Determination of sensor depth from downwelling irradiance measurements

The wave focusing effect causes measurements of under water downwelling irradiances E_d to be extremely variable in intensity and spectral shape. A new analytical model for E_d has been developed recently, which can deal with the induced variability by treating the direct and diffuse components of E_d separately. This paper presents a method to determine the current sensor depth from under water downwelling irradiance measurements using that model combined with improved parameterizations for the direct and diffuse downwelling attenuation coefficients. The average relative deviation of sensor depth for a data set containing over 1400 measurements under various illumination conditions and depths is on the order of 5 %.