Vol. 36, issue 03, article # 11

Abstract:

Methods for measuring the salinity of seawater are considered. The results of an experimental study of samples of common and sea salt solutions with different salinity, poured into a hollow trihedral optical glass prism are presented. To measure the angles of refraction of light, a goniometric system was used, the minimum deviation method was implemented, which has a high accuracy of determining the refractive index. With dispersion analysis of experimental results, it is proved that the refractive index of water does not depend on its salt composition. An equation is suggested which describes the dependence of the refractive index on salinity and temperature for a fixed wavelength.
 

Keywords:

salinity scale, seawater salinity, salinity measurement, refractive index, refractometry, prism method, goniometric system

References:

1. Fizicheskaya geografiya materikov i okeanov / pod obshch. red. A.M. Ryabchikova. M.: Vyssh. shkola, 1988. 592 p.
2. Lyman J., Fleming R. Composition of seawater // J. Mar. Res. 1940. N 2. P. 134–146.
3. Forch C., Knudsen M., Sorensen S.P. Berichte uber konstantenbestimmungen zur Aufstellung der hydrographischen Tabellen. D. Kgl. Danske Vidensk., Selsk., Skrifter, 6 Raekke Naturvidensk. OgMath. 1902. Afd. 12, H. 1. P. 1–151.
4. RD 52.10.243-92 Rukovodstvo po himicheskomu analizu morskih vod. Spb.: Gidrometeoizdat, 1993. 265 p.
5. Cox R.A., Culkin F., Riley J.P. The electrical conductivity // Deep-Sea Res. 1970. V. 4, N 17. P. 679–689.
6. Millero F.J., Feistel R., Wright D.G., McDougall T.J. The composition of Standard Seawater and the definition of the Reference-Composition Salinity Scale // Deep-Sea Res. 2008. Iss. 55. P. 50–72.
7. International oceanographic tables. Paris. Nat. Inst. Oceanogr. // Great Britain and UNESCO. 1966. 128 p.
8. The practical salinity scale 1978 and international equation of State Seawater 1980. UNESCO tech. pap. mar. sci. 1981. P. 36–25. URL: https://salinometry. com/pss-78/ (last access: 3.09.2022).
9. Zaburdaev V.I. Nepostoyanstvo solevogo sostava morskoi vody i dostovernost' kosvennyh izmerenii solenosti, plotnosti po elektricheskoi provodimosti, temperature i davleniyu // Mor. gidrofiz. zhurn. 1985. N 4. P. 50–56.
10. Thermodynamic equation of Seawater-2010 TEOS-10. Canada, 2022. URL: http://www.TEOS-10.org (last access: 20.09.2022).
11. McDougall T.J., Jacket D.R., Millero F.J. A global algorithm for estimating Absolute Salinity // Ocean Sci. 2012. N 8. P. 1123–1134.
12. Ioffe B.V. Refraktometricheskie metody himii. L.: Himiya, 1974. 343 p.
13. Refraktometricheskie metody v fiziko-himicheskih izmereniyah / pod red. L.A. Konopel'ko. M.: Triumf, 2020. 208 p.
14. Yurin A.I., Vishnyakov G.N., Minaev V.L. Izmerenie pokazatelya prelomleniya s pomoshch'yu modifitsirovannogo metoda postoyannogo otkloneniya // Izmeritel'naya tekhnika. 2022. N 12. P. 35–39.
15. Le Menn M., Grosso P., Delauney L., Podeur C., Brault P., Guillerme O. Advances in measuring ocean salinity with an optical sensor // Meas. Sci. Technol. 2011. V. 22. P. 115202.
16. Chen J., Guo W., Xia M., Li W., Yang K. In situ measurement of seawater salinity with an optical refractometer based on total internal reflection method // Opt. Express. 2018. N 26. P. 25510–25523.
17. Born M., Vol'f E. Osnovy optiki. M.: Nauka, 1973. 97 p.
18. Millero F., Poisson A. International one-atmosphere equation of state of seawater. Deep-Sea Res. A. 1981. V. 28, N 6. P. 625–629.
19. Gritsenko I.V., Kovalev M.S., Stsepuro N.G., Guli­na Yu.S., Krasin G.K., Gonchukov S.A., Kudryashov S.I. The optical refractometry using transport-of-intensity equation // Laser Phys. Lett. 2022. V. 19. P. 076201.
20. Vishnyakov G.N., Levin G.G., Kornysheva S.V. Gosudarstvennyi pervichnyi etalon edinitsy pokazatelya prelomleniya // Izmeritel'naya tekhnika. 2004. N 11. P. 3–6.
21. Pavlov P.A., Filatov Yu.V., Zhuravleva I.B. Calibration of rotary encoders with different interfaces by means of a dynamic goniometer // Opt. Eng. 2021. V. 60, N 7. P. 074105.
22. Tilton L.W. Prism Refractometry and Certain Goniometrical Requirements for Precision National Bureau of Standards, Gaithersairg, 1929.
23. ISO 21395-1:2020 Optics and photonics – Test method for refractive index of optical glasses — Part 1: Minimum deviation method. International Organization for Standardization, 2020.
24. Inertekh. SPb., 2022. URL: http:// inertech-ltd.com/ (data obrashcheniya: 20.09.2022).
25. Dzhonson N., Lion F. Statistika i planirovanie eksperimenta v tekhnike i nauke. Metody obrabotki dannyh. В 2-х т. M.: Mir, 1980. 274 p.
26. Quan X., Fry E.S. Empirical equation for the index of refraction of seawater // Appl. Opt. 1995. V. 34, N 18. P. 3477–3480.
27. Austin R.W., Halikas G. The Index of Refraction of Seawater. SIO Ref. N 76-1. La Jolla, California: Scripps Institution of Oceanography, 1976. Р. А4–А21.