This is the 17263rd most frequent Korean word.
서해상으로
"Toward the West Sea."
In this sentence, "서해상으로" refers to a direction or movement over the western sea.
폭풍이 서해상으로 접근하고 있습니다.
The storm is approaching over the western sea.
Here, "서해상으로" indicates a direction of travel toward the western sea.
그 배는 서해상으로 향했다.
The ship headed toward the western sea.
In this context, "서해상으로" depicts the origin or source direction of the sea breeze from the western sea.