Showing posts with label NASA. Show all posts

Written by fatih al-farahat in , ,


In Search of Ninja Asteroids

We are living through a glorious age of exploration of our solar system. This particular tool will begin the task of ferreting out a proper map of all significant objects in nearby solar orbit.

Obviously we expect to find a lot of material that is worth tracking.

I am not nearly so exercised over possible impacts as some because our efforts have shown us that these events are super rare and most everything is nicely managed by Jupiter.

It is most likely the reason that Venus does not have a supply of water yet. Mankind’s future task will be to change that, after we are properly finished here. Then we will have two planets to live on comfortably.

I am pleased that this protocol will work. I would certainly have expected problems there.

The next big push, once we have a source of energy such as the focus fusion device, will be to spread a number of such scopes out into the solar system to form a large globe based initially on Earth’s orbit and naturally able to collect data on the inner solar system inside the orbit of Jupiter.

This all will be much sooner than anyone thinks. We have the technology and we have the teams in place to make it happen. It is all waiting for the necessary fusion powered one g thruster. As is also our first manned trip to Mars. Without a one g thruster, exploring Mars with a thousand rovers looks like a wonderful idea and certainly many times more effective.

In Search of Dark Asteroids (and Other Sneaky Things) 09.15.2009

In modern warfare, though, ninjas would be sitting ducks. Their black clothes may be hard to see at night with the naked eye, but their warm bodies would be clearly visible to a soldier wearing infrared goggles.

To hunt for the "ninjas" of the cosmos — dim objects that lurk in the vast dark spaces between planets and stars — scientists are building by far the most sensitive set of wide-angle infrared goggles ever, a space telescope called the Widefield Infrared Survey Explorer (WISE).

WISE will scan the entire sky at infrared wavelengths, creating the most comprehensive catalog yet of dark and dim objects in the cosmos: vast dust clouds, brown dwarf stars, asteroids — even large, nearby asteroids that might pose a threat to Earth.

Surveys of nearby asteroids based on visible-light telescopes could be skewed toward asteroids with more-reflective surfaces. "If there's a significant population of asteroids nearby that are very dark, they will have been missed by these previous surveys," says Edward Wright, principal investigator for WISE and a physicist at the University of California in Los Angeles.

The full-sky infrared map produced by WISE will reveal even these darker asteroids, mapping the locations and sizes of roughly 200,000 asteroids and giving scientists a clearer idea of how many large and potentially dangerous asteroids are nearby. WISE will also help answer questions about the formation of stars and the evolution and structure of galaxies, including our own Milky Way.

And the discoveries won't likely stop there.

"When you look at the sky with new sensitivity and a new wavelength band, like WISE is going to do, you're going to find new things that you didn't know were out there," Wright says.

Stars emit visible light in part because they're so hot. But cooler objects like asteroids emit light too, just at longer, infrared wavelengths that are invisible to the unaided eye. In fact, any object warmer than absolute zero will emit at least some infrared light.

Unfortunately, this fact makes building an infrared telescope rather difficult. Without a coolant, the telescope itself would glow in infrared light just like all other warm objects do. It would be like building a normal, visible-light telescope out of Times Square billboard lights: The telescope would be blinded by its own glow.

To solve this problem, WISE will cool its components to about 15°C above absolute zero (or -258°C) using a block of solid hydrogen. Mission scientists chose solid hydrogen over liquid helium, which is often used in research for cooling materials to near absolute zero, because a smaller volume of solid hydrogen can do the job. "The cooling power is much higher for hydrogen than for helium," Wright explains. When launching a telescope into space, being smaller and lighter saves money.

Previous space telescopes such as the Infrared Astronomical Satellite (IRAS) have mapped the sky at infrared wavelengths before, but WISE will be hundreds of times more sensitive. While other missions could only see diffuse sources of infrared light such as large dust clouds, WISE will be able to see asteroids and other point sources.

After it launches into orbit as early as this December, WISE will spend 6 months mapping the sky, during which it will download its data to ground stations 4 times each day. Analyzing that data should give scientists some new insights into the cosmos.

