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viernes, 10 de octubre de 2014

NASA : NASA Study Finds Earth’s Ocean Abyss Has Not Warmed

Hola amigos: A VUELO DE UN QUINDE EL BLOG., la Agencia Espacial NASA, nos informa que un estudio efectuado se ha comprobado que los abismos de los Océanos no se han calentado; mientras que la parte superior de los océanos del mundo continúan absorber el calor del calentamiento global, las profundidades del océano no se han calentado mensurable en la última década.

Criaturas de aguas profundas, como estas anémonas en un respiradero hidrotermal, aún no están sintiendo el calor del cambio climático global. Aunque la mitad superior del océano continúa calentándose, la mitad inferior no se ha incrementado sensiblemente en la temperatura en la última década.

image shows heat radiating from the Pacific Ocean as imaged by the NASA’s Clouds and the Earth's Radiant Energy System

While the upper part of the world’s oceans continue to absorb heat from global warming, ocean depths have not warmed measurably in the last decade. This image shows heat radiating from the Pacific Ocean as imaged by the NASA’s Clouds and the Earth's Radiant Energy System instrument on the Terra satellite. (Blue regions indicate thick cloud cover.)

Image Credit:

NASA

Deep sea creatures, like these anemones at a hydrothermal vent, are not yet feeling the heat from global climate change. Although the top half of the ocean continues to warm, the bottom half has not increased measurably in temperature in the last decade.

Image Credit:

NERC

The cold waters of Earth’s deep ocean have not warmed measurably since 2005, according to a new NASA study, leaving unsolved the mystery of why global warming appears to have slowed in recent years.

Scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, analyzed satellite and direct ocean temperature data from 2005 to 2013 and found the ocean abyss below 1.24 miles (1,995 meters) has not warmed measurably. Study coauthor Josh Willis of JPL said these findings do not throw suspicion on climate change itself.

"The sea level is still rising," Willis noted. "We're just trying to understand the nitty-gritty details."

In the 21st century, greenhouse gases have continued to accumulate in the atmosphere, just as they did in the 20th century, but global average surface air temperatures have stopped rising in tandem with the gases. The temperature of the top half of the world's oceans -- above the 1.24-mile mark -- is still climbing, but not fast enough to account for the stalled air temperatures.

Many processes on land, air and sea have been invoked to explain what is happening to the "missing" heat. One of the most prominent ideas is that the bottom half of the ocean is taking up the slack, but supporting evidence is slim. This latest study is the first to test the idea using satellite observations, as well as direct temperature measurements of the upper ocean. Scientists have been taking the temperature of the top half of the ocean directly since 2005, using a network of 3,000 floating temperature probes called the Argo array.

"The deep parts of the ocean are harder to measure," said JPL's William Llovel, lead author of the study published Sunday in the journal Nature Climate Change. "The combination of satellite and direct temperature data gives us a glimpse of how much sea level rise is due to deep warming. The answer is -- not much."

The study took advantage of the fact that water expands as it gets warmer. The sea level is rising because of this expansion and the water added by glacier and ice sheet melt.

To arrive at their conclusion, the JPL scientists did a straightforward subtraction calculation, using data for 2005-2013 from the Argo buoys, NASA's Jason-1 and Jason-2 satellites, and the agency’s Gravity Recovery and Climate Experiment (GRACE) satellites. From the total amount of sea level rise, they subtracted the amount of rise from the expansion in the upper ocean, and the amount of rise that came from added meltwater. The remainder represented the amount of sea level rise caused by warming in the deep ocean.

The remainder was essentially zero. Deep ocean warming contributed virtually nothing to sea level rise during this period.

Coauthor Felix Landerer of JPL noted that during the same period warming in the top half of the ocean continued unabated, an unequivocal sign that our planet is heating up. Some recent studies reporting deep-ocean warming were, in fact, referring to the warming in the upper half of the ocean but below the topmost layer, which ends about 0.4 mile (700 meters) down.

Landerer also is a coauthor of another paper in the same journal issue on 1970-2005 ocean warming in the Southern Hemisphere. Before Argo floats were deployed, temperature measurements in the Southern Ocean were spotty, at best. Using satellite measurements and climate simulations of sea level changes around the world, the new study found the global ocean absorbed far more heat in those 35 years than previously thought -- a whopping 24 to 58 percent more than early estimates.

