Currents generated by the sea breeze in the southern Caspian Sea

Abstract

The sea breeze system is the dominant atmospheric forcing at high frequency in the southern Caspian Sea. Here, we describe and interpret current meter observations on the continental margins of the southern Caspian from 2012 to 2013 to identify and characterize the water column's response to the sea breeze system. Time series analysis provides evidence for diurnal baroclinic current signals of O(0.02 m s−1) and surface height changes of O(0.03 m). A two-layer model, including interfacial and bottom friction, is developed to further investigate the sea breeze response. This model is able to reproduce the structure, amplitudes, and phases of observed diurnal current fluctuations, explaining half of the variance in observational current response at frequencies at 1 cpd and higher. The sea breeze response thus results in a “tide-like” daily cycle, which is actually linked to the local forcing all along the southern Caspian coast.