diverse, interconnected climate events such as the West African monsoon, dust events, biomass burning, and urban pollution. Understanding these complex interactions helps advance weather research, refine forecasting models, and reveal the impacts of these factors on weather patterns. This knowledge contributes to better predictions of the monsoon's behavior, dust storms, and pollution events, which can assist in mitigating their potential impacts on agriculture, health, and regional stability.