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The Visible/Infrared Imaging Radiometer Suite (VIIRS) is the NOAA operational follow-on to the Moderate Resolution Imaging Spectrometer on NASA’s Earth Observing System. VIIRS operates on the Joint Polar-orbiting Satellite System which is the now current NOAA low-earth orbit operational Meteorological Satellite system. The VIIRS has Moderate (750 m nadir resolution) and Imaging (375 m nadir resolution) bands, as well as a band with large dynamic range that operates as a 750 m resolution, full swath imaging band in both day and night viewing conditions. This presentation will look at one specific M-band centered at 680 nm and one I-band centered at 640 nm which are nested spectrally, but for which the I-band has an 80 nm bandwidth and the M-band has a 20 nm bandwidth. We will show that an additional band of 60 nm (centered at 630 nm) may be synthesized from these two bands because the trailing edges of the spectral response of these two bands are nearly identical. The synthetic band will have lower radiometric accuracy and is considered most useful for diagnostic rather than specific quantitative objectives. Potential guidelines for the use of this synthetic band are provided also. A coarse uncertainty budget is shown that provides the uncertainty sources unique to the synthetic band, which are in addition to the uncertainties of the input bands. The concept of constructing a synthetic spectral band in this manner is considered an appropriate remote sensing concept only in the context of spectro-radiometric calibration approaches when tunable laser-source, absolute detector based calibrations are provided due to the enhanced calibrations with this class of standard devices. Traditional radiometric calibrations using integrating spheres are not considered sufficiently precise or sufficiently accurate to support computations of this nature.
This may be thought of as a solution looking for a problem. Then we will show the results of an investigation into applying this solution to the detection of Harmful Algal Blooms (HAB). Laboratory results from the literature are introduced showing that species common to HAB in the Florida USA Gulf Coast have an absorption feature centered near 630 nm. This species is Karenia brevis which is the most common algae in West Florida shelf HABs. HAB outbreaks observed within the 6-year VIIRS dataset will be investigated using this synthesized band to assess the usefulness of this band as another tool for the study of coastal processes.
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