AbstractA prototype point-source integrating-cavity absorption meter is presented and compared to spectrophotometric absorption
measurements. Different light collector assemblies of the PSICAM
were tested regarding their capability to determine the absorption of
water constituents accurately over a wide range of concentrations and
scattering properties. The PSICAM setup with a radiance-type sensor showed the best performance. It was
compared with a photometric absorption determination using
non-scattering dye solutions. The mean difference between both methods was less than 2.4 \% in the spectral range of 400 to 700 nm.
The absorption determination with the PSICAM, when equipped with a radiance sensor as a light collector, was only little affected by scattering and temperature.
We conclude that the PSICAM can be used operational for determining
the absorption of natural sea water samples at ambient temperatures.