Worldview Image of the Week

Power Outages in Houston, Texas

Image captured on 16 February 2021, by the VIIRS instrument, aboard the joint NASA/NOAA Suomi NPP satellite.

Power outages in Houston, Texas on 16 February 2021.

Houston, Texas with Power on 7 February 2021.

Night time images of Houston, Texas. These images were acquired on 7 and 16 February 2021 by the Day/Night Band of the Visible Infrared Imaging Radiometer Suite (VIIRS), aboard the joint NASA/NOAA Suomi National Polar orbiting Partnership (Suomi NPP) satellite. Houston's power outages were due to a winter storm that knocked out power to 1.4 million customers. Use Worldview's comparison tool to see the difference between Houston's night lights on 7 February and 16 February 2021.

This imagery layer was recently added to Worldview in December 2020. The Black Marble Nighttime At Sensor Radiance (Day/Night Band) layer is created from NASA’s Black Marble daily at-sensor top-of-atmosphere nighttime radiance product (VNP46A1). It is displayed as a grayscale image. The layer is expressed in radiance units (nW/(cm2 sr)) with log10 conversion. It is stretched up to 38 nW/(cm2 sr) resulting in improvements in capturing city lights in greater spatial detail than traditional Nighttime Imagery resampled at 0-255 (e.g., Day/Night Band, Enhanced Near Constant Contrast).

The ultra-sensitivity of the VIIRS Day/Night Band enables scientists to capture the Earth’s surface and atmosphere in low light conditions, allowing for better monitoring of nighttime phenomena. These images are also useful for assessing anthropogenic sources of light emissions under varying illumination conditions. For instance, during partial to full moon conditions, the layer can identify the location and features of clouds and other natural terrestrial features such as sea ice and snow cover, while enabling temporal observations in urban regions, regardless of moonlit conditions. As such, the layer is particularly useful for detecting city lights, lightning, auroras, fires, gas flares, and fishing fleets.

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Dataset doi: 10.5067/VIIRS/VNP46A1_NRT.001

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