Isla Santiago, Galapagos Islands

The island of Santiago is located near the center of the Galapagos Islands, off the coast of Ecuador. The Galapagos Islands are situated near the equator, and were formed from volcanism related to a large mantle plume (also known as a hot spot). This hot spot is very close to the tectonic boundary between the Galapagos Ridge—a plate boundary that is also an oceanic spreading center—and the Nazca and Cocos plates. This combination of mantle plumes and tectonic plate movements produces a unique geological environment, including underwater ridges of volcanoes that influence the water circulation around the Galapagos. All of these aspects contribute to the geology and biology of the Galapagos.

Isla Santiago itself was formed from a shield volcano (also called Santiago). This type of volcanic structure is recognized by low, flat summits surrounded by extensive flow fields of lava; the lava is not very viscous, so it can flow for great distances from the source vents. Several dark lava flow fields are visible in this astronaut photograph, the largest along the eastern, western, and southern coastlines. The small Isla Rábida to the south is the peak of another, mostly submerged shield volcano. (Note that the image is rotated so that south is to the top left.)

In addition to the lava flows, other volcanic features known as tuff cones are visible on the eastern and western sides of the island. These cones are formed by the rapid interaction of hot flowing lava and water. The water underneath the lava flow flashes to steam explosively, and this both fragments the lava and rapidly cools it, leading to the formation of cones of glassy, relatively fine-grained volcanic material. The most recent volcanic activity on Isla Santiago occurred during 1904–1906.

The summit ridge of the Santiago shield volcano is located in the northwestern part of the island. Also at image center is a large but isolated region of green vegetation on the south-facing slope, below the summit ridge. This image was taken during the dry, or garúa, season that lasts from June to November. The season is dominated by cooler air transported by southeast trade winds and cooler waters from the Humboldt and Cromwell currents. The combination of cool air and water results in rain falling only in the island highlands, with south- and east-facing slopes receiving the most precipitation. Despite the favorable location, the yellow-green color of the vegetation may indicate water (or other) stress.

کسی می آید و آن دیگر می رود ؛ هر دو سوار بر باد- سفر بهاره -

سرک می کشم به پیرامون ِ " دامغان"؛ بهار در نیمه ی راه است .
" دامغان رود" همان است که در یورش ترکان سلجوقی بود؛ و قطره های آب همان ، که پیکر در هم ریخته ی مردما ن ِ با فرهنگ این دیا ر را با خود برد و بر پهنه ی کویر بر جای گذاشت و، در خاک شد . شیون ِ مردم به اسارت برده را باد این سو و آن سو می برد .
...
" دامغان رود" خود را به کستره ای از " پادگانه " ها ی آبرفتی ِ جوان پهن کرده است . دور وبرش را زمین های زیر کشت پوشانده است ؛ و نقطه های بدنبال هم بر زمین - مظهر قنات - که آبیاری اش می کند.
...
جای پای دودمان "قاجار " را در اسم آبادی های پراکنده در" پهن دشت آبرفتی و بادی "، می توان دید.
بلندی های شمال غربی ، پاره ای از تن البرز کوه است . تپه های جدا از هم ، در جنوب باختری و پهنه ی دامغان ، در سمت جنوب خاوری "دامغان"، سخاوتمندانه ، به شکوه و زیبایی این سرزمین پاک و "غمین"، افزوده است .
رودی از بلندی " گرکس" ، با چکاد 3623 متر از رویه ی دریا ، در بخش خاوری ، بر روی سنگهای 65 میلیون ساله می لغزد و سرود خوان می آید . - جای پای دایناسورها، بر پوسته ی جنبای ایران زمین نیز به زمان همین سنگها می رسد .-
...
" چهار ده کلاته" خود را بر بلندی " کنگلومرایی" چسبانده است . گسله ای بر آمده از جنبش " رهایی انرژی" از درون زمین ، راه بر رود می بندد. خاکستر آتشفشانی و ماسه سنگ و گچ ، همه نشان از تکاپوی شدید دارد.
"کلاته چهار ده" دیروز ، امروز نام " دیباج دارد .
...
زندگی ادامه دارد . کودکی می آید و از فردا می گوید و برادری می پرد و از دیروز می گوید . و این همان زندگی است . این زیبایی ، در آنی در چنگ ما می افتد و ... می پرد .

