oastline near the river delta, as well as farther south along Laizhou Bay. The dark geometric shapes along the coast were built on what were once tidal flats. These ponds hold shrimp and other types of seafood.
Landsat imagery is useful in providing historical records of the changes taking place on the Earth’s surface, and future acquisitions will allow scientists to help in protecting the delta’s natural wetlands, while meeting the demands of development along the shoreline.
As a 3-year drought continues in the western United States, water levels have been dropping in many California reservoirs, leading to emergency water use restrictions across the state.
These two Landsat images show the changing shoreline of Shasta Lake reservoir in northern California over the past three years. The first image was collected in September 2011 and shows the shoreline when the reservoir’s water levels were at 77 percent of total capacity. The tan colors in the September 2014 image show the change in shoreline. Even though snowmelt slightly increased the lake level earlier in 2014, the reservoir was still at only 27 percent capacity when this more recent image was acquired.
The lower right portion of the second image also shows a recent burn scar from the Gulch Fire. This fire was officially contained one day before the September 17 image was collected.
The images collected by Landsat are an important tool for monitoring changes to the earth’s surface, and can help support analysis related to water resources and other environmental conditions for affected communities.
Mapping Biodiverse Highlands with Satellite Imagery and Advanced Elevation Data September 23, 2014
A team from the USGS Earth Resources Observation and Science (EROS) Center produced a detailed land use/land cover map using Landsat satellite and 30-meter elevation data from the Shuttle Radar Topography Mission (SRTM) of the highlands along the Senegal-Guinea border. The Dindefelo Nature Reserve was created to protect the high biodiversity of this area, including chimpanzee habitat, which is closely correlated with topography. The map helps scientists visualize the resources within the reserve and the mounting human pressure on the natural landscapes that surround it.
The Landsat 8 image (left) of the study area coupled with the SRTM 30-meter data (center) provides a specialized view of the topography. The land cover map (right) shows the diverse habitats, including the locations of gallery forests. These narrow ribbons of dense trees follow watercourses and are indicated as purple shades on the land cover map. Gallery forests provide critical refuge for many species of plants and animals during the long, hot dry season. The maps are being used in a proposal by the Jane Goodall Institute to Senegal and Guinea to extend the Dindefelo Nature Reserve south into the Guinea highlands.
Mapping these biodiverse highlands is one example that demonstrates the advantage of the more accurate elevation data from SRTM. For more information, see the USGS Top Story here.
Detailed Elevation Data—Niger River Delta September 23, 2014
Shuttle Radar Topography Mission (SRTM) data had previously only been available worldwide at 90-meter resolution. The National Geospatial-Intelligence Agency (NGA), NASA, and USGS are now releasing a newly processed, global SRTM 30-meter dataset.
The above images show an example of the difference between the 90-meter and 30-meter data of the Niger River Delta in western Africa. The Landsat image, also at 30-meter resolution, of the same area shows the extensive coastal estuaries, tidal flats, mangrove forests, and lowland rainforests of this part of southern Nigeria. More detailed elevation data are especially critical in such coastal settings that have small elevation changes.
For more information on the new SRTM elevation product, see the USGS Top Story here.
Coastal Flooding near Semarang City, Indonesia September 19, 2014
Coastal inundation is an ongoing concern for the region near Semarang, Indonesia. This area faces several different types of flood risk, d