Lighthouse Atoll, Belize

The Lighthouse Atoll in the Belize Barrier Reef is featured in this image acquired on 29 March 2011 by Japan’s ALOS satellite. In the upper-central part of the image, an underwater sinkhole known as the Great Blue Hole appears as a dark blue circle. Surrounded by the shallow waters of the coral reef, the Great Blue Hole measures over 300 m in diameter and about 123 m deep. Formed when the sea level was much lower, rain and chemical weathering eroded the exposed terrain. Water later filled the hole and covered the area when the sea level rose at the end of the ice age.

Also visible in the image are two coral islands – green with vegetation – called cayes. The larger to the west is Long Caye, and the smaller Half Moon Caye is to the east.

This image is featured on the Earth from Space video program.

Photo credit: JAXA, ESA

Location of the April 20, 2013 Sichuan Earthquake

A powerful magnitude 6.6 earthquake struck Sichuan Province in southwest China on April 20, 2013, killing scores and injuring thousands, according to BBC News. Villages and roads near the epicenter were left in ruins, hampering rescue efforts. The earthquake occurred along the same fault that ruptured in 2008, killing tens of thousands and leaving some 5,000,000 people homeless. This perspective image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft, acquired in 2003, highlights the epicenter of the new earthquake. Vegetation is displayed in red; clouds and snow are in white.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Democratic Republic of Congo

An area in the northwest of the Democratic Republic of Congo is pictured in this image taken on 26 June 2011 by the French SPOT-4 satellite. Most of the lighter green areas are deforested, while the darker green are areas of dense – and possibly natural – vegetation. The lines cutting through the image are roads, many with structures built along them. Clusters of purple dots are larger settlements. A river snakes through the upper part of the image and below it there appears to be a square in light green. Judging by the precision of the outline, we can deduce that this is a patch of land that was either intentionally spared from deforestation or has been reforested.

This image is featured on the Earth from Space video program.

Photo credit: CNES/Spot Image/ESA

Note: The ESA has recently started to provide their best photographs in TIF format only. I personally converted this image to JPG format so that I could share it on this blog.

The Brazil-Bolivia Border

The river-delineated border between western Brazil's Acre province (upper left), and northwestern Bolivia's Pando Department (lower right), demarcates a remarkable difference in land use and development practices. Brazil has opened up this part of the rain forest to farming and settlement, producing the herringbone pattern of forest cutting. This part of Bolivia, on the other hand, preserves its native rain forest, untouched by development. The image was acquired July 2, 2008, covers an area of 42 by 45 km, and is located at 10.3 degrees south latitude, 67.2 degrees west longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

PROBA Vegetation

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Soon to be launched aboard the second VEGA flight from Kourou, PROBA V, V for Vegetation, is part of a series of small satellites made by ESA to demonstrate new technologies on orbit.

But this satellite - of only one cubic meter - will be an operational tool to monitor vegetation on Earth.

This video explains the mission of this innovative satellite mostly made in Belgium.

Video credit: ESA

Location of April 9 Iranian Earthquake

On April 9, 2013 at 11:52 GMT, a magnitude 6.3 earthquake hit southwestern Iran's Bushehr province near the town of Kaki. Preliminary information is that several villages have been destroyed and many people have died, as reported by BBC News. This perspective view of the region was acquired November 17, 2012, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft. The location of the earthquake's epicenter is marked with a yellow star. Vegetation is displayed in red; the vertical exaggeration of the topography is 2X. The image is centered near 28.5 degrees north latitude, 51.6 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Failaka Island

Kuwait's Failaka Island is located 50 km southeast of the spot where the Tigris and Euphrates Rivers empty into the Persian Gulf. For thousands of years the island has been a strategic prize to control the lucrative trade that passed up and down the Persian Gulf.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Severe Flooding in La Plata, Argentina

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft captured this view of severe flooding in La Plata, Argentina, on April 4, 2013. Torrential rains and record flash flooding has killed more than 50 and left thousands homeless, according to news reports. La Plata is located 20 miles (50 kilometers) from Buenos Aires. In the image, flooded areas east and west of the city appear in dark blue. A heavy sediment load gives the Rio Plata its yellow-brown color. The image covers an area of 15.8 by 16.7 miles (25.5 by 27 kilometers) and is located at 34.8 degrees south latitude, 58 degrees west longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Galeras Volcano, Colombia

This false-color image of Colombia's Galeras Volcano, was acquired by UAVSAR on March 13, 2013. A highly active volcano, Galeras features a breached caldera and an active cone that produces numerous small to moderate explosive eruptions. It is located immediately west of the city of Pasto. UAVSAR will precisely fly the same flight path over the volcano in 2014. By comparing these camera-like images taken at different times, interferograms are generated that reveal changes in Earth's surface caused by volcanic deformation.

