noun, noun or participle which takes 'suru', intransitive verb
going upstream; swimming upstream
Used for fish or boats moving against the current of a river. Can also be used metaphorically for tracing back to origins.
鮭が川を遡上する季節になった。
It's the season when salmon swim upstream.
問題の原因を遡上
We trace back to the source of the problem and investigate.