1) Geology terminology 
The term subaerial (literally `under the air`) is mainly used in geology to describe events or features that are formed, located or taking place on the Earth`s land surface and exposed to Earth`s atmosphere. This may be contrasted with subaqueous, events or features — located below a water surface, submarine events or features — located be...
in open air
• (a.) Beneath the sky; in the open air; specifically (Geol.), taking place on the earth`s surface, as opposed to subaqueous.
Sub`a·ë'ri·al adjective Beneath the sky; in the open air; specifically (Geol.) , taking place on the earth's surface, as opposed to subaqueous . 
Occurring beneath the atmosphere or in the open air, with reference to conditions or processes (such as erosion) that occur on the land. Contrast with submarine and subterranean.
located or occurring on the surface of the earth.