A system of converging, relatively dry air that slowly descends, it warms by compression. This subsiding air produces generally clear skies and warm surface temperatures; hence, on earth it is here that we find the major deserts of the world, such as the Sahara of Africa and the Sonoran of North America :
(A) Inter tropical convergence zone
(B) Subtropical High
(C) Polar easterlies
(D) SE Trade winds