Annual and early summer variability in WRF-CHEM simulated West African PM10 during 1960–2016

Abstract

We examine annual PM10 concentrations across the Sahara and Sahel using the Weather, Research and Forecast (WRF) model with the GOCART dust module during 1960–2016 driven at the lateral boundaries with the NCEP reanalysis. We show that there is a simulated annual downward trend in surface PM10 concentrations in Senegal and Cabo Verde after the 1980s, which is similar to earlier findings. The analysis of simulated PM10 concentrations over the period of 1960–2016 during May, June and July (MJJ) suggests that there has been an increase in the vertical transport of dust over the Western Sahara which is then horizontally transported downstream at approximately 700 hPa for Cabo Verde. This suggests that dust transport to the Eastern Atlantic, which could be further transported downstream towards the Caribbean and United States, may have increased during the early 21st century.