METHOD FOR CALCULATING THE SEAWATER SOUND VELOCITY TO MEASURE RAPIDLY CHANGING OCEAN PROCESSES

Abstract

The paper presents two compact polynomial equations expressing the dependence of the sound speed of sea water on the input parameters: in situ temperature, hydrostatic pressure and absolute salinity. The equations are obtained by approximating the standard International Thermodynamic Equation of Seawater-2010 (TEOS-10). The first equation is intended to be used for the technical purposes and reproduces the TEOS-10 data on the seawater sound speed over the wide range water environment parameters with a standard deviation of 0.987 cm/s. The second, more accurate equation is for the scientific use and reproduces the TEOS-10 data on the seawater sound speed over the oceanographic range water environment parameters with a standard deviation of 0.113 cm/s. The equations can be used to solve direct and inverse computational problems. In the direct computational problem, the sound speed value is calculated from the three input parameters measured values. In the inverse computational problem, the value of an unknown input parameter is determined from the measured values of the sound speed and two other input parameters. As a result of the experiments, the higher efficiency of the developed equations was confirmed in terms of their speed, saving energy and computer memory in comparison with the use of the International Equation TEOS-10. The developed equations, algorithms and programs for microcontrollers are convenient tools to equip various offshore platforms and especially fastmoving submersibles. The application of these equations makes it possible to obtain experimental data with high accuracy, to carry out measurements in real time in a rapidly changing aquatic environment, which can also be used to correct the movement of the submersibles.