Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery
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December 2, 2011
Intriguing Images of 2011

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Earth imagery is elevating our understanding of today’s interconnected world by providing unparalleled insights and transparency. The images on the following pages highlight just a few of the many ways remote sensing helped chronicle some of 2011’s noteworthy events.

 

A GeoEye-1 image collected March 3, 2011, reveals a mass of people at the Ras Ajdir crossing at Libya’s border with Tunisia.

Satellite Imagery Shows Libyan Refugee Crisis

During the first days of the Libyan uprising, as many as 4,000 refugees were crossing the Libya–Tunisia border daily. Satellite imagery collected in early March 2011 showed a provisional refugee camp set up at the Ras Ajdir border crossing with a capacity for 10,000 was overflowing with an estimated 20,000 to 30,000 refugees. Many tens of thousands were still trapped on the Libyan side of the frontier. By March 3, the situation was described as a logistical nightmare, with the World Health Organization warning of the risk of epidemics.

Massive Protests Lead to Egyptian Revolution

Cairo’s Tahrir Square was the focal point of the 2011 Egyptian revolution against former president Hosni Mubarak. More than 50,000 protesters first occupied the square onJan. 25, 2011. On Feb. 1, Al Jazeera reported that more than 1 million protesters gathered in and around the square. According to STRATFOR analysis, however, the real number of gathered protesters never exceeded 300,000 people. Despite its predominantly peaceful nature, the revolution wasn’t without violent clashes between security forces and protesters—at least 846 people were killed and 6,000 injured.

 

A high-resolution satellite image shows hundreds of thousands of protesters in Cairo’s Tahrir Square on Feb. 11, 2011, the day Mubarak resigned from office.

 

Satellite Imagery Supports Disaster Response in Japan

Satellite imagery provided detailed before-and-after perspectives following a devastatingMarch 11, 2011, earthquake and tsunami that struck Japan. Satellites revealed widespread destruction, including evidence of collapsed structures, extensive debris, massive flooding and damage to key infrastructure. Satellites also captured explosions and failures at nuclear facilities, documented the state of the country’s highways, and assessed damage at the main ports and refineries.

Imagery analysts combined TerraSAR-X post-disaster data over Japan with archived data to produce a detailed change analysis of the Sendai area.

Satellite imagery also allowed relief workers to see damage on a street-by-street basis, enabling in-country organizations to deliver aid and medical care and attempt to rescue those trapped in collapsed buildings. Additionally, as detailed in “GeoPDF Maps Accelerate Japan Disaster Damage Assessment,” page 28, satellite imagery has proved to be invaluable for cleanup and rebuilding efforts.

GeoEye posted several before-and-after “slider” satellite images on its Web site to reveal the extent of the devastation.

 

Lava Flows at Nabro Volcano

Located in the East African nation of Eritrea, the Nabro volcano began erupting explosively onJune 12, 2011. The powerful eruption sent plumes of ash streaming over North Africa and the Middle East, and pumped vast quantities of sulfur dioxide into the atmosphere. The eruption killed seven people, according to the Eritrean government.

 

For more than two weeks, a dense plume of water vapor, gas and ash concealed the summit of the Nabro volcano. Above, an EO-1 satellite image from June 29 finally provided a nearly unimpeded view of the summit, where lava flowed out of the erupting vent and down the volcano’s slope. At left, sulfur dioxide (SO2) emissions from the Nabro volcano eruption were observed by the Ozone Measuring Instrument on NASA’s Aura satellite. Because of the volcano’s remoteness, SO2 emissions were the first indication of the eruption.

Within a couple of weeks, the volcano eased into a quieter, lava-oozing phase, as shown in the accompanying image from the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite. The image shows the volcano in visible and infrared light (shortwave infrared, near infrared and green). The hot lava glows orange-red, fading to black as it cools. The long flow on the west side of the volcano is mottled with black, a sign that the surface is cooling. The lava to the east and south of the vent appears to be newer, as little of it has cooled.

Throughout the eruption, satellite images have been nearly the only source of new information about activity at the volcano. Detailed images like this one provide insight into how erupting lava is behaving. For example, volcanologists used previous ALI images to estimate how quickly the lava is moving and how thick the lava is.

