Recover of temperature, salinity and potential density from acoustic reflectivity in the ocean

Abstract

We present the inversion of temperature, salinity and potential density from time and space-coincident acoustic reflectivity and XBT data in the Gulf of Cadiz, NE Atlantic Ocean. This method recovers low frequency content (< 10 Hz) of the impedance from XBTs and the high frequency content (> 10 Hz) from acoustic reflectivity. Afterwards, maps of temperature and salinity are calculated from impedance using the GSW equations of state and an empirical T-S relation obtained with Neural Networks. This method allows to recover the main physical oceanographic parameters in the ocean with accuracies of δTsd = 0.1oC, δSsd = 0.09 and δρsd = 0.02kg/m3 for temperature, salinity and potential density respectively, along lateral sections of hundreds of km, covering all the full-depth water column and with vertical and lateral resolutions of 10 m and 100 m, respectively. Acoustic reflectors and inverted potential density are eventually compared to better understanding the contribution of the acoustic reflectivity to the physic observation of the ocean