UAVSAR is part of NASA's ongoing effort to apply space-based technologies, ground-based techniques and complex computer models to advance our understanding of Earth deformation processes, such as those caused by earthquakes, volcanoes and landslides. UAVSAR is also serving as a flying test bed to evaluate the tools and technologies for future space-based radars, such as those planned for a NASA Synthetic Aperture Radar (SAR) mission currently in formulation. That mission will study hazards such as earthquakes, volcanoes and landslides, as well as global environmental change.

Image credit: NASA/JPL-Caltech

Napo River in Ecuador and Peru

On March 17, 2013, NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) acquired synthetic aperture radar data over the Napo River in Ecuador and Peru. The image colors indicate the likelihood of inundation (flooding) beneath the forest canopy, which is difficult to determine using traditional optical sensors. Red and yellow shades indicate a high likelihood of standing water with emergent vegetation, blue and green shades are areas less likely to be inundated, and black indicates the open water areas of the Napo River. These data, which have already been transmitted to a field team working along the Napo River, will be used to guide field measurements during a second observation by UAVSAR on March 31, 2013. The image is a 8.7-mile-wide by 5.6-mile-long (14-kilometer-wide by 9-kilometer-long) segment of an image measuring more than 124 miles (200 kilometers) long. North is toward the upper right. The resolution is 20 feet (6 meters). UAVSAR data like these are helping scientists assess the effectiveness of using synthetic aperture radar data to study the inundation dynamics of this and similar rivers around the world.

Image credit: NASA/JPL-Caltech

Note: For more information, see NASA Flies Radar South on Wide-Ranging Expedition; also, PIA16942: NASA Sends Unmanned Aircraft To Study Volcanoes and Wetlands.

Samarra, Iraq

Radarsat-2 entropy image and archaeological map over the octagonal city plan of part of ancient Samarra, located about 130 km north of Baghdad, Iraq. These results were found by Nicole Dore using the remote sensing technique Polarimetric SAR in a collaboration between Italy’s La Sapienza and France’s Rennes 1 universities.

Image credit: Satellite image: VigiSAT; Map: A. Northedge, 2007 The Historical Topography of Samarra. Samarra studies I.

Akashi Kaikyo Bridge

The Akashi Kaikyo Bridge (also called the Pearl Bridge), has the longest central span of any suspension bridge in the world, at 1991 meters. Located in Japan, and completed in 1998, it connects the city of Kobe with Iwaja on Awaji Island by crossing the busy Akashi Strait. The ASTER image was acquired December 8, 2009, covers an area of 15 by 18 km, and is located at 34.6 degrees north latitude, 135 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Disaster Management from Space

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Floods are usually accompanied by cloudy skies making it difficult to monitor them from space. Using radar technology, the new GMES Sentinel-1 satellite is able to 'see' through clouds and rainfall to map emergency-stricken regions.

Video credit: ESA/DLR

Shark Bay, Australia

Hamelin Pool Marine Nature Reserve is located in the Shark Bay World Heritage Site in Western Australia. It is one of the very few places in the world where living stromatolites can be found. These are the first living examples of structures built by cyanobacteria. These bacteria are direct descendants of the oldest form of photosynthetic life on earth, dating back 3,500 million years (Wikipedia). The image was acquired December 30, 2010, covers an area of 34 x 46 km, and is located at 26.4 degrees south latitude, 114.1 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Japan Earthquake Sensed by GOCE

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New studies have revealed that the massive earthquake that hit Japan on 11 March 2011 was also felt in space by ESA’s GOCE satellite. The massive earthquake sent ripples of sound – called infrasound – upwards through the atmosphere. These sound waves caused changes in air density that were detected by ESA’s GOCE gravity satellite as it crossed the wavefront.

Read full article: GOCE the First Seismometer in Orbit.

Video credit: ESA/IRAP/CNES/TU Delft/HTG/Planetary Visions

Japanese Earthquake Sensed from Space

The animation shows how the massive earthquake that hit Japan in 2011 caused ripples in the atmosphere. As sound waves from the earthquake traveled upwards, they caused changes in air density that were detected by ESA’s GOCE gravity satellite as it crossed the wavefront.

Video credit: ESA/IRAP/CNES/TU Delft/HTG/Planetary Visions

SMOS Reveals Thin Sea Ice

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Sea-ice thickness measured by SMOS in the Arctic and Antarctic. Arctic sea ice is significantly thinner in February 2012 than in February 2011. This year, the Arctic experienced a record low of sea-ice extent since satellite measurements began in the 1970s.

Video credit: Planetary Visions

Wasco, California

Wasco, California advertises itself as the "Rose Capital of the World," producing 55% of the rose bushes sold in the United States. Located in the central San Joaquin Valley, Wasco attracted rose producers in the 1960s, when southern California fields were sold for housing developments. Today, over 8000 acres are devoted to cultivation of existing and new varieties of roses, shipped to every state in the US and all over the world. The image covers an area of 10.4 x 15.8 km, was acquired July 10, 2011, and is located near 35.6 degrees north latitude, 119.3 degrees west longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Plosky Tolbachik Volcano Eruption

For the first time in 35 years, the Plosky Tolbachik volcano in Russia's far eastern Kamchatka Peninsula erupted on November 27, 2012, sending clouds of ash to the height of more than 9,800 feet (3,000 meters). In this daytime image acquired February 14, 2013, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft, the snowy winter landscape reveals the still-active lava flows.

