Direct temperature and salinity acoustic full waveform inversion

Recent work has shown that Full Waveform Inversion could be suitable to extract physical properties such as sound speed ( c ), density ( ρ ), temperature ( T ), and salinity ( S ) from the weak impedance contrasts associated with the ocean's thermohaline fine structure.The seismic inversion approaches proposed so far are based on the iterative inversion of c from multichannel seismic data, while the rest of parameters ( T , S , and ρ ) are determined in a second step using two equations of state and a local T ‐ S empirical relationship. In this work, we present an alternative to this approach. Using 1‐D synthetic seismic data, we demonstrate that the direct full waveform inversion of T and S using adjoint methods is feasible without the use of any local T ‐ S relationship and that the models of physical properties obtained with this approach are far more accurate than those inferred from c .