 |
|
NASA data show Arctic saw fastest August sea ice retreat on record
September 29, 2008Following a record-breaking season of arctic sea ice decline in 2007, NASA scientists have kept a close watch on the 2008 melt season. Although the melt season did not break the record for ice loss, NASA data are showing that for a four-week period in August 2008, sea ice melted faster during that period than ever before.
Each year at the end of summer, sea ice in the Arctic melts to reach its annual minimum. Ice that remains, or "perennial ice," has survived from year to year and contains old, thick ice. The area of arctic sea ice, including perennial and seasonal ice, has taken a hit in past years as melt has accelerated. Researchers believe that if the rate of decline continues, all arctic sea ice could be gone within the century.
"I was not expecting that ice cover at the end of summer this year would be as bad as 2007 because winter ice cover was almost normal," said Joey Comiso of NASA's Goddard Space Flight Center in Greenbelt, Md. "We saw a lot of cooling in the Arctic that we believe was associated with La Niña. Sea ice in Canada had recovered and even expanded in the Bering Sea and Baffin Bay. Overall, sea ice recovered to almost average levels. That was a good sign that this year might not be as bad as last year."
The 2008 sea ice minimum was second to 2007 for the record-lowest extent of sea ice, according to a joint announcement Sept. 16 by NASA and the University of Colorado's National Snow and Ice Data Center (NSIDC) in Boulder, Colo. As of Sept. 12, 2008, the ice extent was 1.74 million square miles. That's 0.86 million square miles below the average minimum extent recorded from 1979 to 2000, according to NSIDC.
Contributing to the near-record sea ice minimum in 2008 was a month-long period in the summer that saw the fastest-ever rate of seasonal retreat during that period. From August 1 to August 31, NASA data show that arctic sea ice extent declined at a rate of 32,700 square miles per day, compared to a rate of about 24,400 square miles per day in August 2007. Since measurements began, the arctic sea ice extent has declined at an average rate of 19,700 miles per day at the point when the extent reaches its annual minimum.
Observations of changes to sea ice over time are possible due to a 30-year record of data from NASA and other agency satellites, including Nimbus-7, Aqua, Terra and the Ice, Cloud, and land Elevation Satellite (ICESat).
Researchers say that the recent seasonal acceleration could be in part due to conditioning going on in the Arctic. For example, research by Jennifer Kay of the National Center for Atmospheric Research in Boulder, Colo., and colleagues reported this April in Geophysical Research Letters that reduced cloud cover in 2007 allowed more sunlight to reach Earth, contributing to a measureable amount of sea ice melt at the surface. Reduced cloud cover also contributed to warmer ocean surface temperatures that led to melting of the ice from below.
"Based on what we've learned over the last 30 years, we know that the perennial ice cover is now in trouble," Comiso said. "You need more than just one winter of cooling for the ice to recover to the average extent observed since the measurements began. But the trend is going the other way. A warming Arctic causes the surface water to get warmer, which delays the onset of freeze up in the winter and leads to a shorter period of ice growth. Without the chance to thicken, sea ice becomes thinner and more vulnerable to continued melt."
NASA/Goddard Space Flight Center
The 2008 sea ice minimum was second to 2007 for the record-lowest extent of sea ice, according to a joint announcement Sept. 16 by NASA and the University of Colorado's National Snow and Ice Data Center (NSIDC) in Boulder, Colo. As of Sept. 12, 2008, the ice extent was 1.74 million square miles. That's 0.86 million square miles below the average minimum extent recorded from 1979 to 2000, according to NSIDC.
Contributing to the near-record sea ice minimum in 2008 was a month-long period in the summer that saw the fastest-ever rate of seasonal retreat during that period. From August 1 to August 31, NASA data show that arctic sea ice extent declined at a rate of 32,700 square miles per day, compared to a rate of about 24,400 square miles per day in August 2007. Since measurements began, the arctic sea ice extent has declined at an average rate of 19,700 miles per day at the point when the extent reaches its annual minimum.
Observations of changes to sea ice over time are possible due to a 30-year record of data from NASA and other agency satellites, including Nimbus-7, Aqua, Terra and the Ice, Cloud, and land Elevation Satellite (ICESat).
Researchers say that the recent seasonal acceleration could be in part due to conditioning going on in the Arctic. For example, research by Jennifer Kay of the National Center for Atmospheric Research in Boulder, Colo., and colleagues reported this April in Geophysical Research Letters that reduced cloud cover in 2007 allowed more sunlight to reach Earth, contributing to a measureable amount of sea ice melt at the surface. Reduced cloud cover also contributed to warmer ocean surface temperatures that led to melting of the ice from below.
"Based on what we've learned over the last 30 years, we know that the perennial ice cover is now in trouble," Comiso said. "You need more than just one winter of cooling for the ice to recover to the average extent observed since the measurements began. But the trend is going the other way. A warming Arctic causes the surface water to get warmer, which delays the onset of freeze up in the winter and leads to a shorter period of ice growth. Without the chance to thicken, sea ice becomes thinner and more vulnerable to continued melt."
NASA/Goddard Space Flight Center
Sea Ice Current Events and Sea Ice News RSSVolcanoes cool the tropics, say researchers
Climate researchers have shown that big volcanic eruptions over the past 450 years have temporarily cooled weather in the tropics-but suggest that such effects may have been masked in the 20th century by rising global temperatures.
Snowy owl -- a marine species?
Wildlife satellite studies could lead to a radical re-thinking about how the snowy owl fits into the Northern ecosystem.
