Water States - Corrected Reflectance (VIIRS / NOAA-20)

Overview and Intended Use This visualization represents a "false color" band combination (Red = M3, Green = I3, Blue = M11) of data collected by the VIIRS instrument on NOAA’s Joint Polar Satellite System ([JPSS-1]) satellite, which was renamed to NOAA-20 once on orbit. The imagery is most useful for distinguishing water in its various states (e.g. liquid, ice, and snow). For example, clouds over snow, ice cloud versus water cloud; or floods from dense vegetation. At its highest resolution, this visualization represents the underlying data scaled to a resolution of 250m per pixel at the equator. The VIIRS Corrected Reflectance product retains visible aerosols for a natural-looking visualization, though gross atmospheric effects (e.g. Rayleigh scattering) have been removed. The following guidelines will aid in understanding this visualization. See [here] for additional information on how this "false color" band combination highlights these physical characteristics of the Earth. * Thick ice and snow appear a vivid red (or dark pink), while ice crystals in clouds will appear pinkish. * Vegetation will appear green. * Naturally bare soil, like a desert, will appear bright cyan. * Liquid water on the ground will appear very dark, while water droplets in clouds will appear white. * Sediments in water will appear dark red. Multi-Spectral Bands The following table lists the VIIRS bands that are utilized to create this visualization. See [here] for a full description of all VIIRS bands. ────┬────────────────────┬───────────────┬────────────── Band│Description │Wavelength (µm)│Resolution (m) ────┼────────────────────┼───────────────┼────────────── I3 │Shortwave IR (Red) │1.58 - 1.64 │375 │ │ │ ────┼────────────────────┼───────────────┼────────────── M3 │Visible (reflective)│0.478 - 0.488 │750 │ │ │ ────┼────────────────────┼───────────────┼────────────── M11 │Shortwave IR │2.23 - 2.28 │750 │ │ │ ────┴────────────────────┴───────────────┴────────────── Temporal Coverage and Limitations of Use By default, this layer will display the imagery currently available for today’s date. The update frequency of the imagery is a "daily composite" that is assembled from hundreds of individual data files. When viewing imagery for “today,” you may notice that only a portion of the map has imagery. This is because the visualization is continually updated as the satellite collects more data. To view imagery over time, you can update the layer properties to [enable time animation] and [configure time settings]. The current version of this layer is available from present back to April 25th, 2020. In the coming months, this will be extended to the start of the mission (November 18th, 2017). Source: NASA Global Imagery Browse Services (GIBS), NASA Worldview, & NASA LANCE This visualization is provided through the [NASA Global Imagery Browse Services (GIBS)], which are a set of standard services to deliver global, full-resolution satellite imagery for hundreds of NASA Earth science datasets and science parameters. Through its services, and the [NASA Worldview] client, GIBS enables interactive exploration of NASA's Earth imagery for a broad range of users. The data and imagery are generated within 3 hours of acquisition through the [NASA LANCE] capability. Esri and NASA Collaborative Services This visualization is made available through an ArcGIS image service hosted on Esri servers and facilitates access to a NASA GIBS service endpoint. For each image service request, the Esri server issues multiple requests to the GIBS service, processes and assembles the responses, and returns a proper mosaic image to the user. Processing occurs on-the-fly for each and every request to ensure that any update to the GIBS imagery is immediately available to the user. As such, availability of this visualization is dependent on both the Esri and the NASA GIBS services.