 

 

2011 Tornado Season Deadliest in 75 Years

A large number of deadly tornadoes occurred in the United States during 2011. As of Nov. 3, 1,820 tornadoes were reported from which an estimated 550 people died, compared with 564 U.S. deaths from tornadoes during the 10 years prior combined.

Satellite images reveal the path of a devastating tornado that swept through Tuscaloosa, Ala., on April 27, 2011. This high-resolution satellite image captured the tornado’s path on April 29. Below, a false-color image collected May 4 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor on NASA’s Terra satellite clearly reveals a tornado track passing through Tuscaloosa, entering the image at lower left and exiting upper right. Vegetation appears as red, barren and developed areas (including the tornado track) as cyan/green, and water as various shades of blue. ASTER acquisitions on this date included numerous tornado tracks and were used by agencies to create maps of the affected areas.

It was also the deadliest year for tornadoes in the United States since 1936, due mostly to 324 deaths that occurred during an April 25-28 “Super Outbreak” of daily tornadoes across the Southeastern United States and 159 deaths as a result of the May 22 tornado that struck Joplin, Mo. April 27 was among the most prolific and destructive tornado days in U.S. history. Possibly the hardest-hit area was Tuscaloosa, Ala., where at least 32 people died. Estimates indicated that tornado may have been on the ground for 176 miles, with winds between 167 and 200 mph.

Heat Wave Underscores Earth’s Energy Imbalance

A summer heat wave left much of the United States sweltering in July 2011. On July 22, many cities from Virginia to Maine broke temperature records with highs between 100 and 108 degrees Fahrenheit (38 to 42 Celsius). The heat settled heavily over the South and Midwest as well. Both Texas and Oklahoma experienced their warmest month on record, and some cities experienced temperatures higher than 100 degrees Fahrenheit nearly every day of the month.

The western desert and southern plains are radiating the most heat in this image because the exposed rock and soil absorb and release heat directly. In other parts of the United States, rock and soil are covered with forests and grasslands where more energy from the sun evaporates water or causes plants to release water. Because more of the sun’s energy goes to evapotranspiration where plant growth is thick, the land absorbs and radiates less heat, thus appearing cooler in this image.

If the human eye could see the heat radiating out of the United States, it would look like the image at left. It’s a measure of outgoing longwave radiation (heat) as seen by the Clouds and the Earth’s Radiant Energy System (CERES) instrument on the Terra satellite onJuly 22, 2011, at the peak of the heat wave. The areas releasing the most heat are nearly red, while cooler areas are white. The coolest areas in the image are clouds.

Decades of measurements from CERES and similar instruments have revealed that Earth’s energy budget isn’t in balance. Earth is receiving more energy than it is sending back to space. This means that the planet must heat up—and already is heating up—to regain balance. Because heating affects temperature and evaporation, that change is encouraging more frequent heat waves and intense storms.

 

Looking Down on a Shooting Star

An astronaut photograph, taken from the International Space Station (ISS) while over China, provides the unusual perspective of looking down on a meteor as it passes through the atmosphere. The image was taken onAug. 13, 2011, during the Perseid Meteor Shower, one of the most dependable meteor shower displays, occurring every August. The Perseid meteors are particles that originate from Comet Swift-Tuttle; the comet’s orbit is close enough for these particles to be swept up by the Earth’s gravitational field every year.

 

The ISS Expedition 28 crew acquired this image with a Nikon D3S digital camera, using a 22mm lens.

Green and yellow airglow appears in thin layers above the limb of Earth, extending from image left to the upper right. Atoms and molecules above 50 kilometers in the atmosphere are excited by sunlight during the day, and then release this energy at night, producing primarily green light that is observable from orbit. Part of an ISS solar panel is visible at image upper right; behind the panel, a bright region indicates the sun low on the horizon.

London Prepares for the 2012 Olympics

A half-meter resolution satellite image collectedAug. 3, 2011, shows construction progress on London’s 2012 Olympic Stadium and other Olympic Park venues. London and the United Kingdom will host the 2012 summer Olympic and Paralympic Games—the world’s largest sporting events.

A high-resolution image of London’s Olympic site was collected by the GeoEye-1 satellite while flying 423 miles above Earth at an average speed of 17,000 mph, or four miles per second.

