Hi Markus,
Your question about why Jupiter's clouds just don't all mix together into
a single homogeneous colour is a good one.
When I read it, it reminded me a of passage in a wonderful 1989 book
entitled
"The Cuckoo’s Egg: Tracking a Spy Through the Maze of
Computer Espionage" by
Clifford Stoll.
The book is a personal account by Stoll in tracking a computer hacker who
was gaining access to a computer that he was managing at the Lawrence
Berkeley National Laboratory.
The book itself is one of the most entertaining reads of the 20th Century
and is highly recommended.
By profession, Stoll was an astronomer. In the book he provides a hilarious
anecdote of appearing before an panel of professors who are assessing his
PhD dissertation.
All is going well when one of the professors asks, "Cliff, why is the sky blue?"
I just Googled and by luck there is this fabulous 2 minute 46 second
YouTube video from some years back when Stoll was interviewed by
the U.S. NBC network where he provides that account of the PhD interview.
I suspect like the question that Stoll is forced to try and answer in ever
increasing detail, the true answer to your question might well prove to
be as equally layered and complex
If you want a good laugh, I recommend this short video
:-
https://youtu.be/yfm3MFj6LLU
As a postscript I was lucky enough to meet a couple of visitors from the
US last year, one of whom was a retired professor of astronomy.
During conversation I mentioned the Stoll "why is the sky blue" story
and as it turned out they not only knew the story, they were also
friends of Clifford Stoll.
Which might beg the question, "Why is the world so small at times?"