Maritime air mass, vast body of air of oceanic origin; also, an air mass (q.v.) that has had a long trajectory over water and has been so modified that it has the characteristics of an air mass of oceanic origin
Maritime air masses form over water and are humid. Continental air masses form over land and are dry. Therefore, an air mass that develops over northern Canada is called a continental polar air mass and is cold and dry. One that forms over the Indian Ocean is called a maritime tropical air mass and is warm and humid.
