tropical air Air masses whose characteristics originate from a tropical source. Broadly, these comprise: (a) maritime tropical air, originating over oceans; and (b) continental tropical air, originating over land masses, and especially over N. Africa and the Middle East. Movements of these air masses poleward, with modification of their original characteristics, can have marked influence on weather in mid-latitudes.

tropical air An air mass that acquires its characteristics in the tropics, as (a)maritime tropical air, originating over oceans; or(b)continental tropical air, originating over land masses (especially over North Africa and the Middle East). Movements of these air masses poleward, with modification of their original characteristics, can have marked influence on weather in mid-latitudes.