Investigating an Instrument for Measurement of Hyperspectral Backscattering in Natural Waters

The remote sensing reflectance signal measured by an ocean color satellite is to first order proportional to the ratio of backscattered to absorbed light. Therefore in situ measurements of absorption and backscattering, as functions of wavelength, along with in situ and satellite radiometery, are key to refinement and calibration of legacy ocean color algorithms, as well as development of next generation ocean color products such as phytoplankton functional type. Currently, commercial instruments exist for in situ measurement of the hyperspectral absorption coefficient, but no instrument exists for measurement of the hyperspectral backscattering coefficient. We propose to develop an active sensor for in situ measurement of the hyperspectral backscattering coefficient. The proposed instrument will use a broadband halogen lamp source, servo-controlled linear variable filters as spectral bandpass elements in transmit and receive optics, and a photomultiplier tube detector with integrated low-noise amplifier and variable gain. The proposed instrument addresses a critical gap in the field of currently available systems for measuring hyperspectral IOPs in situ, in support of hyperspectral ocean color missions.