Global 3-D Electrical Conductivity Model of the World Ocean and Marine Sediments

This study presents global 3-D electrical conductivity models of the world ocean and marine sediments. Electrical conductivity of the ocean was calculated by invoking the Equation of State of Seawater (TEOS-10) with temperature and salinity data retrieved from the World Ocean Atlas and a series of high-resolution regional ocean climatology data sets. The resolution of the ocean conductivity atlas varies between 0.1 degrees and 0.25 degrees globally. The conductivity of marine sediments was estimated by using compaction and thermal gradient models constrained by real observations on a 5-arc-minute global marine sediment thickness grid. I present numerical simulations of electromagnetic (EM) induction responses that demonstrate a significant effect of 3-D electrical conductivity of the ocean and marine sediments on EM responses for a broad range of frequencies. I show that both marine and land-based surveys designed for subsurface conductivity imaging or Space Weather modeling will benefit from inclusion of more realistic conductivity models of the ocean and seabed sediments.