Scientists propose upper-mantle link between Kilauea and Mauna Loa

A new Rice University-led study finds that a deep connection about 50 miles underground can explain the enigmatic behavior of two of Earth’s most notable volcanoes, Hawaii’s Mauna Loa and Kilauea. The study, the first to model paired volcano interactions, explains how a link in Earth’s upper mantle could account for Kilauea and Mauna Loa’s competition for the same deep magma supply and their simultaneous “inflation,” or bulging upward, during the past decade.

Dust Storm Off Alaska

When glaciers grind against underlying bedrock, they produce a silty powder with grains finer than sand. Geologists call it “glacial flour” or “rock flour.” This iron- and feldspar-rich substance often finds its ways into rivers and lakes, coloring the water brown, grey, or aqua. When rivers or lake levels are low, the flour accumulates on drying riverbanks and deltas, leaving raw material for winds to lift into the air and create plumes of dust.

That’s what was happening on October 23, 2012, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image of northerly winds blowing a plume of dust from the Copper River delta out over the Gulf of Alaska. Large dust storms like this are most common in Alaska in the fall, when river levels are at their lowest. Satellites have observed similar events in recent years.

This dust storm was first noticeable in MODIS imagery on October 21 and continued through October 25. Though the plume extended for more than a hundred miles, it did not appear thick in comparison to some produced during previous events. A two-week event in 2006, for instance, which researchers described in detail in a paper inGeophysical Research Letters, produced large plumes that lofted between 30 and 80 kilotons of glacial flour into the atmosphere.

Since 2011, as part of a project to improve understanding of arctic dust storms and validate satellite observations, a team of NASA-funded scientists have been monitoring filtered air samples from a site on Middleton Island, a small island in the Gulf of Alaska. Scientists monitor Arctic dust for a number of reasons. The storms can reduce visibility enough to disrupt air travel, and they can also pose health hazards to people on the ground when they occur inland. The dust is also a key source of iron for phytoplankton, whose growth is limited by the availability of minerals and nutrients. Finally, there is the possibility that dust events are becoming more frequent and severe due to ongoingrecession of glaciers in coastal Alaska.

·      References

Crusius, J. (2011, July 10) Glacial flour dust storms in the Gulf of Alaska: Hydrologic and meteorological controls and their importance as a source of bioavailable iron. Geophysical Research Letters.

·      Gasso, S. (n.d.) It’s not all from Asia: Satellite observations of dust transport of Alaskan dust into the North Pacific (pdf).

Fresh Lava on Kilauea, Hawaii

Kilauea Volcano’s current eruption began in 1983, covering more than 120 square kilometers (48 square miles) of the island of Hawai’i in fresh lava. This false-color satellite image (top) shows how lava tubes carry fluid basalt more than 10 kilometers (6 miles) from Pu’u ’O’o, the center of the eruption.

Instead of the red, green, and blue light in a conventional photograph, the false-color image at the top of the page contains information in two invisible wavelengths (shortwave infrared and near infrared), and one visible wavelength (green). Old lava flows absorb light in all three wavelengths, so they appear dark. Molten lava—and, to a lesser extent, freshly solidified lava—“glows” in shortwave infrared light, but absorbs near infrared and green light, so it appears red. Vegetation is bright green, clouds are white or cyan, and the ocean is dark blue. The image was acquired by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite on October 13, 2012.

The 1983 eruption started at Pu’u ’O’o crater, which is the current site of upwelling lava. Despite being partially covered by clouds, Pu’u ’O’o is bright red in this image due to heat from the lava lake within. Lava flows from the crater towards the coast, hidden from view by insulated lava tubes. Some lava re-emerges from the tubes at the top of the pali—the steep slope that separates Kilauea’s eastern rift from the coastal plain.