A combination of the ASTER thermal infrared channels from the two images acquired during the day and also the previous night highlights the hot rocks in red colors. Steam and ash clouds rising to the north and northeast hide part of the flows, though the thermal infrared channels penetrate the thinner clouds. The image covers an area of 16.7 by 17.8 miles (27 by 28.6 kilometers) and is located at 55.7 degrees north latitude, 160.2 degrees east longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Balearic Islands

Majorca, Mallorca and Ibiza as seen from the ISS by ESA astronaut André Kuipers during his mission to the orbital outpost, PromISSe.

Photo credit: ESA/NASA

Volgograd at Night

The distinctive horseshoe shape of Volgograd by night, as seen by ESA astronaut André Kuipers from his position on the ISS. Andre is [was] onboard the ISS as part of ESA's long duration mission, PromISSe.

Photo credit: ESA/NASA

Monthly Sea Ice Volume

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Time-series of monthly Arctic sea ice volume from CryoSat (red circles) and from PIOMAS (solid line) for two winter growth periods (October – April).

The new CryoSat data provide further evidence of the long-term decreases in Arctic sea ice volume simulated by the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS), which estimates the volume of Arctic sea ice using data from submarine, mooring and satellite observations. However, the rate of decline in autumn ice volume measured by CryoSat is 60% higher than the decline in PIOMAS analyses, but 25% lower in winter.

Video credit: CPOM/UCL/ESA/UW-APL/NSIDC/Planetary Visions

Note: For more information, see Study Sheds New Light on Arctic Sea Ice Volume Losses.

Freshwater Losses in the Middle East

Variations in total water storage from normal, in millimeters, in the Tigris and Euphrates river basins, as measured by NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, from January 2003 through December 2009. Reds represent drier conditions, while blues represent wetter conditions. The majority of the water lost was due to reductions in groundwater caused by human activities. By periodically measuring gravity regionally, GRACE tells scientists how much water storage changes over time.

Image credit: NASA/UC Irvine/NCAR

Note: For more information, see NASA Satellites Find Freshwater Losses in Middle East.

African Equatorial Forest

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The animation shows the change in vegetation in African equatorial forest from 12 months of data from Spot’s Vegetation instrument. The area includes Congo, DR of Congo, Gabon, Equatorial Guinea and Cameroon.

Video credit: CNES/VITO

Note: For some reason, the Venice Land Subsidence video sometimes appears in place of the proper video. Click on the title to see the individual post, and the appropriate video should then appear.

The Bushveld Igneous Complex

The Bushveld Igneous Complex (BIC) is a large layered igneous intrusion within the earth's crust, exposed at the edge of the Transvaal Basin in South Africa. The complex contains the world's largest reserves of the platinum group metals, platinum, palladium, osmium, indium, rhodium and rhenium, along with vast quantities of iron, tin, chromium, titanium and vanadium. Numerous mines, tailings piles, and leach ponds are shown in blue in the ASTER image. The image was acquired October 24, 2006, covers an area of 38 by 52 km, and is located at 25.6 degrees south latitude, 27.4 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Antarctic Ozone Holes: 2011 and 2012

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Ozone distribution over the South Pole from July to December during the years 2011 (left) and 2012 (right).

The 2012 ozone hole duration, geographical extension and depth was much smaller than that of 2011. Ozone loss over the South Pole is displayed at the bottom (the bold dark line indicates the ozone loss for 2012 and the grey line for 2011). The ozone maps were generated by the assimilation of GOME-2 total ozone data into the model TM3DAM. GOME-2 is carried by Eumetsat’s MetOp mission.

Video credit: KNMI

Venice Land Subsidence

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Venice has been subject to floodings for hundreds of years and the problem is increasing due to sea level rise and a constant subsidence of the city.

Radar data - like it will be delivered from the first GMES satellite - are providing the means for a continuous monitoring of ground movement with an accuracy of a few millimeters per year.

Video credit: ESA/DLR

3D View of Siding Spring Observatory Wildfire

In mid-January, 2013, a massive wildfire damaged Australia's largest optical astronomy facility, the Siding Spring Observatory, causing significant damage. All of the workers were safely evacuated, but five buildings, including a visitors' center and lodge, were badly damaged. The facility remains closed while the extent of damage is assessed. Australia has suffered both its hottest summer on record, and a devastating wildfire season. This was one of numerous large fires that have devastated the country.

