  A micro-macro variant of the parallel-in-time algorithm Parareal has been
applied to the ocean-circulation and sea-ice model model FESOM2. The
state-of-the-art software in climate research has been developed by the
Alfred-Wegener-Institut (AWI) in Bremen, Germany. The algorithm requires two
meshes of low and high spatial resolution to define the coarse and fine
propagator. As a first assessment we refined the PI mesh, increasing its
resolution by factor 4. The main objective of this study was to demonstrate
that micro-macro Parareal can provide convergence in diagnostic variables in
complex climate research problems. After the introduction to FESOM2 we show how
to generate the refined mesh and which interpolation methods were chosen. With
the convergence results presented we discuss the success of this attempt and
which steps have to be taken to extend the approach to current research
problems.
