Deep Argo improves mapping of the seafloor

The knowledge of the shape and depth of the bottom of the ocean is critical to assess and predict plate tectonic movement, tsunami generation, tidal circulation, storm surge propagation and the evolution of habitats near the seafloor. Shipboard sounding surveys cover less than 25% of the ocean floor leaving 75% uncharted. In regions where echosounding data is not available, ocean bathymetry can be inferred from gravity using satellites. While satellite coverage is mostly global, gaps between satellite tracks, attenuation of the signal with depth and noise alter the accuracy of bathymetry measurements derived from satellites. Deep Argo floats are autonomous robotic platforms profiling temperature, salinity and pressure from the surface to 6000 m maximum depth every 10 days. Deep Argo floats are not equipped with an echosounder, but their pressure sensors provide reliable estimates of the ocean depth. About 66% of the Deep Argo profiles accumulated over the past decade have programmed maximum depth extending to the seafloor, enabling thousands of valuable bathymetric measurements to be derived. Our analysis shows great agreement between Deep Argo derived bathymetry estimates and multibeam echo sounding data over several regions of the Atlantic, Pacific, Indian and Southern oceans. These results demonstrate the capacity of Deep Argo floats to measure bathymetry with a high degree of accuracy. With Deep Argo profiles being transmitted at the end of each 10-day cycle via Iridium satellite communication systems, and then analyzed to determine detection of the seafloor, Deep Argo has the ability to rapidly improve our understanding of the bathymetry of the ocean floor in the deepest and most remote regions of the world ocean.