This paper describes a submersible spectroradiometer for measuring the spectral distribution of the multiply scattered natural light in ocean or lake water. Because of the anticipated large range of flux levels in the spectrum at the exit slit, strong measures have been taken to reduce stray light within the instrument. These methods are described in some detail. Procedures for spectral alignment and calibration, determination of bandwidth, absolute calibration, and over-all testing of the instrument are described in detail and the probable errors introduced by various components are estimated. It is estimated that the precision of measurements, limited by random errors of data taking, will be within ±2.5% and that the absolute accuracy is between 5% and 12%. The major limitations on the accuracy are the uncertainties of the standard of spectral emittance and the measurement of the bandwidth of the instrument.
The instrument makes possible a mode II determination of the optical properties of natural water as a function of wavelength and can furnish data on the spectral distribution of the flux available for photosynthesis and animal stimulation.
© 1966 Optical Society of AmericaFull Article | PDF Article