Influence of sea level variability on a micro-tidal beach

Abstract

Global climate change in response to buildup of human-induced greenhouse gases in the atmosphere has already resulted in several visible consequences such as an increase in ocean heat content and melting of glaciers. The relative effect of sea level and wave variability on shoreline changes along the coastline of James Town, Ghana (Gulf of Guinea), was investigated between 2013 and 2014. Data were gathered at James Town, over an 8-month period (2013–2014) from nearshore video installation, Era-Interim hindcast, and satellite altimetry. Data were evaluated over daily and monthly timescale variations. Though beach changes are not directly driven by sea level variability, its action is key in modulating waves influence. The results show that the shoreline responds in decreasing order to sea level variations (86%), waves (9%), and tidal cycles (5%) on daily bases. Wind-induced setup has limited effect on the shoreline. The observed most important component of sea level anomaly at this tropical “storm free” coast is the influence from inverse barometer. Decadal observations from satellite show that sea level anomaly is continuously rising in the Gulf of Guinea subregion with expected strong consequence for this urbanized low lying sandy coast. © 2018 Springer Science+Business Media B.V., part of Springer Nature