This 3-D perspective view image was created from data acquired February 4, 2013, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft. The image is located near 31.2 degrees south latitude, 149 degrees east longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Scandinavian Snows

In this image from the Envisat satellite, clouds cover the North Sea and sweep down to the strait between Denmark (lower-right corner) and Norway (upper-center). In the upper-right corner, a thicker blanket of clouds covers south eastern Norway and spreads into Sweden. Located on the Scandinavian Peninsula, Norway is Europe’s northernmost country and is famed for its fjords. Some of these are visible in the image as dark lines between the white and snow-covered land. Near the top of the image, we can see part of Norway’s longest and deepest fjord, the Sognefjord. In the lower-right corner, we can see part of Denmark’s Jutland peninsula, with small and large bodies of water speckling the flat terrain.

Text credit: ESA;Video credit: ESA

Note: The image shown in this video can be found here; unfortunately, at 13.42 MB, it is too large for Blogger to upload.

Jakarta, Indonesia

Jakarta is the capital and largest city of Indonesia. The population of the Jakarta conurbation is over 28 million, making it perhaps the largest metropolitan area in the world in terms of inhabitants. Established in the 4th century, it became an important trading port for the Kingdom of Sunda, and was the capital of the Dutch East Indies under the name of Batavia. The rapid growth of the city is illustrated in the three satellite images. In 1972, Landsat MSS captured an image of the city with about 11 million inhabitants. By 1994, the Landsat Thematic Mapper saw a city of 19 million. And in 2006, ASTER imaged a city of 25 million inhabitants. Each image covers an area of 40 by 50 km, and is located at 6.1 degrees south latitude, 106.8 degrees east longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Note: A rare error on the part of NASA here: They claim that the Jakarta conurbation is "perhaps the largest metropolitan area in the world in terms of inhabitants," with 28 million persons. However, the Tokyo metro area is far larger, with over 35.6 million inhabitants.

NASA to Launch Ocean Wind Monitor to Space Station

Artist's rendering of NASA's ISS-RapidScat instrument (inset), which will launch to the International Space Station in 2014 to measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. It will be installed on the end of the station's Columbus laboratory.

Illustration credit: NASA/JPL-Caltech/JSC

Note: For more information, see NASA to Launch Ocean Wind Monitor to Space Station; also, QuikScat's Eye on Ocean Winds Lives On with RapidScat and NASA's RapidScat to Unveil Hidden Cycles of Sea Winds.

Arctic Sea Ice: 1978-2010

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Time series of Arctic sea ice concentration in September from 1978 to 2010.

Video credit: ESA/DLR

Cloudless British Isles

The lush landscapes of Ireland, Great Britain and northern France are pictured in this rare cloud-free view, acquired by Envisat on 28 March 2012.

To the west, thousands of lakes speckle the island of Ireland. Brown rugged cliffs along the coast frame its plush green interior. In the lower-right corner, the river Seine flows through Paris (seen here as a gray area) and snakes toward the English Channel. Following mainland Europe’s coastline north, we can see the Rhine–Meuse–Scheldt delta followed by part of the intertidal Wadden Sea in the extreme top-right corner. The green and tan-tinted swirls in the seas and channels are due to sediments being transported in the water. Sediment is particularly concentrated around Britain’s southeastern coast, carried by the River Thames through London and into the North Sea.

This image is featured on the Earth from Space video program.

Photo credit: ESA

Jebel Uweinat

Jebel Uweinat (1,934 meters, mountain of sourcelets) is a mountain range in the area of the Egyptian-Sudanese-Libyan border. In general, the west slope constitutes an oasis, with wells, bushes and grass. The area is notable for its prehistoric petroglyphs. Engraved in sandstone, petroglyphs of Bushmen style are visible, representing giraffes, lions, ostriches, gazelles, and human figures. The western part of the massive consists of intrusive granite, arranged in a ring shape of some 25 km diameter. Its eastern part consists of sandstone; four plateaus emerge from the level of the surrounding desert. One of the driest places on earth, it reportedly hasn't rained since 1998 (Wikipedia). The image was acquired March 17, 2012, covers an area of 40 x 43 km, and is located at 22 degrees north latitude, 24.9 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Altimeter Readings over Cuba

CryoSat altimeter view of sea level and topography over the Caribbean Sea and Cuba. The image shows radar reflections that differ in intensity between the water and elevated land. Near the edges of the island, points of high radar reflections are pictured in red. This is due to the higher reflectiveness of calm waters of the bay and over coral reefs.

Image credit: ESA

Kangerdlugssuaq Glacier, Greenland

The Kangerdlugssuaq glacier and its ice stream are pictured in this week’s image, acquired on 19 September 2012 by Landsat-7. It is the largest outlet glacier on Greenland’s east coast, discharging ice into the surrounding oceans. In this image we can see hundreds of icebergs speckling the water. A recent study based on satellite observations revealed that over the past 20 years the ice melting in Greenland and Antarctica has contributed about 11 mm to the global sea-level rise. This image clearly shows the glacier’s calving front, where ice breaks away. Over the years, satellite images have shown that this front has retreated – an indication that the glacier is getting smaller over time.

This image is featured on the Earth from Space video program.