For example, one theory posits that most of the stars in the Universe were formed in the press of colliding galaxies. When galaxies collide, interstellar clouds of gas and dust smash together, compressing the clouds and starting a self-perpetuating cycle of gravitational collapse. The result is a flurry of starbirth. Newborn stars are usually concealed by the dusty clouds they are born in. Ordinary light cannot escape, but infrared light can.

WISE will be able to detect infrared emissions from the most active star-forming regions. This will help scientists know how rapidly stars are formed during galactic collisions, which could indicate how many of the universe's stars were formed this way.
'
WISE will also target dim "failed stars" called brown dwarfs that outnumber ordinary stars by a wide margin. Mapping brown dwarfs in the Milky Way may reveal much about the structure and evolution of our own galaxy.

And this could be just the beginning of the discoveries scientists make once WISE puts the spotlight on stealthy denizens of the dark.

Written by fatih al-farahat in , ,


Hubble Begins Second Life




This latest from the Hubble is the first set of images post refurbishment and they tell us that it is better than ever. So we will continue to get great images from this source.

Other important scopes are also now operating here on earth and we are getting hugely improved resolution there also.

I suspect that someone is going to establish a system down in the deep Antarctic to take advantage of the exceptional viewing conditions there. It may actually provide a reason to build a haulage road to the Polar Regions. It will be a challenge to develop equipment able to operate there but it will he well worth it.

At least we see the opportunity and can check it out.

Anyway the final link will take you to a Gallery of new images. This is a great time to visit the Hubble site and to refresh yourself on their accomplishments. It likely has been the most important contributor to pure science in the past two decades and has encouraged an expansion of scopes and astronomers to put many more eyes to work.


Spectacular First Images from the Rejuvenated Hubble Space Telescope

September 9, 2009: Astronomers have declared NASA's Hubble Space Telescope a fully rejuvenated observatory with the release of observations from four of its six operating science instruments. Sen. Barbara Mikulski of Maryland unveiled the images today at NASA Headquarters in Washington, DC.

"This marks a new beginning for Hubble," said Ed Weiler, associate administrator for NASA's Science Mission Directorate. "The telescope was given an extreme makeover and now is significantly more powerful than ever, well-equipped to last into the next decade."

Topping the list of new views are colorful, multi-wavelength pictures of far-flung galaxies, a densely packed star cluster, an eerie "pillar of creation," and a "butterfly" nebula. Hubble's suite of new instruments allows it to study the universe across a wide swath of the light spectrum, from ultraviolet all the way to near-infrared. In addition, scientists released spectroscopic observations that slice across billions of light-years to probe the cosmic-web structure of the universe and map the distribution of elements that are fundamental to life as we know it.

"I fought for the Hubble repair mission because Hubble is the people's telescope," said Mikulski, chairwoman of the Commerce, Justice and Science Appropriations Subcommittee that funds NASA. "I also fought for Hubble because it constantly rewrites the science textbooks. It has more discoveries than any other science mission. Hubble is our greatest example of our astronauts working together with scientists to show American leadership and ingenuity."

"I want to salute Team Hubble -- everyone who worked on Hubble from the Goddard Space Flight Center and Space Telescope Science Institute scientists in Maryland, to the ground crew at the Kennedy Space Center, to the Johnson Space Center where the astronauts train, and to the astronauts who were heroes in space," she concluded.

The new instruments are more sensitive to light and, therefore, will improve Hubble's observing efficiency significantly. It is able to complete observations in a fraction of the time that was needed with prior generations of Hubble instruments. The space observatory today is significantly more powerful than it ever has been.

http://hubblesite.org/newscenter/archive/releases/2009/25/image/ac/



Above: A sample spectrum obtained by Hubble's new Cosmic Origins Spectrograph (COS). More examples of COS data may be found here and here.

The new results are compelling evidence of the success of the STS-125 servicing mission in May, which has brought the space observatory to the apex of its scientific performance. Two new instruments, the Wide Field Camera 3 and Cosmic Origins Spectrograph, were installed, and two others, the Advanced Camera for Surveys and Space Telescope Imaging Spectrograph, were repaired at the circuit board level. Mission scientists also announced that the Near Infrared Camera and Multi-Object Spectrometer have been brought back into operation during three months of calibration and testing.

