Relationship of Satellite Altimetry Data, and Bathymetry Observations on the West Coast of Africa

Abstract

The sea surface is variable in time and space; therefore, many researchers are currently interested in searching for dependencies and connections with the elements influencing this diversity, e.g., with the seabed topography. An important problem is combining or comparing models obtained based on different data sets with different accuracies and spatial resolutions. These studies are designed to discover the relationship that may exist between observations of the shape of the seabed and changes in sea level. The aim of this study is to investigate the relationship by checking the correlation between the observations from the point recording of satellite altimetry measurements and the bathymetric data. The object of research is the capital city of Gabon—Libreville, located on the west coast of Africa and three point in Las Palmas. The results present sea level, salinity, and potential temperature variations in selected points. The highest trends of sea level changes occur, at one point, in the open ocean (P6) and at coastal points (Libreville, P3, Pointe Noire). The study indicates that, from 1993 to 2020, the temperature trend at the assessed points is on average 0.018 ± 0.012 °C·year−1, while the average salinity trend is 0.008 ± 0.005 1e−3 year−1. The correlation coefficients for the sea water temperature trend and the sea water salinity trend—determined at 0.20 and 0.08—present a weak linear relationship. Correlation takes slightly higher values for elevation, which is determined at 0.38. Research shows that there is a relationship between satellite and bathymetric observations on the east coast of Africa; however, the strength of the correlation depends on the location.

Keywords

• sea level changes
• seafloor topography
• satellite altimetry
• bathymetry
• GEBCO
• CMEMS