Where does the harmattan wind come from?

The harmattan is a cool, dry trade wind that originates from the northeast or east in the western Sahara.1

This wind is driven by a high-pressure centre located over northwestern Africa during the winter months, which interacts with a low-pressure centre situated over the north coast of the Gulf of Guinea. As it blows across the region, it frequently carries large quantities of dust and sand, which can be transported hundreds of kilometres over the Atlantic Ocean.12