Right: Hubble's newly repaired Space Telescope Imaging Spectrograph (STIS) has revealed a stream of charged particles emerging from doomed star Eta Carina. [more]

http://imgsrc.hubblesite.org/hu/db/images/hs-2009-25-av-small_web.jpg

"On this mission we wanted to replenish the 'tool kit' of Hubble instruments on which scientists around the world rely to carry out their cutting-edge research," said David Leckrone, senior project scientist for Hubble at NASA's Goddard Space Flight Center in Greenbelt, Md. "Prior to this servicing mission, we had only three unique instrument channels still working, and today we have 13. I'm very proud to be able to say, 'mission accomplished.' "

Hubble now enters a phase of full science observations. The demand for observing time will be intense. Observations will range from studying the population of Kuiper Belt objects at the fringe of our solar system to surveying the birth of planets around other stars and probing the composition and structure of extrasolar planet atmospheres. There are ambitious plans to take the deepest-ever near-infrared portrait of the universe to reveal never-before-seen infant galaxies that existed when the universe was less than 500 million years old. Other planned observations will attempt to shed light on the behavior of dark energy, a repulsive force that is pushing the universe apart at an ever-faster rate.

Hubble is back and better than ever. Let the observing begin!

For images and more information about the Hubble Space Telescope, visit

http://www.nasa.gov/hubble

Written by fatih al-farahat in , ,


Space Debris Tamed




The problem has been quantized better and we have doable project that is able to harvest the objects that are in fact critical or I at least assume so. This suggests that objects not in this mix are at least survivable. Otherwise it is a good plan and puts hardware in orbit able to act as the local fire department

This is certainly a better scenario than previously espoused and based on little good data. A solution is available and it is cost effective. Loses of inaction will exceed that of implementation and if that is true then a common program needs to be put to work perhaps paid for on a per pound recovery charge so no one can squabble over whose fault.

I suspect that it will take some time for all this to be made to happen but the ability to charge back to the source programs will bring interest levels up. The problem is measurable and users can calculate their liability. This at least makes it a sufficiently solvable problem.

Debris - Problem Solved

http://www.spacedaily.com/reports/Space_Debris_Problem_Solved_999.html

Although space debris proliferation presents a long-term challenge that will require a long-term solution, the immediate problem is quite bounded. A study of debris distribution reveals the near-term troubled zone to be a spherically symmetric region between the altitudes of 700 km and 900 km.

by Launchspace Staff

Bethesda MD (SPX) Aug 31, 2009
There is no doubt that the topic of "space debris" is hot! It is a hot subject at
NASA, DARPA, Air Force Space Command, ESA and in the board rooms of all commercial satellite operators. High anxiety is running rampant among these groups. Every debris mitigation technique has been reviewed and pursued. New satellites must have the ability to either de-orbit or move out of the way at end-of-mission.

Upper stages must vent tanks to rid them of residual propellant that might later result in explosions. Many satellites are maneuvered to avoid close-conjunction events. JSpOC is beefing up its satellite and debris tracking capabilities. National and international working groups are meeting regularly to assess the threat and to recommend actions for all space-faring nations. The world is just one major satellite collision event away from panic.

Instances of close conjunction events in highly congested orbital bands have increased dramatically in the past few years. In fact, the frequency of close encounters between active satellites and large debris objects within the Iridium constellation has reached a frighteningly high level. Odds are that there will be another Iridium/Cosmos type of event in the near future.

Should such an event occur, several bad things will happen to many satellite operators. If another Iridium satellite is involved the company would be forced to replace the lost satellite. The frequency of close encounters in orbits near that of Iridium's constellation would suddenly increase to levels that would cause several operators to reassess the viability of existing space applications.

Satellite insurance providers might be forced to raise premiums on in-orbit performance to record high levels. Future launch plans for almost all low orbit satellites may be curtailed. Space-based services to the world would diminish over time. The economic impact is not even calculable. This is scary!

Not to fear. A solution is on the way.

Although space debris proliferation presents a long-term challenge that will require a long-term solution, the immediate problem is quite bounded. A study of debris distribution reveals the near-term troubled zone to be a spherically symmetric region between the altitudes of 700 km and 900 km.

This is where a great many operational satellites and large debris objects co-exist. Thus, the near-term challenge appears to be the removal of enough large debris objects in order to reduce collision risks to levels consistent with statistical times-between-debris-collisions that are much higher than expected satellite mission lifetimes.

