HydroScat Backscattering Sensor Family

This HydroScat-2 profile clearly shows the advantages of the HydroScat Family's simultaneous backscattering (shown in red and blue) and fluorescence (shown in black) measurements.

The HydroScat-2 shows that chlorophyll concentrations are high near the surface, tapering down to zero at about 50 meters depth.  Scattering is also high in the surface layer, tracking the decrease in chlorophyll at increasing depth. However the scattering increases to a second peak at 130 meters. This peak is equal in magnitude to that near the surface, but note the differences: a greater separation between the red and blue backscattering traces, and no fluorescence. Thus the character of the particles in these two layers is distinctly different.

This plot shows both the down- and up-cast. Note that there is another peak in scattering at about 105 meters, which appears only on the downcast. One might be tempted to attribute this to a momentary contamination problem on the HydroScat, but simultaneous measurements with other instruments show these differences are genuine.  For more discussion of this comparison, please see our HydroProfiler Data Samples.