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