A Discrepancy between Calculation and Measurement of Submarine Illumination.

SCRIPPS INSTITUTION OF OCEANOGRAPHY,* UNIVERSITY OF CALIFORNIA, LA JOLLA, CALIFORNIA Communicated by Carl L. Hubbs, August 5, 1955 An investigation of the behavior of the sonic-scattering layer in the region of the San Diego Trough has proved that it is closely associated with the degree of submarine illumination.' This finding could not have been predicted by extrapolating from light measurements made in surface layers in this area. Such measurements were made by Richardson2 with a sodium-vacuum phototube at midday in August, 1930 (Fig. 1, broken line). Extrapolation from these data would yield values of light intensity indicated by the open circles in Figure 1.