Abstract
Properties of coastal flows of the central Red Sea are examined using 2 years of velocity data acquired off the coast of Saudi Arabia near 22°N. The tidal flow is found to be very weak. The strongest tidal constituent, the M2 tide, has a magnitude of order 4cms−1. Energetic near-inertial and diurnal period motions are observed. These are surface-intensified currents, reaching magnitudes of >10cms−1. Although the diurnal currents appear to be principally wind-driven, their relationship with the surface wind stress record is complex. Less than 50% of the diurnal current variance is related to the diurnal wind stress through linear correlation. Correlation analysis reveals a classical upwelling/downwelling response to the alongshore wind stress. However, less than 30% of the overall sub-inertial variance can be accounted for by this response. The action of basin-scale eddies, impinging on the coastal zone, is implicated as a primary mechanism for driving coastal flows.
•Red Sea coastal flows include tidal, near-inertial, and sea breeze-driven motions.•Tidal flows are dominated by the M2 tide and are weak, order 4cms−1.•Wind-driven upwelling/downwelling circulation is apparent.•Only 30% of sub-inertial flow variance is due to wind-driven motions.•Basin-scale eddies are implicated as a primary driver of coastal flows.