Analyzing harbor water and earth temperatures

IN THE ENGINEERING studies of a possible installation of submarine cables at some depth below the Baltimore Harbor, data were required on thermal diffusivity and variations of ambient earth temperatures at various depths throughout the year. From measurements over a 20-year period, certain facts about the general character of the temperature variation of the water at the bottom of the Baltimore Harbor are known: (1) The average annual water temperature at the bottom of the harbor, is within a few degrees of the average annual air temperature in Baltimore. (2) The water temperature closely follows in magnitude, but lags behind the mean daily air temperature.