7. Temporal Analysis of Satellite Images

2021-02-25. Fleets of radar satellites are measuring movements on Earth like never before. By Julia Rosen, Science Magazine. Excerpt: East Africa ...the geologically active region has also given birth to dozens of volcanoes. Few have been monitored for warnings of a potential eruption, and until recently, most were believed to be dormant. Then, Juliet Biggs decided to take a closer look—or rather, a farther look. Biggs, a geophysicist at the University of Bristol, uses a technique called interferometric synthetic aperture radar (InSAR) to detect tiny movements of Earth’s surface from space. In a series of studies, she and her co-authors analyzed satellite data on the East African volcanoes. According to their latest results, which were published last month, 14 have been imperceptibly growing or shrinking in the past 5 years—a clue that magma or water is moving underground and that the volcanoes are not completely asleep. ...After data showed that the Corbetti volcano, which abuts the fast-growing city of Hawassa, Ethiopia, is inflating steadily at a rate of 6.6 centimeters per year, Biggs’s Ethiopian colleagues included it in the country’s geological hazard monitoring network. ...Individual GPS stations can track surface movements of less than 1 millimeter, but InSAR can measure changes almost as subtle across a swath hundreds of kilometers wide. ...With InSAR, scientists are tracking how ice streams flow, how faults slip in earthquakes, and how the ground moves as fluids are pumped in or out.... [https://www.sciencemag.org/news/2021/02/fleets-radar-satellites-are-measuring-movements-earth-never] See also A technique to track Earth’s subtle movements with orbiting radars is heating up, by Meagan Cantwell, Science Magazine, Mar 5, 2021.

2021-01-05. It Spied on Soviet Atomic Bombs. Now It’s Solving Ecological Mysteries. By Marion Renault, The New York Times. Excerpt: ...the Corona project, which launched classified satellites in the 1960s and ’70s to peer down at the secrets of the Soviet military... gathered approximately 850,000 imagesthat were kept classified until the mid-1990s. ...Modern ecologists chronicling precious or lost habitats have given second life to the Corona images. Paired with modern computing, the space-based snapshots have helped archaeologists identifyancient sites, demonstrated how craters left by American bombs during the Vietnam War became fish ponds and recounted World War II’s reshaping of Eastern Europe’s tree cover.... [https://www.nytimes.com/2021/01/05/science/corona-satellites-environment.html]

2020-07-06. Five Things Spy Satellites Have Taught Us About Earth. By Jenessa Duncombe, Eos/AGU. Excerpt: Long before we had satellites beaming terabytes of data back to Earth, we had covert spacecraft the size of school buses snapping photos on rolls of film 50 kilometers long. ...KH-9 Hexagon, a spy satellite program launched by the U.S. National Reconnaissance Office (NRO) to surveil the Soviet Union between 1971 and 1986. Hexagon was just one in a line of covert Cold War missions managed by U.S. intelligence services, and some credit these services for helping the superpowers avoid engaging in direct conflict. In 2002, the U.S. government declassified the images from Hexagon, and since then, scientists have mined the photos to reveal changes in the world around us. The declassified images are incredibly detailed. Phil Pressel, who worked as an engineer for the company that designed Hexagon’s cameras, said the images were “much better than Google Earth.” The cameras captured objects as small as 0.6 meter wide and shot the scenery from an angle, instead of like other satellites that imaged the Earth directly from above.  ...1. Himalayan Glaciers Are Rapidly Melting ...2. Reindeer Are Losing Herding Ground in Finland ...3. Landslides Are Encroaching on Farms in Peru ...4. Seismic Hazards Have Been Uncovered in Eastern Iran ...5. A Volcano Is on the Move in Iceland... [https://eos.org/articles/five-things-spy-satellites-have-taught-us-about-earth]. 

2020-06-26. Six Ways Satellites Tracked COVID-19. By Jenessa Duncombe, Eos/AGU. Excerpt: A new database reveals dimmer cities, empty farming fields, and vacant ports. Three space agencies have released a database to help the public and policy makers trace the worldwide impact of the coronavirus. NASA, the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA) have collaborated to provide an online portal with regularly updated metrics. ...At least 17 satellites are being actively used in the dashboard, and others will join in the future. ...1. The Asparagus Crop Dropped by 30% in Germany. ...2. Light Pollution Intensified at a Medical Center in San Francisco. ...3. Beijing Factories Made Fewer Cars, and Singapore Patient Parking Rose. ...4. Nitrogen Dioxide Slashed by Half in Europe. ...5. Shipping Ports in New York Sat Empty. ...6. Carbon Dioxide in Beijing Fell, Then Boomeranged Back.... [https://eos.org/geofizz/six-ways-satellites-tracked-covid-19] For GSS Digital Earth Watch (https://sites.google.com/a/globalsystemsscience.org/digital-earth-watch/). 

2019-05-02. The International Space Station has found its scientific calling. By Paul Voosen, Science Magazine.

2015-10-19. Daily Views of Earth Available on New NASA Website. NASA Release 15-199.

2013-10-22.  Time is ripe for fire detection satellite, say Berkeley scientists.  Robert Sanders, UC Berkeley News Center.

23 October 2007. SOUTHERN CALIFORNIA WILDFIRES BURN OUT OF CONTROL: NEW NASA SATELLITE IMAGES SHOW FIRES' RAPID GROWTH. By Laura Spector, NASA Goddard Space Flight Center. Excerpt: NASA satellites continue to capture remarkable new images of the wildfires raging in Southern California. At least 14 massive fires are reported to have scorched about 425 square miles from north of Los Angeles to southeast of San Diego.
The latest images, captured by NASA satellites on the afternoon of October 22, show the thick, billowing smoke coming off the numerous large fires and spreading over the Pacific Ocean.
Dry, drought-stricken vegetation and Santa Ana winds, which can reach hurricane speeds, have contributed to the devastating effect of these blazes.... According to news reports, almost 700 homes have been destroyed and hundreds of thousands of residents have been forced to evacuate.
...A pair of images, depicting the area around Los Angeles on October 21, 2007, shows just how quickly the fires grew. According to the National Interagency Fire Center, the blazes have burned over 84,000 acres since they began over the weekend. Thousands of residents have been evacuated from their homes and a state of emergency has been issued for 7 California counties.

July 15, 2002, Urbanization's Aftermath -- Using satellite images of city lights at night, [a group of researchers at NASA's Goddard Space Flight Center led by biologist and remote sensing specialist Marc Imhoff] constructed a map of the urbanized areas of the United States. They then retrieved vegetation density readings of present day American cities as well as simulated readings of the landscapes that pre-dated these cities. By combining the vegetation data with the urbanization maps, Imhoff was able to calculate the effects of urbanization on many types of ecosystems across the country.


Project Gigalopolis: Urban and Land Cover Modeling

"World of Change" on the Earth Observatory website has time series of satellite images for the following:

  • Antarctic Sea Ice
  • Arctic Sea Ice
  • Larsen-B Ice Shelf
  • Amazon Deforestation
  • Mesopotamia Marshes
  • Severe Storms
  • Urbanization of Dubai
  • Mountaintop Mining, West Virginia
  • Yellow River Delta
  • Drought Cycles in Australia
  • Antarctic Ozone Hole
  • El Niño, La Niña, and Rainfall
  • Burn Recovery in Yellowstone
  • Global Biosphere
  • Shrinking Aral Sea
  • Solar Activity