Since 2021, Landsat 8 and 9 have been used for nighttime imaging on their ascending orbit paths, supplementing standard daytime acquisitions. The USGS reports a significant rise in special requests for this nighttime data.
Key Applications
Volcano monitoring: Nighttime thermal infrared imagery helps detect and monitor thermal features. Dr. R. Greg Vaughan discovered a new thermal area in Yellowstone National Park using a 2017 Landsat 8 image.
Wildfire monitoring: Shortwave infrared bands can detect intense heat from active fires, supporting decision-making by agencies like the Pacific Northwest National Laboratory.
Polar ice monitoring: The Landsat Extended Acquisition of the Poles (LEAP) campaign routinely collects winter imagery to track ice sheet changes and surface temperatures.
Other uses: These include monitoring gas flares for the oil and gas industry, mapping urban heat islands, and surveying volcanic activity in Iceland.
Technical Details
- Nighttime imaging is possible because the instruments are always on; recording occurs when scheduled.
- Visible bands are less useful in darkness, but thermal infrared and shortwave infrared bands provide valuable data.
- Twilight imaging at high latitudes is highly effective due to the high reflectivity of snow and ice.
- Nighttime data volumes are lower than daytime, allowing efficient downlink to ground stations.
"We're populating the Landsat archive with long-term image data records that are helpful for not only quantifying changes on the Earth's surface right now, but in the past and in the future."
— Dr. Christopher Crawford, Landsat Project Scientist at USGS EROS
Dr. Crawford noted that nighttime imaging requests have increased, driven by needs in volcano, wildfire, and ice research.
Dr. R. Greg Vaughan of the USGS Astrogeology Science Center emphasized the value of regular nighttime acquisitions for his work on active volcanoes.