Photo credit: USGS/ESA

Po River, Italy

This image is a compilation of three radar images from the Japanese ALOS satellite and shows the Po River, which flows over 650 km from west to east across northern Italy as the country’s longest river. Agriculture is one of the main economic uses of the Po Basin because of the fertile soils, and this image clearly shows a landscape dominated by fields. Branching off of the river in the center of the image and snaking through the landscape to the lower-right corner is the Po di Goro, one of the main channels of the Po Delta. The section of the main river pictured and the Po di Goro form the border of the Italy’s Veneto (north) and Emilia–Romagna (south) regions.

This image is featured on the Earth from Space video program.

Image credit: JAXA/ESA

Concordia Base, Antarctica

The Proba-1 microsatellite's High Resolution Camera images the French-Italian Concordia base in the Antarctic interior. The image has 5-m spatial resolution and covers approximately 25 sq km. It was acquired on 24 November 2012.

Photo credit: ESA

Gulf of Guinea

This Envisat image shows West Africa around the Gulf of Guinea, with parts of Nigeria to the north and Cameroon to the east visible. Cameroon’s largest city of Douala is located near the Wouri estuary near the center of the image. North of the Wouri estuary, the Mount Cameroon volcano is clearly visible. The island of Bioko is pictured just off the coast.

Reflections of Envisat’s radar signal appear like specks of white throughout the image. They are particularly concentrated around cities such as Malabo on the island, Douala near the Wouri estuary and the populated areas of southern Nigeria. These white specks are the typical appearance of built-up areas in radar images, owing to the multiple reflection of the radar beam by buildings and especially metal constructions.

This image is a compilation of three images from Envisat’s radar, acquired on 6 February, 7 March and 6 April 2012 – just two days before communication with the satellite was lost.

Image credit: ESA

Santorini Rising

Model of vertical movement across Santorini from January 2011 to present, derived from data from the Envisat and TerraSAR-X missions. Over the past year and a half, parts of Santorini have risen by 14 cm, such as the Kameni islands in the center. Scientists believe that new molten rock has been squeezing up beneath the volcano at a depth of about 4 km, pictured here as a red dot.

Image credit: M. Parks

Chernozem Cropland

This ALOS satellite image shows an area with extensive agricultural use in western Russia, with roads and rivers cutting through the cropland. This area, part of Russia’s Black Earth Region, is about 400 km directly south of Moscow. Many grains are grown here, such as winter wheat and rye.

This image is a compilation of three passes by the Japanese Advanced Land Observation Satellite’s radar on 14 June 2009, 14 September 2009 and 2 August 2010. Each image at the different recording date is assigned a color (red, green or blue) and combined to produce this representation. The colors reveal changes in the surface between the satellite’s passes.

Photo credit: JAXA, ESA

Drought in Kansas: 2012 vs 2002

As the U.S. Midwest continues to suffer from near-historic drought conditions, farmers in southwestern Kansas are among the hardest hit. According to the U.S. Department of Agriculture, the area is under "exceptional drought" conditions. This has led to significant reductions of the corn, soybean and pea crops. The two satellite images shown here, obtained about 10 years apart, clearly illustrate the effects of the drought. The top half of this image was acquired on September 6, 2012 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft; the bottom half of the image was acquired by the Landsat Thematic Mapper on September 15, 2002. Vegetation appears in red, and bare fields are gray or greenish in color. Both images cover an area of 9.3 by 27.9 miles (15 by 44.5 kilometers) and are located near 38.2 degrees north latitude, 100.8 degrees west longitude.

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Arctic Ocean Ice Decrease, 1979-2010

This animation shows Arctic ice cover from 1978 to 2010. The past five years have seen the lowest Arctic sea-ice extent since satellite measurements began in the 1970s.

Video credit: ESA/DLR

Meteor Smoke and Noctilucent Clouds

Anyone who's ever seen a noctilucent cloud or “NLC” would agree: They look alien. The electric-blue ripples and pale tendrils of NLCs reaching across the night sky resemble something from another world.

Researchers say that's not far off. A key ingredient for the mysterious clouds comes from outer space.

"We've detected bits of 'meteor smoke' embedded in noctilucent clouds," reports James Russell of Hampton University, principal investigator of NASA's AIM mission to study the phenomenon. "This discovery supports the theory that meteor dust is the nucleating agent around which NLCs form."

Noctilucent clouds are a mystery dating back to the late 19th century. Northern sky watchers first noticed them in 1885 about two years after the eruption of Krakatoa. Ash from the Indonesian volcano caused such splendid sunsets that evening sky watching became a worldwide pastime. One observer in particular, a German named T.W. Backhouse who is often credited with the discovery of NLCs, noticed something odd. He stayed outside longer than most people, long enough for the twilight to fully darken, and on some nights he saw wispy filaments glowing electric blue against the black sky. Scientists of the day figured they were some manifestation of volcanic dust.