Sounds simple, but it is not! Seems impossible, but it is not! So, what will it take to do the job?

Simply stated, all affected parties must collaborate and contribute to create a massive new space effort. There are literally well over 1,000 large debris objects that pose an immediate threat. Every one of these can be removed, and there are a number of removal techniques. One approach, as an example, would be to develop specially designed "Debris Collection Spacecraft."

Each DCS would be capable of maneuvering and rendezvousing with several objects, one at a time. Each object may be stored for later de-orbit, or fitted with an autonomous de-orbit unit that slows the object's orbital speed. If each DCS can deal with 100 objects, assuming only 1,000 objects need to be removed, the job will require 10 DCSs. This whole removal operation must be transparent to commercial, civil and security satellite operators.

In order to be effective, the removal program needs to start yesterday, because it will take several years before actual removal operations can begin. We don't have a lot of time here. If each of 100 objects being collected by one DCS takes three days of maneuvering to reach, then each DCS would require roughly 10 months to achieve its mission. However, it is likely that the DCSs will require in-orbit refueling after each 10 rendezvous completions.

The total mission span for each DCS seems to be roughly one year. If the program is started immediately, it could be completed in about five or six years. The program cost is estimated at $3 billion, based on developing the DCS, on-orbit refueling vehicles and operations, building 10 DCSs and one to two years of ground operations. This is cheap compared to the cost of not doing it.

For all those who are concerned and interested in the space debris crisis, your first step is to get smart on the issues and possible solutions. This is where Launchspace can help. If you are involved in space flight or want to better understand the new space crisis, you will want to sign up for the "must take" seminar on the subject, October 27th in Washington, DC.

Written by fatih al-farahat in , ,


Lunar Rock Oxygen


I thought that someone would have gotten serious about this a long time ago. Anyway, what is described is simple brute force methods. I sort of prefer a electrolytic system that does give of CO2 first because that is easily passed into a life supporting environment that can actively produce atmospheric oxygen and avoid a need for exotic chemical systems. Life is already there and has all the built in buffers.

In the event, provided we arrive on the moon or anywhere else in some form of efficient manner that supports a long term stay, then cheap power will be our most available raw material. We would have little reason to be there otherwise.

Cheap power can produce any element to hand sooner or later, even if it is a byproduct. Thus elemental oxygen is certainly an option. It also indcates that space exploration will have to wait for cheap light fusion power produced by a devise similar to that of Focus Fusion.

Only a few metals are legitimately concentrated in space, making beneficiation a difficult trick. Cheap power opens the door to lifting material out of the gravity well of Earth or any other natural concentrator tricky as that might be. Once we have cheap power and large enough magnetic bubble craft, mass lifting should be possible to support space construction.

It is also easily forgotten that mineral beneficiation is actually quite dependent on gravity on Earth. Most material that is rich usually has a significant specific gravity allowing some form of mass enrichment as a first simple step. It is only then that we reach for chemicals and energy.

PhysOrg.com) -- If humans ever create a lunar base, one of the biggest challenges will be figuring out how to breathe. Transporting oxygen to the moon is extremely expensive, so for the past several years NASA has been looking into other possibilities. One idea is extracting oxygen from moon rock.


http://www.physorg.com/news169216598.html#top

Recently, Derek Fray, a materials chemist from the University of Cambridge, and his colleagues have built a reactor that uses oxides in Moon rocks as the cathode in an electrochemical process to produce oxygen.

The design is based on a process that the researchers invented in 2000 that produces carbon dioxide. In this design, the scientists pass a current between the cathode and an anode made of carbon, with both electrodes sitting in an electrolyte solution of molten calcium chloride, a common salt. The current removes oxygen atoms from the cathode, which are then ionized and dissolve in the molten salt. The negatively charged oxygen is attracted to the carbon anode, where it erodes the anode and produces carbon dioxide.

To produce oxygen rather than carbon dioxide, the researchers made an unreactive anode using a mixture of calcium titanate and calcium ruthenate instead of the carbon. Because this anode barely erodes, the reaction between the oxygen ions and anode produces oxygen.