Getting Warmer? Prehistoric Climate Can Help Forecast Future Changes
The first comprehensive reconstruction of an extreme warm period shows the sensitivity of the climate system to changes in carbon dioxide (CO2) levels as well as the strong influence of ocean temperatures, heat transport from equatorial regions, and greenhouse gases on Earth's temperature.
Ecologists use oceanographic data to predict future climate change
Ecologists and oceanographers are attempting to predict the future impacts of climate change by reconstructing the past behavior of Arctic climate and ocean circulation.
Very cold ice films in laboratory reveal mysteries of universe
The universe is full of water, mostly in the form of very cold ice films deposited on interstellar dust particles, but until recently little was known about the detailed small scale structure.
Arctic sea ice thinning at record rate
The thickness of sea ice in large parts of the Arctic declined by as much as 19% last winter compared to the previous five winters, according to data from ESA's Envisat satellite.
Research around the North Pole
The German research vessel Polarstern has returned today to Bremerhaven from the Arctic Sea. It has cruised as the first research vessel ever both the Northeast and the Northwest Passages and thereby circled the North Pole.
NASA study finds rising Arctic storm activity sways sea ice, climate
A new NASA study shows that the rising frequency and intensity of arctic storms over the last half century, attributed to progressively warmer waters, directly provoked acceleration of the rate of arctic sea ice drift, long considered by scientists as a bellwether of climate change.
Arctic sea ice hits second-lowest extent, likely lowest volume, say CU-Boulder researchers
Arctic sea ice extent during the 2008 melt season dropped to the second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on Sept. 14.
Arctic sea ice annual freeze-up underway
After reaching the second-lowest extent ever recorded last month, sea ice in the Arctic has begun to refreeze in the face of autumn temperatures, closing both the Northern Sea Route and the direct route through the Northwest Passage.
More Sea Ice Current Events and Sea Ice News Articles
 | Sea of Ice: The Wreck of the Endurance (Step into Reading, Step 4, paper) by Monica Kulling In 1914 Sir Ernest Shackleton set out with his crew aboard the ship the Endurance. He wanted to sail to Antarctica, but 100 miles from the South Pole, the Endurance became trapped in a sea of ice. Against all odds, Shackleton undertook a journey that led to the rescue of this crew after almost two years of nail-biting survival. Based on a true... |
 | Beyond the Sea of Ice: The First Americans, Book 1 by William Sarabande A vividly told, historically detailed story of the human origins of our land, this first book of a planned multi-book series follows Torka, a particularly brave and intelligent hunter, as he leads his tribe to safety from fierce animals, harsh cold and the enemies who would enslave them.... |
 | Secrets of the Ice Ages: The Role of the Mediterranean Sea in Climate Change by Robert G. Johnson In easy historical steps, this book describes the efforts of scientists to understand why ice ages have occurred and the evidence for the role that the Mediterranean Sea plays in the grand sequence of climate changes over the last three million years. You will see how the orbital theory of ice ages advocated by Croll and Milankovitch passed through cycles of scientific acceptance and rejection... |
 | Beyond the Sea of Ice: The Voyages of Henry Hudson (Great Explorers) by Joan Elizabeth Goodman, Fernando Rangel It was there. Henry Hudson was certain of it. Beyond the impenetrable fog and crushing ice of the North Atlantic lay the dream of kings, merchants and learned geographers - a passage to the Orient. Sailing small wooden boats well above the arctic circle, guided by maps and charts that were based on rumor and hope as much as fact, surrounded by crews that shared neither his belief nor... |
 | Sea Ice: An Intorduction to its Physics, Chemistry, Biology and Geology Sea ice, which covers up to 7% of the planet’s surface, is a major component of the world’s oceans, partly driving ocean circulation and global climate patterns. It provides a habitat for a rich diversity of marine organisms, and is an extremely valuable source of information in studies of global climate change and the evolution of present day life forms. Increasingly sea ice is being used as... |
 | Sea-Ice and Iceberg Sedimentation in the Ocean by Alexander P. Lisitzin In many geological epochs, glacial sediments are widespread. This type of sedimentation results from the interaction between atmosphere, cryosphere, hydrosphere and biosphere under temperatures ranging from 0 to -80. Two types of glacial sediments exists: those from sea-ice and those from icebergs. Both types can be subdivided into various subfacies. Most widespread in the Northern Hemisphere is... |
 | Into the Ice Sea: Barents' Wintering on Novaya Zemlya - A Renaissance Voyage of Discovery by Jaapjan Zeeberg Archaeologists connected with Amsterdam's Rijksmuseum journeyed into the Russian Artic to rediscover the graves, ship, and wintering cabin of Willem Barents' expedition, lost 400 years ago on the shores of a remote Arctic Island while chartinga passage to Asia. Into the Ice Sea is the account of several expeditions during the 1990s and their historical parallels of four centuries. This is a book... |
| The Sea and the Ice: A Naturalist in Antarctica by Louis J. Halle | |
| Sea ice, climate, and Icelandic fisheries in the eighteenth and nineteenth century.: An article from: Arctic by A.E.J. Ogilvie, J. Jonsdottir This digital document is an article from Arctic, published by Arctic Institute of North America of the University of Calgary on December 1, 2000. The length of the article is 8482 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web... | |
 | The Biblical Flood: Global Warming & Bush's Harvest by William W Morgan It is generally agreed by all reputable, mainstream climatologist that Global Warming is real. That there will be rising sea levels and temperature changes ranging from an ice age to desertification of large parts of the planet. With our present societal system based on coercion we have Global Dumbing. The result will be uncontrollable disorder and chaos, preventing us from solving the... |
| © 2009 BrightSurf.com |