Eventually Krakatoa’s ash settled and the sunsets faded, but strangely the noctilucent clouds didn’t go away. They’re still present today, stronger than ever. Researchers aren’t sure what role Krakatoa’s ash played in those early sightings. One thing is clear, however: The dust behind the clouds we see now is space dust.

Mark Hervig of the company GATS, Inc, led the team that found the extraterrestrial connection.

"Using AIM's Solar Occultation for Ice Experiment (SOFIE), we found that about 3% of each ice crystal in a noctilucent cloud is meteoritic," says Hervig.

The inner solar system is littered with meteoroids of all shapes and sizes--from asteroid-sized chunks of rock to microscopic specks of dust. Every day Earth scoops up tons of the material, mostly the small stuff. When meteoroids hit our atmosphere and burn up, they leave behind a haze of tiny particles suspended 70 km to 100 km above Earth's surface.

It's no coincidence that NLCs form 83 km high, squarely inside the meteor smoke zone.

Specks of meteor smoke act as gathering points where water molecules can assemble themselves into ice crystals. The process is called "nucleation."

Nucleation happens all the time in the lower atmosphere. In ordinary clouds, airborne specks of dust and even living microbes can serve as nucleation sites. Tiny ice crystals, drops of water, and snowflakes grow around these particles, falling to Earth if and when they become heavy enough.

Nucleating agents are especially important in the ethereal realm of NLCs. The clouds form at the edge of space where the air pressure is little more than vacuum. The odds of two water molecules meeting is slim, and of sticking together slimmer still.

Meteor smoke helps beat the odds. According AIM data, ice crystals can grow around meteoritic dust to sizes ranging from 20 to 70 nanometers. For comparison, cirrus clouds in the lower atmosphere where water is abundant contain crystals 10 to 100 times larger.

The small size of the ice crystals explains the clouds' blue color. Small particles tend to scatter short wavelengths of light (blue) more strongly than long wavelengths (red). So when a beam of sunlight hits an NLC, blue is the color that gets scattered down to Earth.

Meteor smoke explains much about NLCs, but a key mystery remains: Why are the clouds brightening and spreading?

In the 19th century, NLCs were confined to high latitudes—places like Canada and Scandinavia. In recent times, however, they have been spotted as far south as Colorado, Utah and Nebraska. The reason, Russell believes, is climate change. One of the greenhouse gases that has become more abundant in Earth's atmosphere since the 19th century is methane. It comes from landfills, natural gas and petroleum systems, agricultural activities, and coal mining.

It turns out that methane boosts NLCs.

Russell explains: "When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor. This extra water vapor is then available to grow ice crystals for NLCs."

If this idea is correct, noctilucent clouds are a sort of "canary in a coal mine" for one of the most important greenhouse gases.

And that, says Russell, is a great reason to study them. "Noctilucent clouds might look alien, but they're telling us something very important about our own planet."

Photo credit: NASA; video credit: NASA

Earth

MSG-3 first image of Earth, acquired on 7 August 2012 by its Spinning Enhanced Visible and Infrared Imager (SEVIRI).

Photo credit: Eumetsat

London

Preparations for London's 2012 Summer Olympic Games began years before July 27th's opening ceremonies. The Games use a mixture of new venues, existing and historical facilities, and temporary facilities. Major construction projects included the new 400-acre Olympic Park, constructed on a former industrial site in the east of London.

This simulated natural color image of London was acquired May 26, 2012, by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft. It covers an area measuring 9.3 by 9.3 miles (15 by 15 kilometers), and is centered at 51.5 degrees North Latitude, 0.1 degree west longitude. The Olympic Park is visible in the upper right of the image.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Deforestation of the Amazon Rain Forest

This animation shows deforestation of the Amazon Rainforest in the western Brazilian state of Rondônia from 1986 to 2010. While the central area remains green and untouched, squares of light green and brown pop up over time as the forest is cut away.

The animation was created using two cloud-free images: the first from NASA’s Landsat mission in 1986, and the second from the Spanish Deimos mission in 2010. The changes over time were simulated by referring to other satellite data acquired during the 24 years between the two images.

Video credit: ESA/USGS/Deimos Imaging; text credit: ESA/USGS/Deimos Imaging

Petermann Glacier

The Petermann Glacier grinds and slides toward the sea along the northwestern coast of Greenland, terminating in a giant floating ice tongue. Like other glaciers that end in the ocean, Petermann periodically calves icebergs. A massive iceberg, or ice island, broke off of the Petermann Glacier in 2010. Now, nearly two years later, another chunk of ice has broken free.

The Moderate Resolution Imaging Spectroradiometer, or MODIS, on NASA’s Aqua satellite observed the new iceberg calving and drifting downstream on July 16–17, 2012. Because Aqua is a polar-orbiting satellite, it makes multiple passes over the polar regions each day.

Photo credit: NASA

Camargue Delta, France

This image from ALOS shows southern France and the divide of the Rhone River: the 'Grand Rhône' flows down the center of the image while the 'Petit Rhône' is visible to the west. This divide at the French city of Arles forms the Camargue delta region. In the upper right corner of the image, we can see the Alpilles mountains. The green area south of the mountains is a large nature reserve.