Both papers result from the work of the newly formed NASA Sea Level Change Team, an interdisciplinary group tasked with using NASA satellite data to improve the accuracy and scale of current and future estimates of sea level change. The Southern Hemisphere paper was led by three scientists at Lawrence Livermore National Laboratory in Livermore, California.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

For more information on ocean surface topography from space, visit:

http://sealevel.jpl.nasa.gov

More information on NASA’s GRACE satellites is available at:

http://grace.jpl.nasa.gov

For more information on the Argo array, visit:

http://www.argo.ucsd.edu/index.html

NASA

Guillermo Gonzalo Sánchez Achutegui

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sábado, 6 de septiembre de 2014

NASA : NASA-UCI Study Indicates Loss of West Antarctic Glaciers Appears Unstoppable

Glaciers in West Antarctica’s Amundsen Sea Embayment have “passed the point of no return” according to new research based on three different lines of evidence.

Image Credit:

NASA/Eric Rignot

A new study by researchers at NASA and the University of California, Irvine, finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea.

The study presents multiple lines of evidence, incorporating 40 years of observations that indicate the glaciers in the Amundsen Sea sector of West Antarctica "have passed the point of no return," according to glaciologist and lead author Eric Rignot, of UC Irvine and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. The new study has been accepted for publication in the journal Geophysical Research Letters.

These glaciers already contribute significantly to sea level rise, releasing almost as much ice into the ocean annually as the entire Greenland Ice Sheet. They contain enough ice to raise global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said these findings will require an upward revision to current predictions of sea level rise.

"This sector will be a major contributor to sea level rise in the decades and centuries to come," Rignot said. "A conservative estimate is it could take several centuries for all of the ice to flow into the sea."

Three major lines of evidence point to the glaciers' eventual demise: the changes in their flow speeds, how much of each glacier floats on seawater, and the slope of the terrain they are flowing over and its depth below sea level. In a paper in April, Rignot’s research group discussed the steadily increasing flow speeds of these glaciers over the past 40 years. This new study examines the other two lines of evidence.

The glaciers flow out from land to the ocean, with their leading edges afloat on the seawater. The point on a glacier where it first loses contact with land is called the grounding line. Nearly all glacier melt occurs on the underside of the glacier beyond the grounding line, on the section floating on seawater.

Just as a grounded boat can float again on shallow water if it is made lighter, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by the thinning effects of the glacier stretching out. The Antarctic glaciers studied by Rignot's group have thinned so much they are now floating above places where they used to sit solidly on land, which means their grounding lines are retreating inland.

"The grounding line is buried under a thousand or more meters of ice, so it is incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is," Rignot said. “This analysis is best done using satellite techniques."

The team used radar observations captured between 1992 and 2011 by the European Earth Remote Sensing (ERS-1 and -2) satellites to map the grounding lines' retreat inland. The satellites use a technique called radar interferometry, which enables scientists to measure very precisely -- within less than a quarter of an inch -- how much Earth's surface is moving. Glaciers move horizontally as they flow downstream, but their floating portions also rise and fall vertically with changes in the tides. Rignot and his team mapped how far inland these vertical motions extend to locate the grounding lines.

The accelerating flow speeds and retreating grounding lines reinforce each other. As glaciers flow faster, they stretch out and thin, which reduces their weight and lifts them farther off the bedrock. As the grounding line retreats and more of the glacier becomes waterborne, there's less resistance underneath, so the flow accelerates.

Slowing or stopping these changes requires pinning points -- bumps or hills rising from the glacier bed that snag the ice from underneath. To locate these points, researchers produced a more accurate map of bed elevation that combines ice velocity data from ERS-1 and -2 and ice thickness data from NASA's Operation IceBridge mission and other airborne campaigns. The results confirm no pinning points are present upstream of the present grounding lines in five of the six glaciers. Only Haynes Glacier has major bedrock obstructions upstream, but it drains a small sector and is retreating as rapidly as the other glaciers.

The bedrock topography is another key to the fate of the ice in this basin. All the glacier beds slope deeper below sea level as they extend farther inland. As the glaciers retreat, they cannot escape the reach of the ocean, and the warm water will keep melting them even more rapidly.

The accelerating flow rates, lack of pinning points and sloping bedrock all point to one conclusion, Rignot said.

"The collapse of this sector of West Antarctica appears to be unstoppable," he said. "The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable."

Because of the importance of this part of West Antarctica, NASA's Operation IceBridge will continue to monitor its evolution closely during this year's Antarctica deployment, which begins in October. IceBridge uses a specialized fleet of research aircraft and the most sophisticated suite of science instruments ever assembled to characterize changes in thickness of glaciers, ice sheets and sea ice.

