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Monitoring the Dynamics and Environmental Effects of West African Line Squall Using Satellite Imageries

Year: 2025

Type: article

Abstract: This study investigates the dynamics and environmental impacts of West African squall lines using geostationary satellite imagery. A case study of a mesoscale convective system (MCS) that propagated across the Gulf of Guinea–Sahel corridor from 5–7 May 2008 was analyzed using Meteosat Second Generation (MSG) RGB frames at six-hourly intervals (0000, 0600, 1200, 1800 UTC). Storm positions were tracked to estimate propagation speeds and assess lifecycle phases in relation to diurnal forcing and synoptic steering. Results show a characteristic diurnal cycle, with afternoon invigoration (15–18 UTC), nocturnal maintenance, and morning decay (09–12 UTC). Propagation speeds ranged from ~5 m s⁻¹ during organization and decay to ~21 m s⁻¹ during mature phases, consistent with movement near the African Easterly Jet (AEJ). As the system approached the Gulf of Guinea, coastal friction and marine boundary-layer interactions induced westward veering and slowing. Environmental effects included severe gusts (>15–20 m s⁻¹), dust squalls reducing visibility below 1 km, short-duration heavy rainfall (30–50 mm h⁻¹), flash flooding, and localized infrastructure damage. These findings reaffirm that although squall-line MCSs represent a minority of convective systems, they contribute a disproportionate share of Sahel rainfall (50–90% in some areas) and pose substantial short-lead hazards. The study further highlights the operational importance of the Meteosat Third Generation (MTG-I1), whose Flexible Combined Imager (FCI) and forthcoming Lightning Imager significantly enhance convective initiation detection, cold-cloud-top monitoring, and gust-front visualization. Integrating MTG products into forecasting workflows, supported by enhanced ground-based observations and hazard-based warning tools, is recommended to strengthen nowcasting capacity and reduce vulnerability to high-impact convective weather across West Africa

Source: Zenodo (CERN European Organization for Nuclear Research)

DOI: 10.5281/zenodo.17552834

Authors: Dr. Onyia, Anthonia Nkeiruka, Ijomah, Jude Obinna

Institutions: Enugu State University of Science and Technology, Federal Polytechnic Ohodo

Language: English

Topic: Meteorological Phenomena and Simulations

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDGs: Climate action, Industry, innovation and infrastructure

Open Access status: green

OpenAlex ID: W7104362198

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