WRRCTR No.18 Remote Sensing of Hawaiian Coastal Springs Using Multispectral and Infrared Techniques

Abstract

Two remote sensing techniques of measuring offshore ground-water spring discharge that have been studied are: (i) multispectral photography, and (ii) infrared thermometry. During the summer of 1967, exposure factors for filter-film-camera combinations extending outside the visible spectra were experimentally determined and tabulated. One spectral series of simulated aerial photography was obtained. Darkroom procedures and equipment for multispectral enhancement of the suspected color differences between sea water and offshore spring water in these photographs have not yet been precisely defined. Helicopter flights with an infrared thermometer have demonstrated that offshore springs can be identified by their temperatures. Due to the irregular shape, size, and location of these fresh water outflows, a synoptic technique is needed. An infrared scanner is desirable but the present costs are prohibitive.