Reply on RC2

Şükrü Beşiktepe

doi:10.5194/os-2022-1-ac2

Abstract

Coastal trapped waves (CTW) were investigated in the Black Sea during 2012–2016 using observations from the sea level stations at five locations along the southern coast of the Black Sea together with the sea surface height model from Copernicus Marine Service. Spectral and wavelet analysis of sea level data shows that CTWs exist in the Black Sea with a period of 12–13 days and 15 days duration. These waves propagate from west to east with a speed of 2.3–2.6 m s−1 and cause 10–20 cm variability in sea level. To investigate formation mechanisms of CTWs, sea surface height and surface velocities from Copernicus Marine Service, wind measurements from sea level stations and atmospheric model results from Copernicus Marine Service are jointly analyzed. These analyses showed that CTWs were formed when water accumulated on the western shelf after gale force alongshore winds blowing in the western Black Sea. Our results provide clear observational evidence on process of the excitement of CTWs by wind stress. CTWs generate a coastal current reaching up to 0.5 m s−1. This coastal current joins to large-scale cyclonic inertial current flowing over the continental slope and accelerates it. Hence, we present evidence on the influence of the CTWs on the large scale circulation.

Highlights

The existence of trapped modes in certain cases was first discovered by Stokes (1846), who obtained trapped wave solution on fundamental mode edge waves on a sloping beach; these waves propagate in the longshore direction and their amplitude decays exponentially in the offshore direction
To investigate formation mechanisms of Coastal trapped waves (CTW), sea surface height and surface velocities from Copernicus Marine Service, wind measurements from sea level stations and atmospheric model results from Copernicus Marine Service are jointly analyzed. These analyses showed that CTWs were formed when water accumulated on the western 15 shelf after gale force alongshore winds blowing in the western Black Sea
6 Summary and Concluding Remarks Sea level measurements from five coastal stations situated in the southern Black Sea are analyzed to reveal low frequency oscillations in the basin

Summary

Introduction

The existence of trapped modes in certain cases was first discovered by Stokes (1846), who obtained trapped wave solution on fundamental mode edge waves on a sloping beach; these waves propagate in the longshore direction and their amplitude decays exponentially in the offshore direction. This theory was extended a century later by Ursell (1951) to include the whole spectrum of possible modes.

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Conclusion