This image is a compilation of three radar passes on 14 May 2008, 20 May 2010 and 5 July 2010. Each is assigned a color (red, green or blue) and combined to produce this representation. The colors reveal changes in the surface between the satellite’s passes.

Photo credit: JAXA, ESA

The Wadi As-Sirhan Basin

Tapping into fossil ground water, Saudi Arabia has been steadily developing agricultural fields using center pivot irrigation. A remarkable example is in the Wadi As-Sirhan Basin in northwest Saudi Arabia. In the 1984 Landsat image (top), no fields are yet present. By 2000, ASTER showed extensive farming activity (middle); vegetation is bright red. And by 2011, the ASTER image shows several areas where wall-to-wall fields were developed, each about 1 km in diameter (bottom). The images cover an area of 19.5 x 33 km, and are located at 30.5 degrees north latitude, 38 degrees east longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Dawson, Canada

Dawson, Canada was a boom town in 1898, with a population of 40,000. Discovery of gold in the Klondike fueled the massive influx of miners, merchants, and other support professions to this town on the Yukon River. The current population is just over 1,000, with over 60,000 tourists invading the town each summer. Shortly after gold discovery, large gold dredges began an industrial mining operation, leaving large tailings piles in their wake. These can be clearly seen along the creek east of Dawson. The image was acquired September 19, 2010, and is located at 64.1 degrees north latitude, 136.4 degrees west longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

The Waldo Canyon Fire

The Waldo Canyon Fire, west of Colorado Springs, Colo., is being called the worst fire in Colorado history. Since its onset on June 23, 2012, the fire has consumed more than 18,000 acres and hundreds of homes. Containment of the fire is expected by July 6. In this image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft on July 4, healthy vegetation is red, water is dark blue, streets and buildings are gray, and the burned areas are black. The image covers an area of 9.3 by 12.1 miles (15 by 18 kilometers) and is located at 36.9 degrees north latitude, 104.9 degrees west longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Mont Saint Michel

This image acquired on 3 May 2012 from the Pleiades satellite shows the island of Mont Saint Michel and its surrounding bay in northwest France. Mont Saint Michel was a tidal island, meaning that it was surrounded by water at high tide and only when the waters receded was it reachable by foot. In the late 1800s, the causeway was raised to make it accessible from the mainland at all times. In this image, we can clearly see where the water meets the mud flats, with multiple channels weaving through the mud.

Photo credit: CNES 2012/Astrium Services/Spot Image

Atacama Desert

The southern Atacama Desert is pictured in this Envisat image, with the border of Chile (west) and Argentina (east) running down the middle. The Atacama is believed to be the driest desert in the world, and the lack of cloud cover in this image highlights the dry climate.

This image was acquired by Envisat’s MERIS instrument on 4 March 2012.

Photo credit: ESA

Note: The Atacama desert is where the various telescopes for the European Southern Observatory are located; it is also where scenes for the James Bond movie, Quantum of Solace, were filmed.

New Estimate of Gross Carbon Emissions From Tropical Deforestation

Distribution of annual carbon emissions from gross forest cover loss between 2000 and 2005 mapped at a spatial resolution of 11.5 miles (18.5 kilometers).

Image credit: Winrock International

Note: For more information, see Study Slashes Deforestation Carbon Emission Estimate.

Picher, Oklahoma

Picher, Oklahoma once boasted 20,000 people in this mining town in northeast Oklahoma. Now, after a 2009 tornado, and a federal cleanup program, the town is a modern-day ghost town. Picher lies in the middle of the Tar Creek Superfund site, an expanse of lead- and zinc-mining towns that extends into Missouri and Kansas. But mine cave-ins, sinkholes, and a creek that flows orange from pollution have forced abandonment of Picher and the surrounding smaller towns. The image was acquired July 12, 2006, covers an area of 17.7 by 16.8 km, and is located at 37 degrees north latitude, 94.8 degrees west longitude.

Photo credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Lake Garda, Italy

Italy’s Lake Garda and the city of Verona south of the Italian Alps are pictured in this image from ALOS observation satellite. With an area of 370 sq km, Garda is the largest lake in Italy and the third largest in the Alpine region. East of the lake is the Adige River, flowing south before curving east toward Verona. The city of Verona has been awarded World Heritage Site status by UNESCO because of its urban structure and architecture – among them the circular Roman amphitheater, visible when zooming in.

Photo credit: JAXA/ESA

NASA's Aquarius Maps Ocean Salinity Structure

New research using salinity data from NASA's Aquarius instrument on the Aquarius/SAC-D observatory has given scientists an unprecedented look at a key factor involved in the formation of an oceanic wave feature in the tropical Pacific and Atlantic Oceans that influences global climate patterns.

