Vertical distribution of the sound speed and it`s mean value in depth measurements using a singlebeam echosounder

For hydrographic measurements is often used a single beam high precision echosounder. The depth is calculated by means of the mean value of the sound speed. In connection with local substitutions of original parameters of water, mainly temperature, in the measured area the sound speed and its mean value are not constant. In case of high change of the sound speed, the depth measurements have big error. It is very important in lowdepth. In areas with high change of the sound speed yhere is possible to determine three-dimensional distributions of the sound speed and using local distribution in 6the measuting point of the depth.