ABSTRACTS

Oral Session 4 | Tuesday, October 4, 14:40–15:00 | Abstract 689

Deployment of the Hyper-bb Spectral Backscattering Instrument in an Underway Flow-through System

Measurements of in-water absorption and backscattering with coincident in situ and satellite-measured radiometry are keys to refining and calibrating ocean color algorithms, as well as development of next generation (e.g., NASA PACE) hyperspectral ocean color products such as phytoplankton functional type. 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 recently developed and commercialized a new submersible hyperspectral backscattering sensor using a broadband white LED source, linear variable filters (LVF) as bandpass elements in transmit and receive optics, and a sensitive photomultiplier detector. Total spectral range covered is approximately 430-700 nm, limited by the LED at the low end and the LVFs at the upper end. The LVFs for transmit and receive sections are mounted on the same translation stage to move together to select only elastic scattering. The instrument projects a beam into the water at an angle and measures backwards scattered light with a limited field-of-view detector, providing the average volume scattering weighted over some angle range which can be empirically related to the backscattering coefficient. Plaque reflectance measurements as a function of distance are used to calibrate the instrument response. Here, we present details of the instrument, results of characterization and calibration studies, and data from the instrument deployed continuously for nearly a month in a specially designed flow-through chamber during the NASA EXPORTS 2021 cruise.

Thomas Leeuw, Sequoia Scientific, Inc.

Wayne Homer Slade, Sequoia Scientific, Inc., 0000-0003-1851-968X

David Dana, Sequoia Scientific, Inc.

Emmanuel Boss, University of Maine, 0000-0002-8334-9595