It's really the sun up there. This photo was taken on a particularly dusty morning somewhere east of Yankari Game Reserve in Bauchi State, Northern Nigeria.
The Harmattan is a dry and dusty West African trade wind. It blows south from the Sahara Desert into the Gulf of Guinea between the end of November and the middle of March. On its passage over the desert it picks up fine dust particles (between 0.5 and 10 micrometres). When the Harmattan blows hard, it can push dust and sand all the way across the Atlantic Ocean to the Caribbean and South America.