Based on experiments with a simulated lunar rock developed by NASA, the researchers calculate that three one-meter-tall reactors could generate one tonne of oxygen per year on the Moon. Each tonne of oxygen would require three tonnes of rock to produce. Fray noted that three reactors would require about 4.5 kilowatts of power, which could be supplied by solar panels or possibly a small nuclear reactor on the Moon. The researchers are also working with the European Space Agency on developing an even larger reactor that could be operated remotely.


As a recent story in Nature News reports, other researchers are also developing methods for oxygen extraction. For instance, Donald Sadoway at MIT is working on a high-temperature technique called molten salt electrolysis. Here, the Moon rock is molten and acts as the electrolyte itself. Sadoway's reactor could even be built out of the rubble on the Moon's surface called regolith.

NASA and the ESA are strongly encouraging this type of research. In 2008, NASA boosted its $250,000 prize to $1 million for the first team to demonstrate a method to extract five kilograms of oxygen in eight hours from simulated Moon rock. So far, the prize remains unclaimed.

Written by fatih al-farahat in , ,


Polar Bears and 2012

I find it very hard to get too exercised over the fate of the polar bears when by all calculations; their populations are at a peak. The only place they are under pressure, and quite frankly, it is pressure to go back further north where the season is clearly longer, is the bottom of Hudson Bay. If they simply developed a habit of migrating north in the spring they would be in great shape.

If anything, an expansion of their food stocks has likely expanded the population and as the ice disappears further, I expect that seal stocks will increase further supporting more bears.

There is presently conversation saying that the areal extent of this summer’s sea ice will not approach that of 2007. True so far as that goes. The wind has not returned and the ice pack is not concentrating. The ice itself is continuing to get thinner and thinner with each passing year. The downward collapse spiral is well entrenched and becoming more obvious. My prediction in 2007 for clear seas of sorts for 2012 is looking better every month.

It may well take 2007 type winds to actually clear these seas in 2012 or sooner. I think now that some new winter ice may last about two years as it rotates through the Arctic Gyre. In the meantime, three year and older is essentially getting eaten up if much is now left at all. In fact, that is perhaps the important question that needs to be asked. NASA has an expedition out there this summer and I am quite sure they are trying to map the real present extent of multi year ice.

If most multi year ice disappears by 2012, then sea ice coverage will consist of fairly thin one and two year ice that will be vulnerable to any decent wind system, even though it may still provide a sea ice cover as erratic as that presently in the Bay. The chances are that this can still provide huge tracts of open water in late August in most years throughout the high Arctic.

Thin ice for arctic beasts

Last Updated: July 23. 2009 3:04PM UAE / July 23. 2009 11:04AM GMT

http://www.thenational.ae/apps/pbcs.dll/article?AID=/20090725/MAGAZINE/707249922/-1/NEWS

The world’s largest land-based hunters, polar bears stand on the edge of rapid decline, unable to adapt quickly to a shrinking habitat as Arctic sea ice melts. Last year the US government added the animal to its threatened species list, but Tim Skelton examines whether it’s too little too late.

Images of starving polar bears are a poignant symbol of the state of our planet. When, in May 2008, the US government added the animal to its threatened species list, it became the first large mammal recognised as being in decline as a result of global warming. Polar bears have a major problem. Their habitat is changing fast, and it’s threatening their survival. Moreover, it won’t just be the bears that are affected. As the Arctic region’s top predator, their disappearance would have an impact on the entire food chain.

The world’s largest land-based hunters, adult male bears can weigh 750kg. They are perfectly adapted to cold climates, with fur designed to trap heat, and furry feet giving good grip on ice. They spend winters on the Arctic sea ice, and are expert seal hunters. But summers are a different story. When the ice melts they spend their time on land fasting, shedding a kilogram a day.This unusual fast/feast cycle worked well until global warming upset the balance. In summer 2007, satellite images revealed that Arctic sea ice retreated to a record level many climatologists had predicted would not happen until 2050. A US Geological Survey report concluded that two-thirds of the polar bear’s habitat could disappear by 2050. And some experts believe sea ice may have passed a point of no return, and may disappear entirely during the summer within 25 years.

