The Collaborative International Dictionary
Subaerial \Sub`a*["e]"ri*al\, a. Beneath the sky; in the open air; specifically (Geol.), taking place on the earth's surface, as opposed to subaqueous.
Wiktionary
a. (context geology English) Formed, located or occurring on the Earth's land surface; contrasted with subaqueous
Wikipedia
The term subaerial (literally "under the air"), first used in 1833, is mainly used in natural science, notably in geology and botany, to describe events or features that are formed, located or taking place immediately on or near the Earth's land surface. They are thus exposed to Earth's atmosphere. This may be contrasted with subaqueous events or features — located below a water surface, submarine events or features — located below a sea surface, or subglacial ones — located below glacial ice such as ice sheets.
Usage examples of "subaerial".
Vincent, during the last voyage of the vessel across the Atlantic, taken in connection with previous soundings obtained in the same region of the North Atlantic, suggests the probable existence of a submarine ridge or plateau connecting the island of Madeira with the coast of Portugal, and the probable subaerial connection in prehistoric times of that island with the south-western extremity of Europe.