“…Comprehensive mathematical models that handle wave-current interactions and internal waves in the presence of density stratification within the setting of nonlinear geophysical governing equations are quite rare and of very recent date [5, 8-10, 15, 17,34]. The stratification issue alone, in spite of being of utmost practical relevance, has remained unamenable to a rigorous mathematical analysis until recently: for a selection of recent advances in the field (in the scenario of two-dimensional gravity water waves without Earth's rotation effects) we refer the reader to [9,10,15,18,19,25,26,46,51,52].…”