On periodic water waves with Coriolis effects and isobaric streamlines
  In this paper we prove that solutions of the f-plane approximation for equatorial geophysical deep water waves, which have the property that the pressure is constant along the streamlines and do not possess stagnation points,are Gerstner-type waves. Furthermore, for waves traveling over a flat bed, we prove that there are only laminar flow solutions with these properties. 
Anca-Voichita Matioc and Bogdan-Vasile Matioc
math.AP