En korreksjon til ekkoloddets dybdeangivelse

Abstract

An echo sounder is adjusted for constant sound velocity, usually 1500 m/sec. Since the velocity of sound in the sea is varying with temperature, salinity and depth, a correction is necessary if accurate soundings are required. The present paper shows a practical method for the computation of this correction. 49 of the "G. Sars" stations, taken in the years 1951-55, are fairly well covering the Norwegian Sea (Fig. 3). These stations have been used as basic material for the computation of the depth correction presented in Figs. 4-10. The correction is given as percentage of measured echo depth for the following depths (meters): 500, 1000, 1500, 2000, 2500, 3000, and 3500.