The University of Maine Maine In-situ Sound & Color Lab
School of Marine Sciences
Is the Spectral Shape of Particle Backscattering a Good Indicator of Particle Size?

The particulate beam attenuation is a fundamental measure of the water turbidity, and a useful proxy for total particulate mass and organic carbon. Additionally, its functionality with wavelength is theoretically and empirically correlated with a simple descriptor of the bulk particulate size distribution. However, the spectral particulate beam attenuation cannot currently be measured from autonomous vehicles or over long periods on moored observing systems due to size limitations, bio-fouling, and power demand. Recently, sensors measuring spectral particulate backscattering have been deployed at moored observatories and on autonomous underwater vehicles, and some have suggested this measurement could be used to obtain information regarding the particulate size distribution. In this study, we investigate this possibility using collocated measurements of particulate attenuation and particulate backscattering spectra (WETLabs ac-9 and bb-9) collected one meter off the bottom in a shallow (12m) observing station. Preliminary examination shows a significant relationship between the spectral slope of particulate attenuation and specific spectral band ratios of particulate backscattering. This suggests that in some cases particulate size distribution information can be obtained from backscattering measurements.

Slade, W.H. and E. Boss, 2008. Is the Spectral Shape of Particle Backscattering a Good Indicator of Particle Size? 2008 Ocean Sciences Meeting, Orlando, FL, March 2-7.

  The University of Maine
Orono, Maine 04469
(207) 581-­1110
Website last updated: 18-Mar-14