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World of Change Satellite images showing how our world— forests, oceans, cities, even the Sun— has changed in recent decades. Read more
In the Andes Mountains, along the border between Chile and Argentina, lies Llullaillaco Volcano. With an elevation of 6,739 meters (22,109 feet) above sea level, the volcano is the world’s second-highest active volcano after Nevados Ojos del Salado, farther south in the Andes. Llullaillaco’s last recorded eruption occurred in 1877. Llullaillaco is a stratvolcano composed of alternating layers of hardened lava, solidified ash, and rocks ejected by earlier eruptions.
The Yukon River originates in British Columbia, Canada, and flows through Yukon Territory before entering Alaska. In southwestern Alaska, the Yukon Delta spreads out in a vast tundra plain, where the Yukon and Kuskokwim Rivers meander toward the Bering Sea. The Enhanced Thematic Mapper Plus on the Landsat 7 satellite acquired this natural-color image of the Yukon Delta on September 22, 2002. Looking a little like branching and overlapping blood vessels, the rivers and streams flow through circuitous channels toward the sea, passing and feeding a multitude of coastal ponds and lakes. The Yukon Delta is an important habitat for waterfowl and migratory birds, and most of the protected refuge is less than 100 feet (30 meters) above sea level. Over such low-lying, mostly treeless terrain, the rivers can change course frequently and carve new channels to find the fastest route toward the sea.
In March 2011, the Earth Observatory published images of a rare, deep depletion in the ozone layer over the Arctic. The images came from daily observations made by the Ozone Monitoring Instrument on NASA’s Aura satellite. A new study published in Nature uses a companion instrument on Aura, the Microwave Limb Sounder, to describe how and why the event looked a lot like the annual Antarctic “ozone hole.” MLS looks through the edge of Earth’s atmosphere to measure gases, in this case ozone and chlorine monoxide, one of the most dominant ozone-destroying gases.
Several rivers in southeastern Mexico spilled over their banks in late October, according to the Latin American Herald Tribune. The Usumacinta River alone damaged homes and croplands in multiple cities, and isolated rural areas by washing out roads. The governor of the state of Tabasco estimated that regional floods had affected 90,000 residents. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured these images on October 23, 2011 (top), and October 30, 2009 (bottom).
It is up to 18 miles (29 kilometers) wide and one mile (1.6 km) deep, and stretches 277 river miles (446 km). It is one of the greatest natural wonders of North America and perhaps the entire world. And thanks to a joint American and Japanese science team, we now have a new perspective on the Grand Canyon and many other topographic features of the planet. The image above shows the eastern part of Grand Canyon National Park in northern Arizona, near 36 degrees north latitude and 112.1 degrees west longitude. It is a composite of two pieces: a synthetic natural color image captured on July 14, 2011, draped over a three-dimensional model of the area. The images and stereoscopic data behind the model were acquired by the Advanced Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra spacecraft.
The southern United States is known for its distinctive cultural and historical identity within the country, including distinct music, cuisine, literature, and social customs. The U.S. Census Bureau defines “The South” as including the states of Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and West Virginia. This astronaut photograph from the International Space Station highlights the southeastern part of the South at night, including the eastern Gulf of Mexico and lower Atlantic Seaboard states. The view is part of a time-lapse series of images that extends from just southwest of Mexico to northeast of Newfoundland, Canada. New sequences from the Space Station are regularly posted on the Crew Earth Observation videos page.
In September 2011, sea ice covering the Arctic Ocean declined to the second-lowest extent on record. Satellite data from NASA and the National Snow and Ice Data Center (NSIDC) showed that the summertime ice cover narrowly avoided a new record low. The image above was made from observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA’s Aqua satellite. The map—which looks down on the North Pole—depicts sea ice extent on September 9, 2011, the date of minimum extent for the year.
In a matter of five days, the Philippines and southeastern Asia were hammered by two intense tropical storms in late September and early October 2011. Several months worth of rain fell within a week—a deluge even by tropical standards—on Luzon in the northern Philippines, as well as in northern Vietnam and the Chinese island of Hainan. This image shows average rainfall totals in the Western Pacific from September 26 to October 2, 2011, when Typhoon Nesat and Super Typhoon Nalgae passed through. The heaviest average rainfall—more than 350 millimeters or 14 inches—appears in dark blue. Localized rainfall amounts could be significantly higher. The lightest rainfall—less than 50 millimeters or 2 inches—appears in light green.
Some meteor impact craters, like Barringer Crater in Arizona, are easily recognizable due to well-preserved forms and features on the landscape. Other impact structures, such as Bigach Impact Crater in northeastern Kazakhstan, are harder to recognize due to their age, modification by geologic processes, or even human alteration of the landscape. At approximately five million years old, Bigach is a relatively young geologic feature.
When viewed from the International Space Station (ISS), the night skies are illuminated with light from many sources. For example, the Midwestern United States presents a nighttime appearance not unlike a patchwork quilt when viewed from orbit. The artificial light from human settlements appears with a characteristic yellow tinge. The green light of the aurora borealis also shines brightly in this view—even seeming to reflect off Earth’s surface in Canada. A small white patch of light is almost certainly lightning from a storm on the East coast (image top right). Part of the ISS appears across the top of the image.
A new satellite instrument is sending back detailed information about the health of Earth's ozone layer, the atmospheric gas that shields life from harmful levels of the Sun's ultraviolet radiation. The Ozone Mapper and Profiler Suite, or OMPS—one of five new instruments on the Suomi National Polar-orbiting Partnership (NPP) satellite—will add to a record of space-based ozone monitoring that dates back to 1978. The images above show the concentration of ozone in Earth's atmosphere above the South Pole on January 27, 2012. Measurements are expressed in Dobson Units, the number of molecules required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 0 degrees Celsius and a pressure of 1 atmosphere (the air pressure at the surface of the Earth). The ozone layer’s average thickness is about 300 Dobson Units, a layer that is 3 millimeters thick, or the height of two U.S. pennies stacked together.
September 18, 2010 August 20, 2011 acquired September 18, 2010 download large image (4 MB, JPEG, 3000x3000 - left) acquired September 18, 2010 download GeoTIFF file (16 MB, TIFF, 3000x3000)
Large fires burned throughout Australia’s Northern Territory on September 30, 2011, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image. The fires are marked in red. Fire fighters were monitoring 21 fires, said news reports, but many more are shown in the image. The fires are burning through thick grass in remote areas. The top image provides a closer view of three large fires around Alice Springs. The lower image shows a broader area of fire activity in central Australia.
Satellite imagery suggests that the eruption of Nabro Volcano, which began in June 2011, continues. The volcano is located on the edge of the Danakil Desert, a remote and sparsely populated area on the border between Eritrea and Ethiopia, and few eyewitness accounts of the eruption are available. Orbiting instruments such as the Advanced Land Imager (ALI) aboard Earth Observing-1 (EO-1), which acquired these images, may be the only reliable way to monitor Nabro. The images show the volcano in false-color (top) and natural-color (lower) on September 28, 2011. Heat from vents in Nabro’s central crater is visible as a red glow in the false-color image. Another hotspot about 1,300 meters (4,600 feet) south of the vents reveals an active lava flow.