Category: EOG

By Tamara Sparks

The island-wide power outage caused by a fire at a power plant in Puerto Rico is visible in satellite imagery from the VIIRS day night band. Widespread loss of lighting on April 7, 2022, indicated in red, is seen across the island, although there are areas with typical lighting levels, seen in yellow. Cloud cover over the island is minimal, so the decrease in lighting is not due to clouds. In contrast, nearby US and British Virgin Islands have stable lighting, except for areas with cloud cover.

By David Hsu

Most cities in Ukraine are still in the dark – except those in easter Ukraine near Donetsk and Luhansk in the regions under Russian control. Two noticeable clusters of new lighting surrounding Chernihiv and Bucha, suggesting Russian forces making their way toward Kyiv. There were also some activities seen in Belarus near southern border.

For past images and latest update on Ukraine, visit the dedicated page here.

By Elijah Mt. Castle

By Feng Chi (David), Hsu

Kyiv experienced a horrifying night on 2/26. The oil depot near Vasylkiv Air Base was on fire creating extremely large fire. EOG was able to detect the event with both VNF and VNL from the thermal signature and visible light it created. Under curfew, most cities in Ukraine are much dimmer than they used to be. But we still see some places being particularly bright. Such as Chernobyl Nuclear Power Plant and Buryakivka radioactive waste site near the northern border. There are some other places exhibiting light where normally dark. We do not know what is being the source of light.

The Earth Observation Group (EOG) pioneered the development of monthly and annual global nighttime light products from low light imaging data collected by meteorological satellite sensors. Initially with data from the U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) and later with day / night band (DNB) data from the Visible Infrared Imaging Radiometer Suite (VIIRS).  EOG’s approach features a cascading series of filtration steps to exclude sunlit, moonlit, stray light and cloudy pixels.  The annual sets are then filtered to remove outliers (biomass burning, High Energy Particle (HEP) detections, some aurora) and finally the background is zeroed out.  What remains are primarily surface lighting features.

Using this formula EOG has produced a total of 57 annual and 584 monthly nighttime light products over the past two decades (Table 1). These are available on an open access basis from: https://payneinstitute.mines.edu/eog/nighttime-lights/.  EOG’s nighttime lights product are widely used by researchers around the world and have resulted in thousands of peer review publications.  Google scholar lists 2500+ papers based on VIIRS nighttime lights and 5600+ papers based on DMSP nighttime lights.

Despite these successes, we are aware of the flaws and shortcomings of the products.  Users take the products and use them as-is, often without visual inspection, leading to erroneous results and skepticism on product validity. There are clear pathways for product improvement that would benefit large numbers of researchers and provide societal benefits.

By Tamara Sparks

VIIRS Nightfire detected the Trinity Spirit, a floating oil production, storage, and offloading vessel, which exploded and caught fire off the coast of Nigeria early on Feb 2, 2022. The Suomi NPP satellite overpass at 00:47 UTC first detected the blaze, with an average temperature of 1043K for detections in the area. Almost an hour later at 01:36 UTC, the NOAA-20 satellite saw the fire burning hotter, averaging 1410K. These temperatures are lower than the average gas flaring temperature at the site, 1718K. Reporting says the site had been inactive prior to this incident, which is confirmed by the VNF flaring temporal profile showing very little flaring activity since early 2020.

By Elijah Mt. Castle

Wolf Volcano, the largest peak on the Galapagos Islands, has been erupting since January 6th, 2022. The volcano is 1.7 km tall and is around 1000 km from mainland South America. Ecuador’s Emergency Operations Committee said there was no risk to human life or the environment. Eight people were evacuated from Isabela island where the volcano is located. These were park employees and scientists studying the pink iguanas native to the island. Pictured are the VNF detections for January 7th – January 24th, 2022. The more pronounced the color the longer that area has been burning. Also pictured is the VIIRS SNPP Day/Night Radiances for January 7th.

By Elijah Mt. Castle

Multiple wildfires in Sequoia National Park have burned a total of 43,375 acres. The park is home to the world’s largest tree by volume, the General Sherman Tree. Sequoia trees are the largest species of trees by volume and can live to be over 2,000 years old. To protect the Tree and other large ancient trees, firefighters have wrapped the base of the trunks with fireproof blankets. Strict fire management practices have thinned smaller trees and brush to keep the fire low to the ground and not kill the large trees. Sprinkler systems have been set up to protect the trees and structures inside of the park. A preliminary assessment of the sequoia trees may take days due to the difficult terrain. As of now the fire has not damaged the General Sherman Tree. Pictured are the VNF detections for September 15th-19th 2021. Along with the SNPP VIIRS day/night band radiances for September 19th.