Researchers from NASA and the Canadian Wildlife Service have also published a study on the extent of sea ice since 1978. Focussing on Canada’s western Hudson Bay region, they found the ice there was breaking up earlier and earlier, shortening the polar bears’ hunting season by three weeks. “If they feed for a shorter time, they’re going to accumulate less fat,” said Ian Stirling, a polar bear expert with the Canadian Wildlife Service, and co-author of the study. “At the same time, they’re going to be on land and fasting for longer.”

The bears have few food options on land, and must scavenge for whatever they can find. “There are a few sources of nutrition, but not enough to sustain the population,” Stirling said. The lack of food has even forced some animals to resort to cannibalism.Another effect of diminishing ice is that bears must swim longer distances across open water, further depleting their energy. This has led to an increase in cases of drowning. Moreover, as females become thinner, their reproductive rates drop and the survival chances of their cubs declines. The average weight of female bears dropped from 290kg in 1980 to 230kg in 2004.

The global population of polar bears has actually doubled since 40 years ago. Widespread hunting had driven numbers to a low of 12,000 in the 1960s, and a rebound occurred when strict controls were introduced. Today the global population is thought to be 20,000 to 25,000.But this apparently good news is hugely misleading. Virtually all experts agree a time bomb is ticking, and a rapid decline is imminent. With the Arctic warming faster than anywhere else on the planet, the bear’s natural habitat is changing too quickly for them to adapt.

Significant falls in local populations have already been observed. Numbers in the western Hudson Bay region declined from 1,200 in 1987 to 950 in 2004, a 22% drop. Unfortunately, because hungry bears congregate around human settlements in the hope of scavenging for food, native Inuit hunters actually see more bears than they used to. Some treat this as evidence the population is growing.Overall, the US Geological Survey predicts two-thirds of the world’s polar bear population will disappear by 2050, vanishing from all but their most northerly ranges. By 2080, there may only be a few remaining. The US government’s decision to list the bear as “threatened” is a step in the right direction. But it may be too late.

The future doesn’t look bright. But the polar bears’ one remaining trump card may well be their appearance. Despite their ferocious nature, we perceive them as “cute”. When we see them on TV, we sit up and take notice. So with documentary films such as Earth bringing the animal’s suffering right into our living rooms, their plight has become impossible to ignore. For thousands of years, polar bears have been an integral part of the Arctic. If they are going to be around for another thousand, it’s time to act now.

Written by fatih al-farahat in , , ,


Arctic Sea Ice Collapse Beginning

For some reason this is my week for sea ice. This report is additional confirmation of the present rapidity of the ice loss. They still talk of averages which misleads. Understanding that the ice reduction is best modeled on the basis of a constant size withdrawal, you get an accelerating effect that is now beginning to be very noticeable.

Simple calculation led me to project clear summer seas as early as 2012 back in 2007. NASA woke up and followed suit a few months later. We were all ignored since the press is never going to understand a non linear behavior.

Any way if the average loss has been seven inches a year over the past four years, then the present decline rate is likely around nine inches for this year. Figure ten or so next year and a foot thereafter and we are ice free in 2012. We simply do not have enough multi year ice left to make an iota of difference.

After all the ice has been cleared, we will see a new regime in which winter ice will go through a spring breakup and a swift removal that could be complete as early as mid July. This would provide a comfortable two month sailing season over the top.
Present indications suggest that we are in fact on our way to possibly losing all our multi year sea ice within the next five years. This report and others tell us we can not waffle anymore. In fact this report waffles by not pointing out that this loss is huge by any comparison.

Satellite survey reveals dramatic Arctic sea-ice thinning

http://environmentalresearchweb.org/cws/article/yournews/39779

Scientists have evaluated for the first time how much the thickness and volume of Arctic sea ice, not just the ice's surface area, have shrunk since 2004 across the Arctic Ocean basin. Even where the sea ice cover persists despite climate change in the region, a vast portion of the remaining ice layer has become thinner than it used to be, the new study finds.

"Even in years when the overall extent of sea ice remains stable or grows slightly, the thickness and volume of the ice cover is continuing to decline, making the ice more vulnerable to continued shrinkage," says Ron Kwok, senior research scientist at NASA's Jet Propulsion laboratory in Pasadena, Calif., and leader of the study.

