  Motivated by the important role of the ocean in the Earth climate system,
here we investigate possible scenarios of ocean circulations on exoplanets
using a one-layer shallow water ocean model. Specifically, we investigate how
planetary rotation rate, wind stress, fluid eddy viscosity and land structure
(a closed basin vs. a reentrant channel) influence the pattern and strength of
wind-driven ocean circulations. The meridional variation of the Coriolis force,
arising from planetary rotation and the spheric shape of the planets, induces
the western intensification of ocean circulations. Our simulations confirm that
in a closed basin, changes of other factors contribute to only enhancing or
weakening the ocean circulations (e.g., as wind stress decreases or fluid eddy
viscosity increases, the ocean circulations weaken, and vice versa). In a
reentrant channel, just as the Southern Ocean region on the Earth, the ocean
pattern is characterized by zonal flows. In the quasi-linear case, the
sensitivity of ocean circulations characteristics to these parameters is also
interpreted using simple analytical models. This study is the preliminary step
for exploring the possible ocean circulations on exoplanets, future work with
multi-layer ocean models and fully coupled ocean-atmosphere models are required
for studying exoplanetary climates.
