Characteristic aerosol optical depths during the Harmattan Season on sub‐Sahara Africa

Aerosol optical depths were derived from sun photometer measurements in three narrow bands centered at 500, 675 and 875 nm, taken at Ilorin, Nigeria, located in sub‐Saharan Africa. Selected results will be presented on the diurnal, seasonal, and interannual variability of spectral aerosol optical depth for two Harmattan seasons, during 1987–1989. At 500 nm values between 0.9–1.6 were quite common while the averages were between 1–1.2.