How is VIIRS EDR Imagery Validated?

VIIRS Imagery from the Suomi-NPP satellite is the highest spatial resolution (375 m) multi-spectral imagery of any operational satellite to date. The polar-orbit and wide/overlapping swaths allow global coverage of the entire world every 12 hours. During the post-launch phase, the emphasis was on characterizing the performance of VIIRS EDR Imagery (derived from real on-orbit instrument data) as well as identifying and making necessary product algorithm refinements. The Imagery EDRs share calibration/validation activities with the VIIRS SDR Cal/Val Team, where most of the VIIRS calibration activity occurs. However, the Imagery EDR is a Key Performance Parameter for VIIRS, whose quality is vital to the success of the JPSS satellites carrying this instrument. Because VIIRS covers the high-latitude and polar regions especially well, with both high spatial resolution and acceptable temporal coverage, the Alaska theatre in particular benefits from VIIRS more that lower-latitude regions where geostationary imagery provides better temporal coverage.

While there are no requirements that specifically address the quality of the EDR Imagery aside from the VIIRS SDR requirements, there is a critical aspect to VIIRS Imagery which makes it an important consideration in the Cal/Val process. Ultimately, it is the end users who decide whether the quality of the Imagery is acceptable, and as such including the users in the Cal/Val process for Imagery is a key consideration in the Imagery validation strategy.

Although VIIRS high-resolution visible and infrared capabilities are clear, user validation is also tied to the unique features of VIIRS, including the Day/Night Band (DNB) that is not available from any current or near-future geostationary platform. The DNB, and the NCC derived from it, have found widespread use across NOAA and the NWS. NCC is capable of providing visual images at night, even under no moon conditions. While the quality varies with the amount of moonlight, day-night imager has proven useful in locating clouds, ice edges, snow cover, tropical cyclone centers (eyes), fires and gas flares, lightning, dust storms, and volcanic eruptions.

VIIRS Imagery is being incorporated into operational analysis and forecasting via distribution through the AWIPS to NWS users. VIIRS Imagery of significant weather and weather-related features is also made available on numerous blog and social media venues, where most of its non-meteorological users reside. For either type of user the best image quality is important, since users are a vital component to the validation of VIIRS Imagery.