Kwok and colleagues at NASA and the University of Washington, in Seattle, report that Arctic sea ice thinned dramatically between the winters of 2004 and 2008, with thin seasonal ice replacing thick, older ice as the dominant type for the first time on record.

Using ICESat measurements, scientists found that overall Arctic sea ice thinned about 17.8 centimeters (7 inches) a year, for a total of 67 cm (2.2 feet) over four winters. The total area covered by the thicker, older, multi-year ice that survives one or more summers shrank by more than 40 percent.

The team's findings were published today, Tuesday 7 July, in the Journal of Geophysical Research-Oceans, a publication of the American Geophysical Union (AGU). The researchers used measurements from NASA's Ice, Cloud and land Elevation Satellite (ICESat) to generate the first basin-wide estimate of the thickness and volume of the Arctic Ocean's ice cover. The data covers the period from the fall of 2003 through the winter of 2008.

Kwok says the results offer a better understanding of the regional distribution of thick and thin ice in the Arctic, presenting a much more telling picture of what's going on in the Arctic than measurements of how much of the Arctic Ocean is covered in ice alone can.

"Ice volume allows us to calculate annual ice production and gives us an inventory of the freshwater and total ice mass stored in Arctic sea ice," he notes. "Our data will help scientists better understand how fast the volume of Arctic ice is decreasing and how soon we might see a nearly ice-free Arctic in the summer."
The Arctic ice cap grows each winter as the sun sets for several months and intense cold sets in. In the summer, driven by wind and ocean currents, some of that ice naturally flows out of the Arctic, while much of it melts in place. But not all of the Arctic ice thaws each summer: the thicker, older ice is more likely to survive. Seasonal sea ice usually reaches about 1.83 meters (6 feet) in thickness, while multi-year ice averages 2.74 m (9 ft).

In recent years, however, the amount of ice replaced in the winter has not been sufficient to replace summer ice losses. This leads to more open water in summer, which then absorbs more heat, warming the ocean and further melting the ice. Between 2004 and 2008, multi-year ice cover shrank 42 percent, or 1.54 million square kilometers (595,000 square miles) – nearly the size of Alaska's land area.

During the study period, the relative contributions of the two ice types to the total volume of the Arctic's ice cover did a complete flip-flop. In 2003, 62 percent of the Arctic's total ice volume was stored in multi-year ice, with 38 percent stored in first-year seasonal ice. By 2008, 68 percent of the total ice volume was first-year ice, with 32 percent multi-year.

Study co-author and ICESat Project Scientist Jay Zwally of NASA's Goddard Space Flight Center, Greenbelt, Md., says ICESat makes it possible to monitor ice thickness and volume changes over the entire Arctic Ocean for the first time.

"One of the main things that has been missing from information about what is happening with sea ice is comprehensive data about ice thickness," says Zwally. "U.S. Navy submarines provide a long-term, high-resolution record of ice thickness over only parts of the Arctic. The submarine data agree with the ICESat measurements, giving us great confidence in satellites as a way of monitoring thickness across the whole Arctic Basin."

The authors attribute the changes in the overall thickness and volume of Arctic Ocean sea ice to the recent warming and anomalies in patterns of sea ice circulation. "The near-zero replenishment of the multi-year ice cover, combined with unusual exports of ice out of the Arctic after the summers of 2005 and 2007, have both played significant roles in the loss of Arctic sea ice volume over the ICESat record," says Kwok.

Written by fatih al-farahat in , ,


Not So Windy

Not so fast folks. Here again a sketchy bit of data is tagged and allowed inferences that are at best self serving. Do you really think that had the speed increased that it would not also be seen as positive evidence of global warming?

They have discovered that the present set of data collection devices show a range of variance that may justify investigating the placement of the devices and their wind exposure history and significant cultural changes over the past thirty years. Did the trees also grow?

Slowing wind speed, if real, may explain the increase in tornados for example as convection cells have less chance to dissipate.

In the event we are trying to explain variances in huge macroscopic atmospheric flows that also have shown a decadal scale movement whose drivers are not fully understood. Thus my own musings about atmospheric heat masses in order to maintain some perspective in the real scales applied.

The Northern hemisphere did warm up over at least two decades and maintained heat content for another decade and has now begun cooling. Those three simple assertions appear reasonable and uncontroversial. Applying any of that to the detail is instantly controversial.

