Adjective
Beneath the sky; in the open air; specifically (Geol.), taking place on the earth's surface, as opposed to subaqueous.
Source: Webster's dictionaryThey have been formed since the Minoan eruption, and the first of them broke the surface of the sea in 197 BC Nine subaerial eruptions are recorded in the historical record since that time, with the most recent ending in 1950. Source: Internet
This part of the mid-ocean ridge is located above a mantle plume, causing Iceland to be subaerial (above the surface of the sea). Source: Internet