With 100 - 400 mm of mean annual rainfall and high interannual rainfall variability, monthly potential evapora-tion (PE) can exceed annual rain.
Nicholson, S.E., J. Kim, and J. Hoopingarner, 1988. Atlas of African Rainfall and Its Interannual Variability. Department of Meteorology, Florida State University, Tallahassee, FL.
Mean annual rainfall (mm)
coefficient of variation of