VIIRS Total Suspended Matter (TSM) for Chesapeake Bay

Satellite-derived total suspended matter (TSM) is a measure of the concentration of particulate material in the surface water such as mud, silt, and other fine-scale debris, including both organic and inorganic fractions.

The algorithm relates in-water sediment concentration measurements to the amount of light leaving the water -- the light that is eventually seen by the satellite. Red visible light is a good indicator of in-water sediment. In this case, the high-resolution red imaging band (638 nm) on the Visible Infrared Imaging Radiometer Suite (VIIRS) on-board the polar-orbiting Suomi-NPP satellite is used to calculate TSM.

In-water measurements of suspended sediment were taken over several seasons in Chesapeake Bay from 2017-2019 and related to the normalized water-leaving radiance of the VIIRS 638 nm imaging band, simulated from hyperspectral in-water radiance measurements. The in-water hyperspectral radiance measurements were taken simultaneously with the in-water suspended sediment measurements. The algorithm derivation is the same as that for MODIS TSM, as described in Ondrusek et al. (2012), but modified for the in-water hyperspectrally simulated VIIRS 638 nm imaging band.

Because the VIIRS red visible imaging band is a high-resolution band at 375 m spatial resolution, the TSM product provides very high spatial detail, which is useful for monitoring sediment distribution patterns in Chesapeake Bay tributaries, as well as the Bay's main stem.

TSM is a concentration measurement, so units are in mg/L.

NOAA CoastWatch East Code Node provides mapped satellite daily products of TSM, composited from all overpasses of the Suomi-NPP satellite over Chesapeake Bay in a single day (daytime overpasses only).

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