Optical remote sensing has improved monitoring of aquatic systems by enabling remote or automated in situ characterization of biogeochemical parameters. Algorithms have primarily been based on empirical relationships---generally corresponding to oceanic (i.e., case-1) waters or else tuned to specific regions---derived using visible (VIS) wavelengths. Recent technological and algorithmic advances have revealed that aquatic remote sensing algorithms that use nonvisible wavelengths, including ultraviolet (UV) and near infrared (NIR), confer greater robustness to optical complexity, a concept termed End-Member Analysis (EMA). Longer wavelengths outside the NIR, i.e., shortwave infrared (SWIR), have not yet been evaluated for EMA due to high attenuation by water, and legacy observations of SWIR water-leaving signals often do not exceed noise. This presentation leverages recent technological advances to evaluate high signal-to-noise ratio SWIR water-leaving radiance observations that are compliant with an absolute radiometry perspective, i.e., individual waveband observations are absolute and do not require spectral normalization. Langley calibration results are shown for evaluation of radiometric performance, and SWIR water-leaving radiances from aquatic environments including the Southern Ocean, plus coastal and inland waters of California and Nevada (USA), are compared. Finally, the applicability of a SWIR black-pixel assumption for atmospheric correction is considered, along with potential future applications of SWIR radiometry for aquatic monitoring.

Primary Presenter: Henry Houskeeper, Woods Hole Oceanographic Institution (henry.houskeeper@whoi.edu)

Authors:

Henry Houskeeper, Woods Hole Oceanographic Institution  (henry.houskeeper@whoi.edu)

Stanford Hooker, National Aeronautics and Space Administration  (stanford.b.hooker@nasa.gov)

Tom Bell, Woods Hole Oceanographic Institution  (tbell@whoi.edu)