Not so windy: Research suggests winds dying down

6/10/2009, 5:26 a.m. ET
SETH BORENSTEIN
The Associated Press

http://www.cleveland.com/printer/printer.ssf?/base/national-3/124463459133860.xml&storylist=washington

(AP) — WASHINGTON - The wind, a favorite power source of the green energy movement, seems to be dying down across the United States. And the cause, ironically, may be global warming-the very problem wind power seeks to address.

The idea that winds may be slowing is still a speculative one, and scientists disagree whether that is happening. But a first-of-its-kind study suggests that average and peak wind speeds have been noticeably slowing since 1973, especially in the Midwest and the East.

"It's a very large effect," said study co-author Eugene Takle, a professor of atmospheric science at Iowa State University. In some places in the Midwest, the trend shows a 10 percent drop or more over a decade. That adds up when the average wind speed in the region is about 10 to 12 miles per hour.
There's been a jump in the number of low or no wind days in the Midwest, said the study's lead author, Sara Pryor, an atmospheric scientist at Indiana University.

Wind measurements plotted out on U.S. maps by Pryor show wind speeds falling mostly along and east of the Mississippi River. Some areas that are banking on wind power, such as west Texas and parts of the Northern Plains, do not show winds slowing nearly as much. Yet, states such as Ohio, Indiana, Michigan, Illinois, Kansas, Virginia, Louisiana, Georgia, northern Maine and western Montana show some of the biggest drop in wind speeds.

"The stations bordering the Great Lakes do seem to have experienced the greatest changes," Pryor said Tuesday. That's probably because there's less ice on the lakes and wind speeds faster across ice than it does over water, she said.

Still, the study, which will be published in August in the peer-reviewed Journal of Geophysical Research, is preliminary. There are enough questions that even the authors say it's too early to know if this is a real trend or not. But it raises a new side effect of global warming that hasn't been looked into before.

The ambiguity of the results is due to changes in wind-measuring instruments over the years, according to Pryor. And while actual measurements found diminished winds, some climate computer models-which are not direct observations-did not, she said.

Yet, a couple of earlier studies also found wind reductions in Australia and Europe, offering more comfort that the U.S. findings are real, Pryor and Takle said.

It also makes sense based on how weather and climate work, Takle said. In global warming, the poles warm more and faster than the rest of the globe, and temperature records, especially in the Arctic, show this. That means the temperature difference between the poles and the equator shrinks and with it the difference in air pressure in the two regions. Differences in barometric pressure are a main driver in strong winds. Lower pressure difference means less wind.

Even so, that information doesn't provide the definitive proof that science requires to connect reduced wind speeds to global warming, the authors said. In climate change science, there is a rigorous and specific method-which looks at all possible causes and charts their specific effects-to attribute an effect to global warming. That should be done eventually with wind, scientists say.

Jeff Freedman, an atmospheric scientist with AWS Truewind, an Albany, N.Y., renewable energy consulting firm, has studied the same topic, but hasn't published in a scientific journal yet. He said his research has found no definitive trend of reduced surface wind speed.

One of the problems Pryor acknowledges with her study is that over many years, changing conditions near wind-measuring devices can skew data. If trees grow or buildings are erected near wind gauges, that could reduce speed measurements.

Several outside experts mostly agree that there are signs that wind speed is decreasing and that global warming is the likely culprit.

The new study "demonstrates, rather conclusively in my mind, that average and peak wind speeds have decreased over the U.S. in recent decades," said Michael Mann, director of the Earth System Science Center at Penn State University.

A naysayer is Gavin Schmidt, a NASA climate scientist in New York who said the results conflict with climate models that show no effect from global warming. He also doubts that any decline in the winds that might be occurring has much of an effect on wind power.

But another expert, Jonathan Miles, of James Madison University, said a 10 percent reduction in wind speeds over a decade "would have an enormous effect on power production."

Pryor said a 10 percent change in peak winds would translate into a 30 percent change in how much energy is reaped. But because the research is in such early stages, she said, "at this point it would be premature to modify wind energy development plans."

Robert Gramlich, policy director at the American Wind Energy Association, said the idea of reduced winds was new to him. He wants to see verification from other studies before he worries too much about it.