estruction.
Because they only measure field plots once a decade, Forest Service crews may have a harder time grasping the enormity of the assault. With Landsat’s continuous monitoring, the size and timing of infestations become much clearer.
Mississippi River Floods Deep South March 29, 2016
Late winter storms March 10–12, 2016, drenched areas of Louisiana, eastern Texas, Mississippi, and Arkansas with up to 20 inches of rain, causing significant damage and evacuations.
Louisiana officials say the resulting flooding there is among the most widespread for any non-hurricane event ever seen. These images acquired by Landsat 8 clearly capture the scope of that historical inundation.
Though earlier storms in January had already pushed the Lower Mississippi River toward the top of its banks, the meandering waterway appears largely contained in the image on the left, acquired March 4, 2016. Sixteen days later, however, the satellite’s sensors reveal something much more dramatic.
In the center of the March 20 image, the deep blue floodwaters spill on to the landscape surrounding Vicksburg, MS. At the bottom center, the river is engorged just south of Natchez, MS, as it flows off the image on its way to Baton Rouge, LA.
Smaller tributaries west across the border in Louisiana show the impact of the drenching rains as well, testifying to the most widespread flooding in the region since Hurricanes Isaac (August 2012) and Katrina (August 2005).
When the Earth shook Alaska 52 years ago—on Good Friday, March 27, 1964—tsunamis wiped out entire villages. Landslides swept Anchorage neighborhoods into Cook Inlet. A collision of tectonic plates comprising the planet’s outermost layer had caused a 9.2 magnitude earthquake, the largest in U.S. history, and killed 131 people.
Aerial photographs archived at the USGS Earth Resources Observation and Science (EROS) Center capture the quake’s dramatic impact on Anchorage’s coastal boundaries. In the 1953 image, the Turnagain neighborhood west of the city’s downtown area is only beginning to emerge from the trees along the inlet. Eight years after the disaster, in 1972, the wooded shoreline has vanished, the bluffs now submerged in a sediment band created by the cataclysmic actions of the temblor. Yet extensive new development shows that Anchorage continued to expand in this area.
These are just two of the 6.5 million aerial photographs that span the last 80 years and are available on the USGS EarthExplorer Web site. Along with millions of other data files in the EROS archive that have been acquired from satellites, airborne radar, and the U.S. space program, these aerial photographs tell an important and compelling story about land cover that is ever changing, both in the United States and around the globe.
Landsat Reveals Water Use Dynamics in the San Joaquin Valley March 14, 2016
California’s San Joaquin Valley is one of the world’s most productive agricultural regions. Much of that productivity depends on the availability of water for irrigation. Recent prolonged droughts in California have underscored the importance of accurately monitoring changes and trends in water use in order to make well-informed water management decisions.
Scientists with the USGS Earth Resources Observation and Science (EROS) Center used Landsat images to quantify water use in the San Joaquin Valley over a 30-year period. A first step was to determine evapotranspiration (ET), which is water transpired by plants into the atmosphere as well as water that evaporates from the surrounding soil. ET can be used as a measure of water usage across a landscape. The scientists employed a computer model that incorporates Landsat imagery, including the Landsat 8 thermal band, along with climate data to estimate ET for every Landsat scene of the Valley from 1984 to 2014.
The team then integrated the ET results with precipitation and runoff data to create maps that reveal historical trends in water use and availability on irrigated basins in the Valley over the 30-year time period. Detailed enough to show individual fields, the maps d