New Hyperspectral Absorption and Backscattering Instruments for Ocean Color and Biogeochemistry

Measurements of in-water absorption and backscattering with coincident in situ and satellite-measured radiometry are keys to refining and calibrating ocean color algorithms and developing next generation (e.g., NASA PACE) hyperspectral ocean color products such as phytoplankton community composition. Beyond ocean color applications, these in situ instruments also offer the capability to measure particle and dissolved material properties directly applicable to ocean biogeochemistry research. Currently, commercial instruments exist for in situ measurement of hyperspectral radiometry and absorption coefficient, while measuring backscattering with a single instrument has been limited to multispectral. We have developed and commercialized a new submersible single-angle hyperspectral backscattering sensor using a white LED source, linear variable bandpass, and a sensitive photomultiplier detector. More recently, we have also developed a new hyperspectral absorption sensor using an integrating cavity to reduce measurement uncertainty due to scattering errors inherent in the reflective tube design. This new design also employs a solid standard for routine field calibration to avoid uncertainties and difficulties associated with field calibration using nigrosine solution standards. We will present details of the backscattering and absorption instruments, challenges underlaying hyperspectral IOP instrument design, results of characterization and calibration studies, and field data including an examination of closure between inherent optical properties (IOPs) and radiometry.

Primary Presenter: Kirby Simon, Sequoia Scientific, Inc. (kirby.simon@sequoiasci.com)

Authors:

Kirby Simon, Sequoia Scientific, Inc.  (kirby.simon@sequoiasci.com)

Wayne Slade, OceanSense, LLC  (wslade@oceansense.us)

Thomas Leeuw, Sequoia Scientific, Inc.  (tleeuw@sequoiasci.com)

David Dana, Sequoia Scientific, Inc.  (ddana@sequoiasci.com)

Michael Twardowski, Harbor Branch Oceanographic Institute  (mtwardo.alt@gmail.com)

Alberto Tonizzo, Sunstone Scientific LLC  (alberto.tonizzo@gmail.com)

Chrisopher Strait, Harbor Branch Oceanographic Institute  (cstrait2017@fau.edu)