an Auxiliary verb. Has nuance of 'moving up'...
Doing something up to a point of completion.
It implies that a lot of effort has been put in.
It is only used with a very limited set of verbs.
空が晴れ上がった。 The sky fully cleared up.
魚を釣り上げた。 To (fully) fish up a fish (implies you're holding it in your hands now)
彼女は歌い上げました The girl fully sang (she sang very loudly)
- 3時間で宿題の作文を書き上げた。
- 彼は素晴らしい芸術作品を作り上げた。