Long-Term Sea Surface Variability Regarding Seafloor Topography

Area of Science:

• Oceanography
• Geophysics
• Remote Sensing

Background:

• Regional sea level variability is influenced by complex interactions between ocean dynamics and seafloor topography.
• Understanding these influences is crucial for accurate sea level change predictions and coastal management.

Purpose of the Study:

• To analyze regional sea level variability across different seafloor structures, specifically ocean trenches/canyons and seamounts/corrugations.
• To compare sea level change trends over a 29-year period in these distinct geomorphological regions.
• To investigate the relationship between seafloor topography and sea surface variability.

Main Methods:

• Utilized hybrid datasets including satellite altimetric time series and multibeam bathymetric soundings.
• Incorporated GEBCO products, free-air gravity anomaly models, and mean dynamic ocean topography models.
• Employed radar remote sensing and spaceborne radar technologies to capture sea surface dynamics relative to seafloor topography.

Main Results:

• Regional sea level change trends were substantially higher in seamount/corrugation regions (2.56–7.66 mm/year) compared to trench/canyon regions (1.75–3.65 mm/year).
• Sea level trends in trench/canyon areas were stable and regular, while seamount/corrugation areas exhibited higher and irregular trends.
• Fluctuations in regional sea level were found to correlate with the complexity and diversity of seafloor structures.

Conclusions:

• Seafloor topography is a significant driver of regional sea level fluctuations.
• Complex bathymetry, such as that found in seamount and corrugation regions, leads to greater sea level variability.
• Despite susceptibility to climatic phenomena, trench and canyon regions show less sea level change amplitude than more complex areas.