Tropical instability waves are westward-traveling waves that form along the interface between areas of cold and warm sea surface temperatures near the equator. Existing studies suggest that these waves can have wavelengths of 1,000-2,000 kilometers and have an average period between waves of about one month. These waves redistribute various properties of seawater within the ocean, including temperature, salinity, nutrients, and carbon. They interact with ocean currents, affect large-scale climate patterns such as El Niño and La Niña, and influence marine ecosystems and the carbon cycle.

Previous observations of tropical instability waves have been limited to satellite observations of sea surface temperature, sea level, ocean surface wind, and ocean surface chlorophyll abundance, as well as sparse direct ocean measurements. Salinity has been found to play an important role in the physics of these waves, and observations of their salinity are important to understanding them and their impacts on climate variability and prediction, and biogeochemistry. However, until now salinity observations of them have been limited to very sparse direct ocean measurements. Aquarius provides an unprecedented opportunity to observe their salinity.

In a study in press in the journal Geophysical Research Letters, a team led by Tong Lee of NASA's Jet Propulsion Laboratory, Pasadena, California, and including scientists from Earth & Space Research in Seattle, Aquarius data were used to reveal the salinity structure associated with tropical instability waves in the Pacific Ocean. The figure shows sea surface salinity (color shading in panels a and b) on December 18, 2011, derived from Aquarius measurements, showing the peaks and valleys of tropical instability waves in the eastern to central equatorial Pacific Ocean. The salinity structure is coherent with those obtained from other satellite derived products such as sea surface temperature (contour lines in panel a) and ocean surface currents (arrows in panel b). The unit for the sea surface salinity (SSS) is parts per thousand (the Practical Salinity Unit or PSU). The unit for sea surface temperature (SST) is degree centigrade.

The team found that Aquarius' salinity observations showed a clear signature of the waves near the equator in the Pacific Ocean where large contrasts in salinity occur between the saltier waters of the South Pacific and fresher waters of the North Pacific. The Aquarius data reveal that the waves move much faster at the equator than they do away from the equator, a feature that had not previously been well documented.

Aquarius observations show that near the equator, the waves have a dominant period of approximately 17 days. Aquarius' ability to reveal oceanic features on such short timescales was unexpected, as the mission was designed to study salinity changes on time scales of a month and longer. Salinity variability associated with tropical instability waves is larger near the equator, while sea surface temperature and sea level variability associated with the waves is larger a few degrees away from the equator. Salinity observations from Aquarius can therefore fill an important gap in studying tropical instability waves by providing measurements that are complementary to other satellite observations and direct ocean measurements.

Reference: Lee, T.; G. Lagerloef; M. Gierach; H.-Y. Kao; S. Yueh; and K. Dohan, 2012: "Aquarius reveals salinity structure of tropical instability waves," Geophysical Research Letters, in press.

Image credit: NASA/JPL-Caltech/GSFC

The Paraná River

The Paraná River cuts through this image of southern Brazil, acquired by the MERIS instrument on Envisat on 19 March. In the area pictured, the river marks the borders of the Brazilian states of Mato Grosso do Sul to the north and west, São Paulo to the east and Paraná to the south.

Agricultural structures are evident in the surrounding land. Near the center of the image, smoke from a fire was captured blowing southwest from its source.

Photo credit: ESA

A Crack on Pine Island Glacier

This Envisat image shows the Pine Island Glacier in West Antarctica and reveals a crack in the glacier’s tongue about 25 km long. The image was acquired by Envisat’s radar on 6 April 2012, just two days before contact with the satellite was lost.

Photo credit: ESA

Eruption Plume from Sheveluch Volcano

On the night of June 2, 2012, a large eruption plume from eastern Russia's Sheveluch volcano was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft. Sheveluch is one of the most active volcanoes on the Kamchatka peninsula, with frequent explosive events that can disrupt air traffic over the northern Pacific. In this color composite of three thermal infrared channels, the ash component of the plume is depicted in red, the water droplets and ice are in blue, and the sulfur dioxide (SO2) component is in yellow. The image is centered near 56.6 degrees north latitude, 161.4 degrees east longitude, and covers an area of 37 by 74 miles (60 by 120 kilometers).

Image credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Copenhagen, Denmark

Copenhagen, the capital of Denmark, is highlighted in this image. The largest city in Denmark, Copenhagen is located on the eastern side of the island of Zealand (left) and on the island of Amager (right). The island visible east of Amager is Saltholm, translated as ‘Salt Islet’. The white structure southwest of Saltholm is the artificial island of Peberholm, translated as ‘Pepper Islet’. Peberholm was created as part of the Øresund Bridge, a combined two-track rail and four-lane road bridge-tunnel across the Øresund Strait that connects Copenhagen with the Swedish city of Malmö (not visible). Peberholm serves as a crossover point between the bridge, completed in 2000, and the 4050-m long Drogden Tunnel. Copenhagen Airport is visible as an L-shaped, white structure on the eastern side of Amager.

Photo credit: CNES, Spot Image