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The Garabogazkol June 14, 2006

Posted by jtintle in Earth, Moderate Resolution Imaging Spectroradiometer, Planets, Satellite, Space Fotos, Terra satellite.
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The Garabogazkol

Credit:

Jeff Schmaltz, MODIS Land Rapid Response Team,
NASA GSFC

Description:

This MODIS Terra image, acquired June 12, 2006, shows the Garabogazkol (also known asthe Kara-Bogaz-Gol) – a shallow depression in the northwestern corner of Turkmenistan. Separated from the Caspian Sea by a thin sandbar, its water volume fluctuates seasonally. At times it becomes a large bay of the Caspian Sea, while at other times its water level drops drastically.

The water is very salty, much more so than the Caspian Sea, and has almost no marine life vegetation! The salt has been both good and bad – the valuable salts have been harvested from the 1950s on. But the salt has also caused health problems and poisoned soil for hundreds of kilometers downwind to the east.

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Ocean Vortex off Western Australia June 11, 2006

Posted by jtintle in Aqua, Australia, Earth, Moderate Resolution Imaging Spectroradiometer, NASA, Planets, Satellite, Space Agencies, Space Fotos.
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Ocean Vortex off Western Australia

Credit:

Norman Kuring, Ocean Color Group, NASA

Descrition:

Scientists recently discovered a huge spinning vortex in the Indian Ocean off the coast of Western Australia near Perth. The circling current is sweeping fish larvae and coastal plants out to sea, says Anya Waite, the biological oceanographer from the University of Western Australia who led the team. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite detected the vortex on June 5, 2006, by the high concentrations of chlorophyll from coastal plankton (tiny plants) in the water. In the top image, the high chlorophyll concentrations are yellow against an aquamarine background of lower concentrations. The vortex creates a yellow loop around a blue and yellow oval center where chlorophyll concentrations are lower. The vortex measured about 200 kilometers across and 1,000 meters deep, reported the team that discovered it. The circular current was spinning at 5 kilometers per hour (3 miles per hour).

The vortex is an offshoot of the Leeuwin Current, a river of warm water that sweeps south along the coast of Western Australia. The warm current is visible in the lower sea surface temperature image, also taken by MODIS on June 5, as a warm pink streak against the cooler purple of the surrounding ocean. The vortex forms a pink oval. Below the vortex, where water temperatures drop with the change in latitude, the warm current is especially clear.

In general, loops and eddies in the Leeuwin Current, such as the one that formed the vortex, are common. Like other eddies, the vortex could have a mixed impact on the ecosystem. “Essentially, the eddy could either be a death trap for larval fish, or a nursery for them,” says Waite. “For most finfish larvae, offshore transport away from their adult habitat is probably detrimental. But it’s possible that long-lived rock lobster larvae can benefit from the enhanced offshore productivity in eddies, increasing their survival rate in the open ocean.”

The Leeuwin Current is unlike the currents that run along the west coasts of Southern Africa and South America, the other large land masses at this latitude. In the Atlantic and Pacific Oceans, strong currents from the Southern Ocean carry cold water along the west coasts of Africa and South America. The cold current allows water from the ocean floor to rush to the surface, carrying iron and other nutrients. These nutrients nourish the phytoplankton (ocean plants) that form the base of the marine food chain. As a result, the coastal waters of Chile and southern Africa are productive fisheries, teaming with life. The Leeuwin Current, on the other hand, is warm and keeps denser cool water from welling up. As a result, the waters off Western Australia are relatively poor in nutrients and can’t support the same type of ecosystems as South America and Africa. The warm waters do allow tropical plants and animals to survive much farther south than they might otherwise.

Phytoplankton Blooms in the Black Sea June 1, 2006

Posted by jtintle in Aqua, Earth, Goddard Space Flight Center, Moderate Resolution Imaging Spectroradiometer, NASA, People, Planets, Satellite, Space Agencies, Space Fotos.
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Phytoplankton Blooms in the Black Sea
Resolutions: 1km (381.2 KB)
500m (1003.1 KB)
250m (3 MB)

Credits:

Jesse Allen, Earth Observatory

Descriptions: 

This image of the Black Sea, acquired on May 30, 2006, by the MODIS on the Aqua satellite, shows swirling blooms of phytoplankton coloring the surface waters blue and green. The large volume of freshwater flowing into the Black Sea from large European rivers, including the Danube and Dnieper Rivers, makes the sea much less salty than open oceans. The freshwater flow also delivers many nutrients, which are washed into the sea from land. These nutrients support large blooms of phytoplankton: microscopic photosynthetic organisms (algae and bacteria). The chlorophyll and other pigments the organisms use for photosynthesis change the way light reflects off the surface, and these changes are visible in satellite imagery.

Gilbert Islands, central Pacific Ocean May 14, 2006

Posted by jtintle in Earth, Gilbert Islands, Moderate Resolution Imaging Spectroradiometer, Planets, Space Fotos, Terra satellite.
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Gilbert Islands, central Pacific Ocean
Credit: Jeff Schmaltz
Links: MODIS Land Rapid Response Team,
NASA GSFC

This image, acquired by the MODIS on the Terra satellite, shows the Gilbert Islands, located in the central Pacific Ocean. The Gilbert Islands are a chain of 16 atolls and coral islands, and are one of the island groups that form the Republic of Kiribati. The islands are about 930 miles north of Fiji, and the equator runs through the center of the islands, right through the center of the image.

