The Landsat program is the longest running space imagery program, with satellites in operation since 1972. Through the decades, the imagery program, originally designed to study Earth’s landmasses, has now made contributions to a number of fields, ranging from the natural to the social sciences.
Landsat 9 Data
Starting from February 10, 2022, Landsat 9 data was made publicly available through the United States Geological Survey (USGS), which is co-supporting Landsat 9 with NASA.
Landsat 9 is the latest satellite to bear the Landsat name; the satellite was launched in September 2021 and has now become fully operational after undergoing some initial tests.
The USGS will now make available Level 1 and Level 2 data from Landsat 9, that is uncorrected and corrected atmospheric data and surface temperature data.
There are two main instruments carried by Landsat 9, which are the Operational Land Imager 2 (OLI-2) and the Thermal Infrared Sensor 2 (TIRS-2). The OLI–2 is used to capture visible, near-infrared, and shortwave-infrared bands at 30-m resolution. TIRS-2 measures thermal infrared radiation from the Earth’s surface, with the panchromatic band measuring features at 15 m resolution. The radiometric resolution in the OLI-2 instrument is also of superior quality over Landsat 8 (14-bit quantization vs. 12-bit), which enables a broader range of potential feature detection.[1]
False color image of Anchorage, Alaska acquired by Landsat 9 on November 20, 2021. This composite satellite image was created by combining infrared, red, and blue wavelengths. Image: USGS, Landsat 9, public domain.
The goal of Landsat 9 is to provide resource management and climate science information, including on land surface, coastal waters, and surface water data. While Landsat 9 will provide new Level 1 and 2 imagery, the data can also be used in tandem with the ongoing Landsat 8 program so that regions are covered every 8 days of satellite orbit.[2]
Multi-decadal Earth Observation Data
One of the benefits of the now 50-year record of Earth observation through the Landsat program is we now have decadal-scale data capture demonstrating climate and human-induced change across the Earth. The long-lived data allow measurements on how rapidly our planet is changing in a manner not previously possible.
Governments and aid agencies have been able to utilize Landsat data to monitor areas for change or document areas that need the most assistance due to natural or human-induced changes.[3]
Landsat 9 images of Hawaii’s Kilauea Volcano from January 25, 2022. The image on the left shows Landsat surface reflectance product. The image on the right was created with Landsat 9’s Landsat surface temperature product (temperatures measured in Kelvin). Images: Michelle Bouchard, USGS, public domain.
While long-term monitoring of environmental change is perhaps among the most well-known benefits of the Landsat program, there are many others. Disciplines and stakeholders as diverse as agriculture, forestry, urban science, human health, natural resources management, public safety, homeland security, climate research, and others have been able to benefit from Landsat data.
As an example, imagery from 2011 was able to document disasters affecting over 200 million people, showing broad landscape views of regions and impacts on them from different events such as fire or severe storms using infrared and natural light.[4]
In another stakeholder area, water scarcity has increasingly become a problem for nearly 1.8 billion people. Landsat imagery has been used to document this change and enable conservation plans to mitigate rapidly diminishing resources.[5]
Users of Landsat Data
The Landsat program has provided both free and commercial data now for more multiple decades. Popular platforms such as Google Earth or individual research scientists have utilized its data. Landsat has also been an influential program, with many commercial satellites and those sponsored by other agencies, such as the European Space Agency, developing systems that often are compared or based on Landsat systems.
The greatest percentage of Landsat data users are scientists (48%), agricultural specialists (23%), and resource managers (13%). In just four years (2016-2020), downloads doubled between 50 million to 100 million scene downloads.
While the future of the Landsat program is unclear, there are already scoping plans for Landsat 10, which can take the program well into this century with more Earth observation data collection. Potential changes to future satellite systems include increase image resolution, providing greater image captured per day, reducing the time between images for locations, increase the depth and variety of infrared frequencies, or improving on the overall satellite design (e.g., develop smaller or adaptable satellites).[6]
The Landsat program is perhaps the most successful imaging program in human history. It has also evolved to become critical to a variety of stakeholders and research endeavors. As the program continues, the long-lived data help to document our changing planet as we also plan to develop more resilient natural systems.
The Landsat program will likely continue to be needed in the future and recognizing this, the USGS and NASA have made Landsat 9, as well as earlier Landsat data, available for researchers.
References
[1] More background data on specifications on Landsat 9 can be seen here: Micijevic, E.; Haque, Md.O.; Scaramuzza, P.; Storey, J.; Anderson, C.; Markham, B. Landsat 9 Pre-Launch Sensor Characterization and Comparison with Landsat 8 Results. In Proceedings of the Sensors, Systems, and Next-Generation Satellites XXIII; Neeck, S.P., Kimura, T., Martimort, P., Eds.; SPIE: Strasbourg, France, October 10 2019; p. 51.
[2] For more on Landsat 9, including the characteristics of the satellite and data availability, see: https://www.usgs.gov/news/technical-announcement/usgs-opens-door-landsat-9-data.
[3] For a review of the Landsat program and application benefits, see: Wulder, M.A.; Loveland, T.R.; Roy, D.P.; Crawford, C.J.; Masek, J.G.; Woodcock, C.E.; Allen, R.G.; Anderson, M.C.; Belward, A.S.; Cohen, W.B.; et al. Current Status of Landsat Program, Science, and Applications. Remote Sensing of Environment 2019, 225, 127–147, doi:10.1016/j.rse.2019.02.015.
[4] For more on natural disasters mapped by Landsat and the benefits it has provided, see: https://landsat.gsfc.nasa.gov/benefits/disasters/.
[5] For more on how Landsat has been used in the areas of water, see: https://landsat.gsfc.nasa.gov/benefits/water/.
[6] For a report on the Landsat program and its potential application in the future, see: https://sgp.fas.org/crs/space/R46560.pdf.