Investigation of Saharan Dust Transport Events Over Northern Nigeria

Saharan dust transport is a significant regional aerosol phenomenon with important consequences for solar radiation, air quality, and public health across West Africa. This study investigates the frequency, seasonality, and optical properties of Saharan dust transport events over northern Nigeria, with a focus on the states of Katsina, Zamfara, and Jigawa. Aerosol Optical Depth (AOD) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra satellite were analyzed for the period 2018 to 2023, complemented by backward trajectory analysis using the NOAA HYSPLIT model to confirm Saharan source regions. Surface meteorological records from NiMet stations were used to document surface-level manifestations including visibility reduction and dust deposition events. Results indicate that peak dust transport over northern Nigeria occurs between November and March, with AOD values averaging 0.82 during this period compared to 0.24 during the wet season. Trajectory analysis confirms that the majority of dust loadings originate from the Bodele Depression in Chad and the Mali Erg. A statistically significant positive correlation between dust event frequency and meningococcal disease incidence in Katsina State is documented, consistent with the established dust-meningitis hypothesis. The study recommends that NiMet expand its dust monitoring capacity through participation in the WMO Sand and Dust Storm Warning Advisory and Assessment System. Keywords: Saharan dust, aerosol optical depth, HYSPLIT, northern Nigeria, meningitis.