AUTHOR=Jamet Cédric , Ibrahim Amir , Ahmad Ziauddin , Angelini Federico , Babin Marcel , Behrenfeld Michael J. , Boss Emmanuel , Cairns Brian , Churnside James , Chowdhary Jacek , Davis Anthony B. , Dionisi Davide , Duforêt-Gaurier Lucile , Franz Bryan , Frouin Robert , Gao Meng , Gray Deric , Hasekamp Otto , He Xianqiang , Hostetler Chris , Kalashnikova Olga V. , Knobelspiesse Kirk , Lacour Léo , Loisel Hubert , Martins Vanderlei , Rehm Eric , Remer Lorraine , Sanhaj Idriss , Stamnes Knut , Stamnes Snorre , Victori Stéphane , Werdell Jeremy , Zhai Peng-Wang 

TITLE=Going Beyond Standard Ocean Color Observations: Lidar and Polarimetry

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 6 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2019.00251

DOI=10.3389/fmars.2019.00251

ISSN=2296-7745

ABSTRACT=Passive ocean color images have provided a sustained synoptic view of the distribution of ocean optical properties and color and biogeochemical parameters for the past twenty-plus years. These images have revolutionized our view of the ocean. Remote sensing of ocean color has relied on measurements of the radiance emerging at the top of the atmosphere, thus neglecting the polarization and the vertical components. Ocean color remote sensing utilizes the intensity and spectral variation of visible light scattered upward from beneath the ocean surface to derive concentrations of biogeochemical constituents and inherent optical properties within the ocean surface layer. However these measurements have some limitations. Specifically, the measured property is a only weighted-integrated values over from a relatively shallow depth, the measurements provide no information during the night and retrieval are compromised by clouds, absorbing aerosols and low Sun zenithal angles. In addition, ocaen color data provide limited information on the morphology and size distribution of  marine particles. Major advances in our understanding of global ocean ecosystems will require measurements from new technologies, specifically lidar and polarimetry. These new techniques have been widely used for atmospheric applications but have not had as much as interest from the ocean color community. This is due to many factors including limited access to in-situ instruments and/or space-borne sensors and lack of attention in university courses and ocean science summer schools curricula. However, lidar and polarimetry technology will provide an complement to standard ocean color products by providing depth-resolved values of attenuation and scattering parameters and additional  information about particles morphology and chemical composition. This review aims at presenting the basics of these techniques, examples of applications and at advocating for the development of in-situ and space-borne sensors. Recommendations are provided on actions that would foster the embrace of lidar and polarimetry as powerful remote sensing tools by the ocean science community.