The islands were discovered by Europeans in the late 18th century; one of the explorers was Captain Thomas Gilbert.

The native population of the Gilberts are Micronesian, similar in many respects to the Marshall Islands, the Carolines, and the Marianas.

Fires along the Border of Mongolia and Russia May 3, 2006

Posted by jtintle in Aqua, Earth, Moderate Resolution Imaging Spectroradiometer, NASA, Space Fotos.
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Fires along the Border of Mongolia and Russia Click here to view full image (1333 kb)

Large fires were burning at the border of Russia and Mongolia on May 1, 2006, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite passed over the region. The actively burning portions of the fires are outlined in red, and plumes of thick, brownish-gray smoke blow southeast. Dark, almost charcoal-colored burn scars are spread across the landscape. At upper left, snow still covers mountain peaks despite the arrival of spring more than a month before.

NASA image created by Jesse Allen, Earth Observatory, using data obtained from the Goddard Earth Sciences DAAC.


Princess Astrid Ice Shelf December 15, 2005

Posted by jtintle in Earth Observing System (EOS), Antarctica, Aqua, Earth, Moderate Resolution Imaging Spectroradiometer, NASA, National Snow and Ice Data Center, Space Fotos, Terra satellite.
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Princess Astrid Ice Shelf Click here to view full image (77 kb)

Released in the fall of 2005, the MODIS Mosaic of Antarctica (MOA) has offered a new view of the frozen continent with unprecedented detail. The map is compiled from 260 images of Antarctica acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA’s Terra and Aqua satellites. Using images collected between November 20, 2003, and February 29, 2004, MOA includes all land areas covered by the Antarctic Treaty. This MOA image shows part of the Princess Astrid Ice Shelf. Prominent on this ice shelf are features that glaciologists often study in Antarctica: blue ice and melt ponds.

Snow is composed of tiny ice crystals with many facets that reflect light like a mirror. Light shining into snow is bounced back largely unaltered, so snow appears white. Over time, however, compressed layers of snow turn to ice, and wind can expose this ice by sweeping away or evaporating lighter layers of snow. Compressed ice has big, clear crystals that allow light to travel through more of the ice before reflecting back. Ice absorbs a tiny amount of red light from the spectrum, so the light coming out of the ice appears blue to human eyes. Although MOA imagery is grayscale, blue ice nevertheless has a unique appearance in the imagery. In this image, windswept blue ice appears as swirling patchwork patterns of dark gray.

Melt ponds also appear in this image, showing up as curving lines of charcoal gray. Melt ponds have attracted the scrutiny of glaciologists because of the effects they have on ice shelves and glaciers. Warm summers can cause ponds of melt water to collect on the ice surface, and these ponds may eventually fill small cracks in the ice. Depending on the depth of a crack and the amount of water filling it, the water may deepen the crack, eventually carving all the way through the thick plate of ice. On a glacier, melt ponds can lead to water flow on the glacier’s underside, loosening it from the bedrock and accelerating flow. On an ice shelf, melt ponds can lead to ice shelf disintegration.

Image courtesy the National Snow and Ice Data Center, based on data from NASA’s Aqua and Terra MODIS sensors.

Hurricane Epsilon December 7, 2005

Posted by jtintle in Earth Observing System (EOS), Earth, Goddard Space Flight Center, Hurricane Epsilon, Moderate Resolution Imaging Spectroradiometer, NASA, Space Fotos, Terra satellite.
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Hurricane Epsilon Click here to view full image (4237 kb)

Explanation:
The official hurricane season in the Atlantic Ocean runs from June 1 to November 30 each year, but on very rare occasions, tropical storms and even hurricanes form outside the season. In 150 years of records, a hurricane has formed outside of the season on only four other occasions. But with so many records broken by the 2005 Atlantic hurricane season, it seems almost unsurprising to find Hurricane Epsilon ushering in December and bumping that out-of-season-hurricane record up to five storms. Epsilon formed in the Central Atlantic about halfway between the Azores Islands and Bermuda on November 29, 2005.

This image shows Hurricane Epsilon in the mid-Atlantic, as observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on December 4, 2005, at 13:30 UTC (10:30 a.m. local time). At that time, the hurricane had peak sustained winds of 140 kilometers per hour (85 miles per hour). That intensity appears to be the strongest the storm will achieve, according to forecasts from early on December 5, 2005. The storm had been sustaining winds from 120-140 kilometers per hour (75-85 mph) for roughly 48 hours at that time. This longevity ensures that Epsilon, despite having four other storms for company in the out-of-season-hurricane neighborhood, will nevertheless go down alone in the record books in at least one respect: it has broken a new record for the longest-lived December hurricane.

