1. Average annual rainfall 1921-1950 (mm), Sudan Maps Stanford University Public content Sudan, Maṣlaḥat al-Arṣād al-Jawwīyah. and Sudan, Maṣlaḥat al-Misāḥah. prepared by Sudan Meteorological Service, July 1949. "Topo. No. S. 912 54.". Sudan Survey Dept.