Internal tides on the Al-Batinah shelf: evolution, structure and predictability

Abstract. Internal tides are a key mechanism of energy transfer on continental shelves. We present observations of internal tides on the northern Oman shelf based on moored temperature and velocity records collected during summer 2022. The regional shelf exhibits strong summer stratification, supporting shoreward-propagating internal tides with pronounced fortnightly modulation in amplitude and energy fluxes. Despite semidiurnal dominance in barotropic forcing, the internal tides appear predominantly in the diurnal band. Waveform structures undergo transition from quasi-linear depression waves to increasingly nonlinear features, including steepening, asymmetry, and polarity reversal. Modal decomposition shows a shift toward first-mode dominance as the thermocline deepens seasonally. Cross-shelf coherence and phase-speed estimates confirm that the observed internal tides maintain spatial coherence from the shelf edge to the shallow inner shelf beyond the typical internal surf zone. Predictability skill scores indicate that the local internal tides are comparable to high-predictability sites globally while inshore directed energy flux, diurnal dominance and phase lags to barotropic forcing still indicate remote generation.