Instruments and methods for measuring the backward-scattering coefficient of ocean waters

Area of Science:

• Ocean optics and remote sensing
• In-situ optical measurements
• Particulate matter characterization

Background:

• The backward-scattering coefficient (bb) is a key optical property influencing ocean color, water clarity, and visibility.
• Accurate measurement of bb is vital for understanding marine environments and suspended particle dynamics.

Purpose of the Study:

• To investigate the fixed-angle backscattering sensor approach for measuring bb.
• To develop a procedure for determining the sensor-response function for accurate bb estimation.
• To identify optimal sensor-response angle ranges for improved bb measurement accuracy.

Main Methods:

• Analyzing sensor response as an integral of the volume scattering function (VSF) weighted by the sensor-response function.
• Developing a procedure to determine the sensor-response function for full sensor calibration.
• Evaluating the correlation between backscattering measurements and bb at different angles.

Main Results:

• Sensor response is directly related to the VSF integrated over backward angles.
• Optimal bb estimation is achieved when the sensor-response function covers the 110-160 degree range.
• Backscattering measurements near 90 and 180 degrees show the least correlation with bb.

Conclusions:

• Fixed-angle backscattering sensors can accurately measure bb with a well-defined sensor-response function.
• The middle range of backscattering angles (110-160 degrees) is most reliable for bb estimation.
• Developed spectral backscattering sensors and their response functions are presented.