Relationship between the Persian Gulf Sea-Level Fluctuations and Meteorological Forcing

Naghmeh Afshar-Kaveh,Mostafa Nazarali,Charitha Pattiaratchi

doi:10.3390/jmse8040285

Abstract

Sea-level data from six tide gauge stations along the northern coast of the Persian Gulf were analyzed both in time and frequency domain to evaluate meteorological forcing. Spectral analyses indicated that mixed, predominantly semi-diurnal tides were dominant at all stations, but low-frequency fluctuations correlated well with atmospheric pressure and wind components. Non-tidal sea-level fluctuations up to 0.75 m were observed along the northern coasts of the Gulf due to the combined action of lower atmospheric pressure and cross-shore wind. Coherency between low-frequency sea-level records and mean sea-level pressure indicated that the latter usually leads to sea-level fluctuations between 1 and 6.4 days. In contrast, the same analysis on the wind velocity and sea level revealed that the former lags between 3 and 13 days. The effect of wind stress on coastal sea-level variations was higher compared with the effect of atmospheric pressure. Concurrent analysis of low-pass-filtered sea-level records proved that the non-tidal wave moves from west to east along the northern coasts of the Persian Gulf.

Highlights

Coastal regions experience sea-level fluctuations occurring over different time scales from seconds to centuries
The relative importance of air pressure and winds in sea-level variability depends on the location and time scale [3]
The sea surface will rise in response to a drop in local air pressure, and vice versa, which is called the local inverse barometer (LIB)

Summary

Introduction

Coastal regions experience sea-level fluctuations occurring over different time scales from seconds to centuries. Sea-level variability (SLV) in response to wind and atmospheric pressure change has been extensively studied for different water bodies around the world [5,6,7]. They are considered to be meso-scale phenomena both temporally and spatially [8]. One of the most recent destructive events in the region was recorded on 19 March 2017 This was a meteorological tsunami [15] that hit the shorelines of Dayyer coastal city along the northern coast of the Gulf [16]. The coherency between these forces is described both in time and frequency domains

Study Area

Wavelet Analysis