subaerial
adjective
sub·aer·i·al ˌsəb-ˈer-ē-əl 
-ā-ˈir-ē-əl
: situated, formed, or occurring on or immediately adjacent to the surface of the earth
subaerial erosion
subaerial roots
subaerially
ˌsəb-ˈer-ē-ə-lē
adverb -ā-ˈir-ē-ə-lē
Example Sentences
Recent Examples on the Web Submarine areas under US control out to the 200 mile limit are equal to the subaerial land area of this great nation, and yet the seabed resources have yet to be explored and inventoried. 
Brian Romans, WIRED, 8 Oct. 2009
Brian Romans, WIRED, 8 Oct. 2009 Word History
First Known Use
1726, in the meaning defined above