The Games will feature 302 events in 26 sports and cover 39 disciplines. The Olympic Stadium is located at Marshgate Lane in Stratford in the Lower Lea Valley and has the capacity to seat approximately 80,000 visitors, making it temporarily the third largest stadium in Britain. The Opening Ceremony isJuly 27, 2012, and the Closing Ceremony isAug. 12, 2012—both to be held at the Olympic Stadium.

 

Hurricane Irene Hammers the Northeast

NOAA’s GOES-13 satellite captured this stunning visible image of Hurricane Irene 28 minutes before it made landfall in New York City. Shadows in Irene’s clouds indicate the bands of thunderstorms that surround now tropical storm Irene.

Irene caused flooding from the Carolinas to the northeastern states. The heaviest rainfall totals of more than 225 mm (~8.9 inches) were located in North Carolina, where Irene first made landfall in the United States. Heavy rainfall, resulting in flooding, also was evident in the Tropical Rainfall Measuring Mission (TRMM) rainfall map in northeastern states along the hurricane’s track.In the wake of heavy rains from Hurricane Irene, sediment filled many rivers and bays along the U.S. East Coast. New York’s Hudson River and estuary was no exception. In this true-color Landsat 5 satellite image, acquired Aug. 31, 2011, pale green and tan water flows past Manhattan and mixes with the darker waters of New York Harbor and the Atlantic Ocean.

As Hurricane Irene made its way up the Eastern seaboard, bringing with it 100 mph winds and up to 15 inches of rain in some areas, as many as 65 million people braced themselves for a weekend of extreme weather. Irene made landfall over North Carolina’s Outer Banks on Aug. 27 as a Category 1 hurricane, the first U.S. landfall hurricane since Hurricane Ike in 2008. Although Irene was downgraded to a tropical storm as it moved up the East Coast, considerable damage occurred in upstate New York and Vermont, which suffered from the worst flooding in centuries. NASA reported that Hurricane Irene’s cloud was more than 600 miles wide, and the storm stretched about one-third the length of the entire U.S. Atlantic coast. Remarkable images from NASA and NOAA satellites show the storm’s enormity.

 

Ground Zero Restoration Under Way

Even from space, two acre-sized 9/11 Memorial pools can be made out where the Twin TowersUpon its completion in 2013, the site’s One World Trade Center (above) will be the tallest building in the United States, with its radio antenna reaching a symbolic height of 1,776 feet (541.3 m) in reference to the year of American independence. More than 400 trees are planned for the new World Trade Center plaza (below).

A high-resolution satellite image collected Aug. 5, 2011, shows work under way at the new World Trade Center complex in lower Manhattan. Along with One World Trade Center, the complex’s lead building, the site will feature three other high-rise office buildings and the 9/11 Memorial and Museum. On Sept. 11, 2011, a dedication ceremony was held at the 9/11 Memorial and Museum, commemorating the 10th anniversary of the attacks. The memorial officially opened to the public on Sept. 12, 2011, and the museum will open on or around Sept. 11, 2012. Construction progress is available at the official World Trade Center website, www.wtc.com.

 

Antarctic Mosaic Comprises More Than 3,000 RADARSAT-2 Images

The RADARSAT-2 pole-to-coast Antarctic mosaic was created by MDA in cooperation with the Canadian Space Agency as part of the International Polar Year.

MDAInformation Systems Group’s new image of Antarctica, developed in coordination with the Canadian Space Agency for the International Polar Year (2007-08), is a unique compilation of more than 3,150 RADARSAT-2 images that comprise a single pole-to-coast map covering all of Antarctica. The mosaic provides a detailed representation of the Antarctic ice sheet, showing subtle topographic features from the South Pole to the Antarctic coastline.

Used in conjunction with the RADARSAT-1 Antarctic mosaic produced in 1997 by researchers at the Byrd Polar Research Center at The Ohio State University, along with Vexcel, the Alaska SAR Facility, the Canadian Space Agency and NASA, the RADARSAT-2 Antarctic mosaic provides a unique view of the approximately decadal change in the Antarctic ice sheets. The image provides insight into the current condition of the Antarctic ice sheets, as well as the nature and rate of change in the Antarctic environment.

