Inertial currents in the Caspian Sea

James Farley Nicholls, Ralf Toumi and Paul Budgell. Imperial College London.

We present the first simulation of near-inertial oscillations in the Caspian Sea, where inertial waves are shown to be important in modeling the dynamics. The ROMS model is run over the enclosed Caspian Sea, where model inertial currents are in good agreement with observations. Annual mean near-inertial oscillations are found to be up to 14 cm/s with a seasonal maximum in the summer approximately twice as much as in the winter; a greater seasonal variation than observed elsewhere.

The energy increases away from the coast. The peak amplitude also occurs later as a function of distance from the coastline, with a delay on the order of 1 day per 100 km. These features are consistent with propagating baroclinic and barotropic waves and the mechanism proposed by Kundu et al. [1983] and Shearman [2005].