The Index of Refraction of Seawater

SIO Reference 76-1. ft smoothly varying and internally self-consistent set of tables of the index of refraction of seawater with respect to air are presented. The dependence of the index on salinity (0 to 43°/00), temperature (0 to 30°C), wavelength(400 to 700 nm) and pressure (0 to 1100 kg/cm2 gage) has been fully covered. The relevant literature from prior to 1900 through the present has been extensively reviewed. Various comparisons between indices obtained from these sources and the tables presented have been performed suggesting an overall accuracy of the tabulated index values of about 3 x 10~s at atmospheric pressure and 1 x 10~4 at higher pressures. The extreme values encountered were 1.32921 and 1.36844, while the average slopes of the index surface, over the range of the variables considered, are An/As « 0.009/43°/00, An /At« - 0.002/30°C, An/AA« -0.013/300 nm, An/Ap« 0.015/1100 kg/cm2. Three dimensional diagrams provide complete views of the index of refraction surface.The requirements necessary for obtaining salinity and specific gravity directly from measurements of the index of refraction, for oceanographic purposes have been examined.