For additional images and video related to this new finding, visit:

http://go.nasa.gov/1m6YZSf

For additional information on the West Antarctic Ice Sheet and its potential contribution to sea level rise, visit:

http://go.nasa.gov/1oIfSlO

For more information on Operation IceBridge, visit:

http://www.nasa.gov/icebridge

The California Institute of Technology in Pasadena manages JPL for NASA.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

NASA

Guillermo Gonzalo Sánchez Achutegui

Download this video in HD formats from NASA Goddard's Scientific Visualization Studio

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viernes, 15 de agosto de 2014

NASA : NASA to Investigate Climate Impacts of Arctic Sea Ice Loss

Youtube Override:

Image Credit:

NASA's Goddard Space Flight Center/J. Beck

Feature Link:

A new NASA field campaign will begin flights over the Arctic this summer to study the effect of sea ice retreat on Arctic climate. The Arctic Radiation IceBridge Sea and Ice Experiment (ARISE) will conduct research flights Aug. 28 through Oct. 1, covering the peak of summer sea ice melt.

ARISE is NASA's first Arctic airborne campaign designed to take simultaneous measurements of ice, clouds and the levels of incoming and outgoing radiation, the balance of which determines the degree of climate warming. The campaign team will fly aboard NASA’s C-130 aircraft from Thule Air Base in northern Greenland the first week and from Eielson Air Force Base near Fairbanks, Alaska, through the remainder of the campaign.

In recent years the Arctic has experienced increased summer sea ice loss. Scientists expect the exposure of more open water to sunlight could enhance warming in the region and cause the release of more moisture to the atmosphere. Additional moisture could affect cloud formation and the exchange of heat from Earth’s surface to space. Researchers are grappling with how these changes in the Arctic affect global climate.

NASA’s C-130 aircraft will carry scientists over the Arctic starting this month from northern Greenland and Fairbanks, Alaska.

Image Credit:

NASA

"A wild card in what's happening in the Arctic is clouds and how changes in clouds, due to changing sea-ice conditions, enhance or offset warming," said Bill Smith, ARISE principal investigator at NASA's Langley Research Center in Hampton, Virginia.

ARISE was planned over the last year to take advantage of NASA’s existing capabilities for gathering data about ongoing changes in the Arctic. Satellites provided some information about clouds and the energy balance in the Arctic, but the multiple instruments flown during ARISE should provide further insight.

"The clouds and surface conditions over the Arctic as we observe them from satellites are very complex," Smith said. "We need more information to understand how to better interpret the satellite measurements, and an aircraft can help with that."

The array of instruments on ARISE should help scientists better observe how sea ice loss is affecting Arctic cloud formation and therefore the balance of incoming and outgoing radiation. Low-level clouds typically reflect more sunlight and offset warming, while higher clouds are typically less reflective and act to trap more heat in the atmosphere.

“It’s a complex business, but it depends on a lot of things we can, in fact, measure,” said Hal Maring, program manager for radiation sciences in the Earth Science Division at NASA Headquarters in Washington.

ARISE researchers will fly survey missions that target different cloud types and surface conditions, such as open water, land ice and sea ice. The missions will be timed to fly under the orbit paths of key satellite instruments, such as the Clouds and the Earth’s Radiant Energy Systems (CERES) instruments on multiple NASA satellites. Each morning, mission planners will look at satellite timings and weather forecasts to design flight plans that meet the most objectives of the campaign.

The NASA C-130, based at the Wallops Flight Facility in Virginia, will carry instruments that measure solar (incoming) and infrared (outgoing) radiation, ice surface elevation and cloud properties such as cloud particle size. This will be the first time that many of these instruments, including the mission's laser altimeter, have flown together.

The ARISE campaign is a joint effort of the Radiation Sciences, Cryospheric Sciences and Airborne Sciences programs of the Earth Science Division in NASA's Science Mission Directorate in Washington.

To learn more about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

NASA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@Hotmail.com

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viernes, 4 de abril de 2014

NASA : NASA’s OCO-2 Brings Sharp New Focus on Global Carbon

Animated GIF Override:

This animation shows the Orbiting Carbon Observatory-2, the first NASA spacecraft dedicated to studying carbon dioxide in Earth’s atmosphere.

Image Credit:

NASA/JPL-Caltech

Five new NASA Earth science missions will join Landsat 8 in space this year to expand our understanding of Earth’s changing climate and environment.