Image Credit: Jeff Schmaltz, MODIS Rapid Response Team,Goddard Space Flight Center

Karthala Volcano Erupts December 1, 2005

Posted by jtintle in Earth Observing System (EOS), Earth, Karthala, Moderate Resolution Imaging Spectroradiometer, NASA, Space Fotos, Terra satellite.
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Karthala Volcano Erupts Click here to view full image (298 kb)

On November 24, 2005, Americans celebrated Thanksgiving. Halfway around the world, some 2,000 people fled their homes, hoping to escape the latest eruption of the Karthala Volcano. The volcano covered nearby villages in ash, and locals had little means of protecting their lungs besides covering their faces with scarves. As of November 28, one casualty (an infant) had been reported.

Karthala is one of two volcanoes that make up Grand Comore (or Ngazidja) Island in the Comoros archipelago. These islands lie in the Indian Ocean, between Africa and Madagascar. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard the Terra satellite captured this image on November 25, 2005. In this image, Grand Comore appears only in outline as material from the eruption completely obscures the satellite’s view of the land surface. The volcanic ash ranges in color from tan to beige. It has spread out around the volcano in all directions, but moves primarily eastward.

With an altitude of 2,361 meters (7,746 feet), Karthala is a shield volcano, with smooth slopes built from hardened lava. Comprising the southern portion of Grand Comore Island, Karthala is a regular troublemaker in its neighborhood. The volcano has erupted about 20 times in the last century, most recently in April 2005. The November 2005 eruption caused fears of lava floods and poisonous gases. The volcano had showed signs of trouble for several days before the eruption, and the ground continued to rumble afterwards.

Even after the volcano stopped erupting, trouble for the region was expected to continue. The November eruption fouled drinking water already made scarce by the region’s dry season. According to news reports, the UN Office for the Coordination of Humanitarian Affairs estimated that almost 120,000 people were without clean drinking water after the volcano dropped ash into water cisterns.

NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

Ireland November 30, 2005

Posted by jtintle in Earth Observing System (EOS), Earth, Moderate Resolution Imaging Spectroradiometer, NASA, Space Fotos, Terra satellite.
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Ireland

Satellite: Terra
Date Acquired: 11/21/2005
Resolutions: 1km (238.2 KB)
500m (912.9 KB)
250m (2.4 MB)
Bands Used: 1, 4, 3
Credit: Jeff Schmaltz
MODIS Land Rapid Response Team,
NASA GSFC

Explanation: The rich and vibrant greens in this image depict the aptly-named “Emerald Isle?. Ireland (also called the ‘Republic of Ireland’) comprises about 5/6 of the island, while Northern Ireland, a region of the United Kingdom, encompasses the remaining portion. The darker colors in this image signify the coastal mountain ranges, while the lighter colors indicate the central lowlands or plains. In the past, forests covered the entire island, but the island was virtually stripped of its trees in the 17th century. Since then, agriculture has dominated the landscape, although currently Ireland’s economy is dominated by the industrial and service sectors. Ireland is located at high latitude (between 51.5 and 55.5 degrees North), but its climate is very mild: the average temperature in Winter is about 4 degrees Celsius (39 degrees Fahrenheit), while the average Summer temperature is about 16 degrees Celsius (61 degrees Fahrenheit). This condition is caused by the North Atlantic Current or Drift (of which the Gulf Stream is a part); warm water from the Gulf of Mexico is carried to the North Atlantic by strong ocean currents. Some of the water evaporates, making the water that remains much saltier and colder, and, therefore, more dense. It then sinks towards the ocean floor and is carried back in the direction from which it came. Recent research by NASA and other scientists indicates that this conveyor belt-like system may have been, and continue to be, disrupted by global warming.

The Caspian Sea November 29, 2005

Posted by jtintle in Earth Observing System (EOS), Earth, Moderate Resolution Imaging Spectroradiometer, NASA, Space Fotos, Terra satellite.
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The Caspian Sea

Satellite: Terra
Date Acquired: 11/21/2005
Resolutions: 1km (434.6 KB)
500m (1.5 MB)
250m (3.8 MB)
Bands Used: 1, 4, 3
Credit: Jeff Schmaltz
MODIS Land Rapid Response Team,
NASA GSFC

The Caspian Sea dominates this image at the crossroads of Europe and Asia. The Caspian is just Southwest of the Ural Mountains, the traditional dividing line between the two continents. It is bordered by Russia and Azerbaijan to the West, Kazakhstan to the North, Turkmenistan to the East, and Iran to the South. The Caspian is the largest inland body of water in the world, measuring over 370,000 square kilometers (143,000 square miles). It is fed by the Volga and Ural Rivers, but it has no natural outlet; instead, water is lost primarily through evaporation. It is relatively shallow, measuring only about a 1 kilometer (0.6 miles) deep; in contrast, the deepest lake in the world (Lake Baikal) is 1.6 kilometers (0.9 miles) deep but only about 31,000 square kilometers (12,000 square miles) in area. The Caspian, although sometimes classified as a lake, is comprised of salt, not fresh, water. The Caspian Sea is a major source of sturgeon, a highly valuable type of fish that produces most of the world’s caviar.

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