Experimental remote sensing of subsurface temperature in natural ocean water

Abstract

A remote sensing laser Raman backscattering technique has made the first field measurements, from a boat, of subsurface temperature in natural ocean waters. These results and the measurement systems rapidly developing from them open wide areas of exploitation. The technique utilizes the observation of the 3400 cm−1 O‐H stretching Raman band of liquid water. The spectral data were analyzed to obtain the subsurface water temperature in accordance with previous laboratory studies. The importance of such a measurement by the Raman scattering technique is that it now enables depth resolved profiles of ocean water temperature to be obtained by remote sensing from airborne platforms that can be adapted for application to many problem areas of physical oceanography, meteorology, climatology, ocean technology, and thermal discharge management. An accuracy of ± 2°C has been obtained in the initial field experiments. A more refined system has been designed which will permit accuracies of better than ± 1°C in the first one or two optical attenuation lengths of depth.