Document Type

Article

Publication Date

4-2022

DOI

10.1002/lno.12088

Publication Title

Limnology and Oceanography

Volume

67

Issue

6

Pages

1374-1387

Abstract

Oceanographic lidar measurements of the linear depolarization ratio, δ, contain information on the bulk characteristics of marine particles that could improve our ability to study ocean biogeochemistry. However, a scarcity of information on the polarized light-scattering properties of marine particles and the lack of a framework for separating single and multiple scattering effects on δ have hindered the development of polarization-based retrievals of bulk particle properties. To address these knowledge gaps, we made single scattering measurements of δ for several compositionally and morphologically distinct marine particle assemblages. We then used a bio-optical model to explore the influence of multiple scattering and particle characteristics on lidar measurements of δ made during an expedition to sample a mesoscale coccolithophore bloom. Laboratory measurements of linear depolarization revealed a complex dependency on particle shape, size, and composition that were consistent with scattering simulations for idealized nonspherical particles. Model results suggested that the variability in δ measured during the field expedition was driven predominantly by shifts in particle concentration rather than their bulk characteristics. However, model estimates of δ improved when calcite particles were represented by a distinct particle class, highlighting the influence of bulk particle properties on δ. To advance polarized lidar retrievals of bulk particle properties and to constrain the uncertainty in satellite lidar retrievals of particulate backscattering, these results point to the need for future efforts to characterize the variability of particulate depolarization in the ocean and to quantify the sensitivity of operational ocean lidar systems to multiple scattering.

Data Availability

Article states: "The data that support the findings of this study are available from the corresponding author upon reasonable request."

Corresponding author: Brian L. Collister, Old Dominion University (bcoll018@odu.edu)

Comments

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

© 2022 The Authors.

Original Publication Citation

Collister, B. L., Zimmerman, R. C., Sukenik, C. I., Balch, W. M., & Hill, V. J. (2022). The influence of particle concentration and bulk characteristics on polarized oceanographic lidar measurements. Limnology and Oceanography, 67(6),1374-1387. https://doi.org/10.1002/lno.12088

ORCID

0000-0003-0385-0337 (Collister), 0000-0002-9399-4264 (Zimmerman), 0000-0001-5025-2546 (Sukenik), 0000-0001-8337-7441 (Hill)

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