Black Marble Nighttime Blue/Yellow Composite (VIIRS / Suomi-NPP)
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Visualization Overview This visualization represents a global "false color" band combination (Red = DNB, Green = DNB, Blue = Inverted M15) of data collected by the VIIRS instrument on the joint NASA/NOAA Suomi-NPP satellite. The intended use of the imagery is for identifying nighttime lights from cities, fires, boats, and other phenomena. At its highest resolution, this visualization represents the underlying data scaled to a resolution of 500m per pixel at the equator. The algorithm to combine the VIIRS DNB and M15 bands into an RGB composite was originally designed by the Naval Research Lab and was subsequently incorporated into NASA research and applications efforts. As you will see, nighttime city lights appear in shades of yellow, while clouds appear in shades of blue to yellow/white as the illumination from the moon changes over the lunar month. Hence, this visualization is colloquially referred to as a "blue-yellow RGB." The following guidelines and limitations of use will aid in understanding this visualization. Interpretation of both the presence and relative brightness of the city lights will be affected by the lunar cycle. This composite offers a qualitative assessment of the light conditions and should not be used as the sole source of information concerning power outages. During bright moonlight conditions, moonlight reflected from cloud tops and the land surface may also provide a yellow hue to those features. Comparisons of cloud-free conditions before and after a period of significant change, such as new city growth, disasters, fires, or other factors, may exhibit a change in emitted light (yellows) from those features over time. Multi-Spectral Bands At its highest resolution, this visualization represents the underlying data scaled from its native 750m per pixel resolution to 500m per pixel at the equator. 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) DNB Visible (reflective) 0.5 - 0.9 750 DNB Visible (reflective) 0.5 - 0.9 750 M15 (Inverted) Longwave IR 10.26 - 11.26 750 Temporal Coverage By default, this layer will display the imagery currently available for today’s date. This 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. Currently, this layer is available from present back to November 24th, 2015. In the coming months, this will be extended to the start of the mission (October 28th, 2011). Data Access This visualization is generated from hourly and daily Near-Real Time versions of the "VIIRS/NPP Daily Gridded Day Night Band 500m Linear Lat Lon Grid Night" (VNP46A1_NRT) data product distributed by the Land, Atmosphere Near real-time Capability for EOS (LANCE). A standard quality version of the data product (VNP46A1), which is distributed by the Level-1 and Atmosphere Archive & Distribution System Distributed Active Archive Center (LAADS DAAC), is also available within 1-2 days of acquisition. You may use the Earthdata Search client to search for near real-time and science quality data files and associated documentation and services. Additionally, you may use the Worldview Snapshots tool to download custom images in a GeoTIFF , JPEG, PNG, or KMZ format for offline use. 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.



