Category: David Hsu

Blackout in Puerto Rico seen by VIIRS satellite

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.

Update on Ukraine in Dark – 2022/03/05

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.

Multiple Wildfires around Bay County Florida

By Elijah Mt. Castle

Multiple fires have been burning in Bay County Florida over the weekend. The Adkins Avenue fire started Friday in Bay County and is 35% contained having burned 841 acres. The Bertha Swamp Fire started on Friday in the neighboring Gulf County and crossed into Bay County Saturday, it is only 10% contained with a burn area of 9,000 acres. The fires are burning in an area decimated by Hurricane Michael in 2018. High winds have hampered firefighting abilities in Bay County with gusts up to 25 miles per hour(40 kilometers per hour). A third fire started Sunday and forced the evacuation of a state-owned veterans’ nursing home. The other fires have forced the evacuation of over 1,000 homes. Wildfire season in Florida is just beginning and there are around 150 wildfires burning throughout the state. Pictured are the VNF detections for March 6th, 2022. Also pictured are the VIIRS SNPP Day/Night Radiances for March 6th, 2022.

Satellite data provides insights about the unfolding conflict in Ukraine

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.

Earth Observation Group is the Pioneer in Global Nighttime Lights Product Generation

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:  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.



VNF Detects Oil Container Explosion

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.

Wolf Volcano Erupts

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.

Historical Fire Broke Out in Boulder

By Feng Chi (David), Hsu and Elijah Mt. Castle

The Marshall Fire in Boulder County burned more than 6,000 acres and leveled multiple subdivisions. The fire has been reported as the most destructive fire in Colorado history. One armed person has been arrested after threatening firefighters in the area, but as of now no cause has been determined by officials. According to a press conference Monday Jan 3rd, Boulder County law enforcement is working closely with the FBI and the ATF to determine the cause of the fire. The Marshall fire is one of two that started early in the morning on December 30th, 2021. The other fire was quickly put out, but strong winds over 100 mph and dry land caused the Marshall fire to spread rapidly. The National Weather service has reported that the Denver area has experienced the least amount of precipitation on record by over an inch. Fortunately, 8 inches of snow doused the affected area and helped prevent further damage to communities. Around 1000 homes have been destroyed in Boulder County. The Federal Emergency Management Agency (FEMA) has begun dispersing aid to the communities affected, including food and lodging. According to the President of Xcel Energy-Colorado there are approximately 400 homes still without power and 8000 without gas. 2 people are still reported missing, and at the time or writing no loss of life has been reported.


Live Stream of Press Conference:

Wildfires Threaten Largest Tree in the World

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.

Large Wildfires in California

By Elijah Mt. Castle

California has experienced several large wildfires over the month of August. The Dixie fire has been burning since July 13th and has grown over 910,000 acres. The Caldor fire started August 14th and has grown to over 216,000 acres. The River Complex and Monument Fire  both started on July 30th and are relatively smaller fires, 121,000 and 183,000 acres respectively. Numerous structures have been destroyed and thousands of residents have been displaced by the various fires. The Dixie Fire alone has destroyed 692 homes. The Monument Fire and River Complex were started by lightning. The other major fires are still under investigation. Dry conditions and wind have severely impacted fire suppression tactics over the month and all fires specifically listed are continuing to burn into September with some having predicted containment in October. Pictured are the VIIRS Night Fire detections for August with an associated temperature range. The darker the color in a location the longer a detection has been present. Also pictured is the VIIRS day/night band radiance for August 17th.