The remainder of the lava continues through the tube network to the bottom of the pali, where it pools and eventually surfaces in broad lobes. According to the U.S. Geological Survey’s Hawai’ian Volcano Observatory, the lava is currently creeping across the coastal plain towards the ocean.

A photograph taken on October 4 (lower image) during a flight by USGS scientists shows the lava just as it reached the bottom of the pali. Most of the lava surface is dark in daylight. Only the hottest, most fluid lava glows orange or yellow. Gray volcanic plumes blowing from right to left trace the path of the lava flow down the pali.

1.  References

2.   USGS Hawaiian Volcano Observatory. (2011) Pu’u ’Ō’ō-Kupaianaha Kīlauea’s East Rift Zone Eruption 1983 to present.Accessed October 19, 2012.

3.   USGS Hawaiian Volcano Observatory. (2012, October 19) Kilauea Status Report. Accessed October 19, 2012.

·         Related Reading

·         Hawai’i Volcanoes National Park

·         Hawai’ian Volcan

Wake Island, Pacific Ocean

The atoll of Wake Island is located in the central Pacific Ocean, approximately 4,000 kilometers (2,500 miles) to the west-southwest of Hawaii and 2,400 kilometers (1,500 miles) to the northwest of Guam. In addition to Wake Island, the atoll includes the smaller Peale Island and Wilkes Island, for a total land surface area of 6.5 square kilometers (2.5 square miles). Like many atolls in the Pacific, the islands and associated reefs formed around a submerged volcano. The lagoon in the center of the islands marks the approximate location of the summit crater.

Wake Island was annexed by the United States of America in 1899, and it became an important military and commercial airfield by 1935. Following the bombing of Pearl Harbor and the mutual declaration of war between the U.S. and the Empire of Japan in 1941, the atoll was occupied by Japanese forces until the end of World War II in the Pacific (1945). Today, the civil administration of the atoll is the responsibility of the U.S. Department of the Interior, while the U.S. Air Force and Army maintain military facilities and operations (including an airfield and large ship anchorages). With the exception of direct support to missions—and potentially, emergency airplane landings—there are no commercial or civilian flights to Wake Island.

In 2006, Wake Island was in the path of Super Typhoon Ioke. Given the danger, the entire civilian and military population was evacuated. While some damage to buildings and facilities occurred as a result of the storm, a U.S. Air Force repair team subsequently restored full capabilities for strategic use of the atoll.

Astronaut photograph ISS033-E-7873 was acquired on September 27, 2012, with a Nikon D3S digital camera using a 400 millimeter lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 33 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by William L. Stefanov, Jacobs/ESCG at NASA-JSC.

Instrument: 

ISS - Digital Camera

City of Thunder Bay, Ontario, Canada

Ham Lake Fire, Minnesota and Ontario

Along the Minnesota-Ontario border, the Ham Lake Fire was billowing a thick cloud of smoke toward the east on May 10, 2007, when Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image. Places where MODIS detected actively burning fire are outlined in red. Smoke reaches the city of Thunder Bay, on the shores of Lake Superior.

According to reports from the National Interagency Fire Center on May 11, the fire was burning in timber and dead fuel, and had affected 50,000 acres. Only 5 percent contained, the blaze was threatening residences and commercial property and had forced evacuations in surrounding communities.

The large image provided above has a spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides twice-daily images of the region in additional resolutions and formats, including an infrared-enhanced version that highlights the burn scar on the ground.

City of Thunder Bay, Ontario, Canada

Located on the shores of Lake Superior (regional view), the metropolitan area of Thunder Bay is one of the largest in the Province of Ontario. It is also the major port providing access to the Great Lakes for central Canada’s grain products. The city of Thunder Bay is relatively new; it was incorporated in 1970 by combining the cities of Fort William (shown in this astronaut photograph) and Port Arthur with the townships of Neebing and McIntyre. While the spread of separate municipalities into a larger contiguous metropolitan area is common (urban geographers call the process agglomeration), it is less common for distinct cities to merge into a new political entity.

