Sound absorption in sea water by a third chemical relaxation

Evidence is presented for a third chemical relaxation producing sound absorption in the ocean. After accounting for sound absorption in the Atlantic and Pacific due to boric acid, magnesium sulfate, and water, there appears to be a third relaxation at 3 kHz (possibly higher) with $αλmax = 0.28 × 10−5$ at 4°. The existence of this relaxation was determined by using the Fisher—Simmons equation for sound absorption based on Simmons' laboratory work. For the Pacific data, the boric acid contribution was reduced to 0.4 that of the Atlantic. The third relaxation was deduced from Thorp's data in the Atlantic and Lovett's data in the Pacific. The new relaxation may be the one predicted by Garland, Patel, and Atkinson for $MgHCO3$ for which $αλmax = 0.58 × 10−6$ at 9 kHz at 25°. [Work supported by the Office of Naval Research.]