Sea Level Variability Assessment along the African Coast

Abstract

Studying changes in the sea level is essential for the sustainable development of coastal areas. The aim of this study was to analyse time series and investigate the regional variability of the sea surface and the effect of individual factors on its behaviour. In this study, we utilised the most recent satellite altimetry data (over a period of 29 years, i.e., from 1993 to 2022) and tide gauge observations (long-term time series) in order to estimate changes in the sea level. Unlike in previous studies, the rates of the sea level changes around the entire African coast were determined. In addition, time series of the changes in the sea surface temperature and salinity were used to determine the rate of changes arising from the thermal expansion of the ocean. The regional rate of the sea level rise between 1993 and 2022 deviated significantly from the global average, with values ranging from 2.48 to 5.44 mm/year (based on satellite altimetry data, depending on the location of the point).