In addition, the image provides a useful map to support operations needing detailed information to understand the surface and sub-surface features of the Antarctic ice. The knowledge gained from this important scientific mission will enhance the collective information being compiled worldwide on the Antarctic, providing a deeper understanding of the relationship between ice and climate change.

NASA’s “Salt of the Earth” Aquarius Reveals First Map

NASA’s new Aquarius satellite produced its first global map of the salinity, or saltiness, of Earth’s ocean surface, providing an early glimpse of the mission’s anticipated discoveries. Its rich tapestry of global salinity patterns demonstrates Aquarius’ ability to resolve large-scale salinity distribution features clearly and with sharp contrast.

The first global map of the salinity of Earth’s ocean surface produced by NASA’s new Aquarius satellite reveals a rich tapestry of global salinity patterns, demonstrating Aquarius’ ability to resolve large-scale salinity distribution features clearly

The new map is a composite of the first two and a half weeks of data after Aquarius became operational onAug. 25, 2011. The numerical values represent salt concentration in parts per thousand (grams of salt per kilogram of sea water). Yellow and red colors represent areas of higher salinity, with blues and purples indicating areas of lower salinity. Areas colored black are gaps in the data. The average salinity on the map is about 35.

The map reveals predominantly well-known ocean salinity features, such as higher salinity in the subtropics, higher average salinity in the Atlantic Ocean compared with the Pacific Ocean and Indian Ocean, and lower salinity in rainy belts near the equator, in the northernmost Pacific Ocean and elsewhere. These features are related to large-scale patterns of rainfall and evaporation over the ocean, river outflow and ocean circulation. Aquarius will monitor how these features change over time and study their link to climate and weather variations.

LiDAR Enhances 3-D Capabilities for Warfighters

Overflights the U.S. Army conducted over Afghanistan and Iraq raised the profile of light detection and ranging (LiDAR) data in 2011, as analysts, commanders and warfighters continue to explore its utility for a variety of tasks, from mission planning to training.

E3De, an interactive geospatial software environment, was used to derive photorealistic 3-D visualizations and automatically extract buildings from BuckEye LiDAR data of Kandahar, Afghanistan.

LiDAR has an advantage over some other geospatial technologies because it provides accurate elevation data. Under the right circumstances, it also can detect hidden objects. But LiDAR’s true value as a military and intelligence tool is its ability to enhance other sensor data used by analysts, planners and commanders. For example, the U.S. Army Geospatial Center’s BuckEye program has evolved through urban warfare missions in Iraq and Afghanistan to collect 1-meter post-spacing terrain data with 10-centimeter color imagery (or better, if possible) that’s extremely accurate over entire operational areas. BuckEye provides a high-resolution 3-D foundation data layer on which  

 

RapidEye Captures Underwater Volcanic Eruption

RapidEye satellite images feature a gigantic stain visible on the surface of the Las Calmas Sea, resulting from a submarine eruption out of the coast of El Hierro, Spain. The eruption occurred 1,200 meters below sea level onOct. 10, 2011. Built mostly from a shield volcano, the island off the Atlantic coast of North Africa has been rocked by thousands of tremors and earthquakes since July 2011.

The recent eruption is the first in the island chain in nearly 40 years. A milky green plume in the water stretches 25-30 kilometers at its widest point and is about 100 kilometers long, from a large mass near the coast to thin tendrils as it spreads to the southwest. The plume is likely a mix of volcanic gases and a blend of crushed pumice and seafloor rock.

 

The underwater plume of volcanic debris persisted for more than two weeks and was mixed and dispersed by ocean surface currents.

 
 Refugee Camps Expand in Kenya

A major humanitarian crisis has been ongoing in northeast Africa for years. Now drought and intensified violence in Somalia have increased the number of refugees in camps along the Kenya-Somalia border.

A 2011 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scene reveals the expansive refugee camps in the vicinity of Dadaab, Kenya, and the adjacent Hagadera refugee camp.

The Office of the United Nations High Commissioner for Refugees reported onOct. 4, 2011, that nearly half a million displaced people were residing in the Dadaab camps. Many perish before reaching the camps, but about 1,000 new arrivals add to the support burden every day.

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