This detailed astronaut photograph is centered on the older city of Fort William, in the southern portion of Thunder Bay. Winter snows outline the street grid of the city, while parks appear as roughly rectangular areas of unbroken white snow. Built materials (buildings, streets) appear light gray, while vegetated areas and the rock outcrop near Mount McKay are dark green to dark gray. The Kam River to the south of Fort William is ice-covered, and has an even covering of snow that traces the river channel.

Astronaut photograph ISS018-E-11174 was acquired on December 6, 2008, with a Nikon D2Xs digital camera fitted with an 800 mm lens, and is provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 18 crew. The image in this article has been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption William L. Stefanov, NASA-JSC.

Instrument: 

ISS - Digital Camera

A Cosmic Wreath

A A Cosmic Wreath

NASA's Wide-field Infrared Survey Explorer (WISE) mission presents the "Wreath nebula." Though this isn't the nebula's official name (it's actually called Barnard 3, or IRAS Ring G159.6-18.5), one might picture a wreath in these bright green and red dust clouds -- a ring of evergreens donned with a festive red bow, a jaunty sprig of holly, and silver bells throughout. Interstellar clouds like these are stellar nurseries, places where baby stars are being born. 

The green ring (evergreen) is made of tiny particles of warm dust whose composition is very similar to smog found here on Earth. The red cloud (bow) in the middle is probably made of dust that is more metallic and cooler than the surrounding regions. The bright star in the middle of the red cloud, called HD 278942, is so luminous that it is likely what is causing most of the surrounding ring to glow. Inpowerful stellar winds are what cleared out the surrounding warm dust and created the ring-shaped feature in the first place. The bright greenish-yellow region left of center (holly) is similar to the ring, though more dense. The bluish-white stars (silver bells) scattered throughout are stars located both in front of, and behind, the nebula

Regions similar to this nebula are found near the band of the Milky Way galaxy in the night sky. The "wreath" is slightly off this band, near the boundary between the constellations of Perseus and Taurus, but at a relatively close distance of only about 1,000 light-years, the cloud is a still part of our Milky Way. 

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust. 

Image Credit: NASA/JPL-Caltech/UCLACosmic Wreath

Antarctic Sea Ice Reaches New Maximum Extent

Two weeks after a new record was set in the Arctic Ocean for the least amount of sea ice coverage in the satellite record, the ice surrounding Antarctica reached its annual winter maximum—and set a record for a new high. Sea ice extended over 19.44 million square kilometers (7.51 million square miles) in 2012, according to the National Snow and Ice Data Center (NSIDC). The previous record of 19.39 million kilometers (7.49 million square miles) was set in 2006.

The map above shows sea ice extent around Antarctica on September 26, 2012, when ice covered more of the Southern Ocean than at any other time in the satellite record. The map is based on an NSIDC analysis of data from the Special Sensor Microwave/Imagers flown in the Defense Meteorological Satellite Program. Land is dark gray, and ice shelves—which are attached to land-based glaciers but floating on the ocean—are light gray. The yellow outline shows the median sea ice extent in September from 1979 to 2000. Sea ice extent is defined as the total area in which the ice concentration is at least 15 percent.

The graph of NSIDC data shows the maximum extent for each September since 1979 in millions of square kilometers. There is a lot of variability from year to year, though the overall trend shows growth of about 0.9 percent per decade.

According to a recent study by sea ice scientists Claire Parkinson and Donald Cavalieri of NASA’s Goddard Space Flight Center, Antarctic sea ice increased by roughly 17,100 square kilometers per year from 1979 to 2010. Much of the increase, they note, occurred in the Ross Sea, with smaller increases in Weddell Sea and Indian Ocean. At the same time, the Bellinghausen and Amundsen Seas have lost ice. “The strong pattern of decreasing ice coverage in the Bellingshausen/Amundsen Seas region and increasing ice coverage in the Ross Sea region is suggestive of changes in atmospheric circulation,” they noted.

