Regional Seafloor Topography by Extended Kalman Filtering of Marine Gravity Data without Ship-Track Information

Lucía Seoane,Corinne Salaün,José Darrozes,Guillaume Ramillien,Thierry Schmitt,Didier Rouxel,Frédéric Frappart,Benjamin Beirens

doi:10.3390/rs14010169

Abstract

An iterative Extended Kalman Filter (EKF) approach is proposed to recover a regional set of topographic heights composing an undersea volcanic mount by the successive combination of large numbers of gravity measurements at sea surface using altimetry satellite-derived grids and taking the error uncertainties into account. The integration of the non-linear Newtonian operators versus the radial and angular distances (and its first derivatives) enables the estimation process to accelerate and requires only few iterations, instead of summing Legendre polynomial series or using noise-degraded 2D-FFT decomposition. To show the effectiveness of the EKF approach, we apply it to the real case of the bathymetry around the Great Meteor seamount in the Atlantic Ocean by combining only geoid height/free-air anomaly datasets and using ship-track soundings as reference for validation. Topography of the Great Meteor seamounts structures are well-reconstructed, especially when regional compensation is considered. Best solution gives a RMS equal to 400 m with respect to the single beam depth observations and it is comparable to RMS obtained for ETOPO1 of about 365 m. Larger discrepancies are located in the seamount flanks due to missing high-resolution information for gradients. This approach can improve the knowledge of seafloor topography in regions where few echo-sounder measurements are available.

Highlights

Accurate knowledge of the Earth’s topography remains fundamental to understand surface processes
Detailed mapping of the sea floor topography is essential for studies in oceanography, biology, marine geology, natural disasters, airline crashes over ocean [1] habitat loss and marine resources
We checked the contribution of a combined-data of different of different observations, geoid heights and free-air anomalies, in inversion order to improve the observations, geoid heights and free-air anomalies, in order to improve the seafloor toseafloor topography assessment

Summary

Introduction

Accurate knowledge of the Earth’s topography remains fundamental to understand surface processes. Detailed mapping of the sea floor topography (or bathymetry) is essential for studies in oceanography, biology, marine geology, natural disasters, airline crashes over ocean [1] habitat loss and marine resources. Currents and tides physical characteristics are controlled by the shape of the seafloor as well as smaller-scale topographic features like seamounts. Our knowledge of seafloor topography remains imprecise. The traditional technique to map bathymetry is a tedious process made by research vessels equipped with single or multibeam echo-sounders [2,3]. Using this traditional technique only less than

Methods

Results

Conclusion