Feature Link:

"Earth Right Now" website

Simply by breathing, humans have played a small part in the planet-wide balancing act called the carbon cycle throughout our existence. However, in the last few hundred years, we have taken a larger role. Our activities, such as fossil fuel burning and deforestation, are pushing the cycle out of its natural balance, adding more and more carbon dioxide to the atmosphere.

Natural processes are working hard to keep the carbon cycle in balance by absorbing about half of our carbon emissions, limiting the extent of climate change. There's a lot we don't know about these processes, including where they are occurring and how they might change as the climate warms. To understand and prepare for the carbon cycle of the future, we have an urgent need to find out.

In July 2014, NASA will launch the Orbiting Carbon Observatory-2 (OCO-2) to study the fate of carbon dioxide worldwide. "Right now, the land and the ocean are taking up almost half of the carbon dioxide we add to the atmosphere by burning fossil fuels, but the future is fundamentally unknown," said Paul Wennberg, a professor of atmospheric chemistry at the California Institute of Technology in Pasadena. "OCO-2 is a key to getting answers." The mission has been developed and is managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Carbon dioxide is both one of the best measured greenhouse gases and one of the least measured. The emissions that remain in the atmosphere become evenly distributed around the globe in a matter of months. As a result, the average atmospheric concentration can be monitored well by existing ground stations (about 160 worldwide). The other half of our emissions -- the half that is being absorbed through natural processes into the land or the ocean -- is not evenly distributed. To understand where that carbon dioxide is going, we need precise, comprehensive, ongoing data about carbon dioxide absorption and emission by forests, the ocean and many other regions. For some of these regions, we have far too few observations.

"A research ship moves about the speed of a 10-speed bicycle," said Scott Doney, director of the Ocean and Climate Change Institute at the Woods Hole Oceanographic Institution, Woods Hole, Mass. "Think about the size of the ocean. There's only so much research you can do at the speed of a bicycle." Oceanographers have made up some of the observational deficit by contracting with shipping lines to gather data along commercial routes. But there's little shipping in the Southern Ocean, and Doney said that's a region of high concern. "With warming, we expect big changes. The winds are changing there, and carbon dioxide uptake may change too."

On land, Earth's great forests might be the least understood areas. In northern Siberia, a region with no permanent settlements and few roads, there are only six year-round monitoring sites across seven time zones. Forests remove carbon from the air during photosynthesis and store it in wood and roots, making these forests what scientists call carbon sinks. But droughts and wildfires can turn forests into carbon sources, releasing the stored carbon back into the atmosphere. We don't know when and how often forests cross the line from sink to source.

OCO-2 will not be the first satellite to measure carbon dioxide, but it's the first with the observational strategy, precision, resolution and coverage needed to answer these questions about these little-monitored regions, according to Ralph Basilio, OCO-2 project manager at JPL.

OCO-2's scientific instrument uses spectrometers, which split sunlight into a spectrum of component colors, or wavelengths. Like all other molecules, carbon dioxide molecules absorb only certain colors of light, producing a unique pattern of dark features in the spectrum. The intensity of the dark features increases as the number of carbon dioxide molecules increases in the air that the spectrometer is looking through.

Carbon dioxide concentrations in the atmosphere are measured in parts per million, the number of molecules of carbon dioxide there are in every million molecules of air. That number is currently around 400. OCO-2's spectrometers can detect changes of one or two carbon dioxide molecules out of the 400 -- an unprecedented level of precision, and one that scientists think will be adequate to detect changes in natural sources and sinks, once enough measurements have been collected.

OCO-2 will collect 24 measurements a second over Earth’s sunlit hemisphere, totaling more than a million measurements each day. Fewer than 20 percent of these measurements will be sufficiently cloud-free to allow an accurate estimate of carbon dioxide, but that number will still yield 100 to 200 times as many measurements as the currently observing Japanese Greenhouse gases Observing SATellite (GOSAT) mission. The measurements will be used as input for global atmospheric models. Combined with data on winds and other conditions, the OCO-2 data will allow modelers to better locate carbon sources and sinks at regional scales -- areas the size of France or Texas.

"With atmospheric carbon dioxide at unprecedented levels, our sense of urgency has only increased,” said Basilio. “What will happen if we keep emitting carbon dioxide at the same rate? The ultimate goal for OCO-2 is to provide data so that organizations and individuals throughout the world can make better-informed decisions about carbon."

For more information about OCO-2, visit:

https://oco.jpl.nasa.gov

OCO-2 is one of five new NASA missions launching in 2014. NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to see better how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

NASA

Guillermo Gonzalo Sánchez Achutegui