“The year 2012 continues a long-term contrast between the two hemispheres, with decreasing sea ice coverage in the Arctic and increasing sea ice coverage in the Antarctic,” Parkinson added. “Both hemispheres have considerable inter-annual variability, so that in either hemisphere, next year could have either more or less sea ice than this year. Still, the long-term trends are clear, but not equal: the magnitude of the ice losses in the Arctic considerably exceed the magnitude of the ice gains in the Antarctic.”

On their Arctic Sea Ice News and Analysis blog, scientists from the University of Colorado wrote: “Comparing winter and summer sea ice trends for the two poles is problematic since different processes are in effect. During summer, surface melt and ice-albedo feedbacks are in effect; winter processes include snowfall on the sea ice, and wind. Small changes in winter extent may be a more mixed signal than the loss of summer sea ice extent. An expansion of winter Antarctic ice could be due to cooling, winds, or snowfall, whereas Arctic summer sea ice decline is more closely linked to decadal climate warming.”

1.     References

2.     Parkinson, C.L., and D.J. Cavalieri (2012, August 15) Antarctic sea ice variability and trends, 1979-2010. The Cryosphere, Volume 6, pages 871-880.

3.     NASA Earth Observatory (2009, April 20) Sea Ice.

4.     NASA Earth Observatory (n.d.) World of Change: Antarctic Sea Ice.

5.     NASA (2009, September 1) What's Holding Back Antarctic Sea Ice from Melting. Accessed October 10, 2012.

6.     National Snow and Ice Data Center (2012, October 2) Poles Apart: A record-breaking summer and winter. Accessed October 10, 2012.

7.     The New York Times (2012, October 3) Running the Numbers on Antarctic Sea Ice.

NASA Earth Observatory images by Jesse Allen, using DMPS SSMIS ice concentration data provided courtesy of theNational Snow and Ice Data Center (NSIDC). Caption by Michael Carlowicz

Instrument: 

DMSP - SSMIS

NASA's WISE Colors in Unknowns on Jupiter Asteroids

New results from NASA's Wide-field Infrared Explorer, or WISE, reveal that the Jovian Trojans -- asteroids that lap the sun in the same orbit as Jupiter -- are uniformly dark with a hint of burgundy color, and have matte surfaces that reflect little sunlight. Image credit: NASA/JPL-Caltech

Scientists using data from NASA's Wide-field Infrared Survey Explorer, or WISE, have uncovered new clues in the ongoing mystery of the Jovian Trojans -- asteroids that orbit the sun on the same path as Jupiter. Like racehorses, the asteroids travel in packs, with one group leading the way in front of the gas giant, and a second group trailing behind. 

The observations are the first to get a detailed look at the Trojans' colors: both the leading and trailing packs are made up of predominantly dark, reddish rocks with a matte, non-reflecting surface. What's more, the data verify the previous suspicion that the leading pack of Trojans outnumbers the trailing bunch. 

The new results offer clues in the puzzle of the asteroids' origins. Where did the Trojans come from? What are they made of? WISE has shown that the two packs of rocks are strikingly similar and do not harbor any "out-of-towners," or interlopers, from other parts of the solar system. The Trojans do not resemble the asteroids from the main belt between Mars and Jupiter, nor the Kuiper belt family of objects from the icier, outer regions near Pluto. 

"Jupiter and Saturn are in calm, stable orbits today, but in their past, they rumbled around and disrupted any asteroids that were in orbit with these planets," said Tommy Grav, a WISE scientist from the Planetary Science Institute in Tucson, Ariz. "Later, Jupiter re-captured the Trojan asteroids, but we don't know where they came from. Our results suggest they may have been captured locally. If so, that's exciting because it means these asteroids could be made of primordial material from this particular part of the solar system, something we don't know much about." Grav is a member of the NEOWISE team, the asteroid-hunting portion of the WISE mission.