Travelling to two different Schengen countries for more than 90 days with a 10-day gap

Question

I am a student and I have planned academic trips on the following dates in the following countries:

• 11 August 2018 to 20 August 2018 in Dresden, Germany. (9 days)
• 1 September 2018 to 28 November 2018 in Copenhagen, Denmark. (88 days)

I want to know if I should apply for two different Schengen visas or I for one long-term visa, which will cover both trips.

In the latter case, when I am applying for a long-term visa, Hlhow do I justify support and explain I will be coming back. And which embassy to apply to?

EDIT1: Looking at the visa constraints, I have shifted my second visit to the end of the first visit so that I enter Europe once.

Now I am wondering if I should reduce my second visit to 80 days, so that I will have to take only one Schengen visa for 90 days and I will stay in Germany for 10 days and in Copenhagen for the next 80 days.

Is there any other way to get a 100-day visa for Europe?

Answer 1

Since your stay will involve visiting the Schengen area for more than 90 days in a 180 day period, you will need to apply for a long term (D type) visa from one of the countries you're visiting.

Whether or not you're eligible for one depends on the exact purpose of your visit and the documentation you have, so we can't help you out without seeing those.