Robot Goes to Work While Crew Prepares for Spacewalks

Robotics and spacewalk preparations took center stage Tuesday aboard the International Space Station as the Expedition 24 crew orbited above the Earth.

Dextre, an agile, two-armed extension for the station’s Canadarm2 robotic arm, continues its debut task to replace a failed Remote Power Control Module (RPCM) from a truss segment on the station’s port side. On Tuesday flight controllers in Houston began conducting a “dress rehearsal” of the actual replacement as they commanded Dextre to partially remove and reinstall an RPCM on the P1 truss. After Dextre successfully completes the test, Mission Control plans to swap the failed RPCM with a spare from the P3 truss Wednesday.

Meanwhile the Expedition 24 crew continued its own preparations to venture outside the station for an upcoming pair of spacewalks.

Image above: The Soyuz TMA-19 spacecraft (partially out of frame in the foreground), docked to the Rassvet Mini-Research Module 1, and the ISS Progress 37 resupply vehicle, docked to the Pirs Docking Compartment, are featured in this image. Credit: NASA

Cosmonauts Fyodor Yurchikhin and Mikhail Kornienko, both flight engineers, prepared the cooling loops of the Russian Orlan spacesuits they will wear during a six-hour spacewalk set to begin the evening of July 26. The pair will install Kurs automated rendezvous equipment on the exterior of the recently delivered Rassvet module to facilitate future dockings with Russian spacecraft.

Flight Engineers Doug Wheelock and Tracy Caldwell Dyson continued preparations for their Aug. 5 spacewalk as they each conducted a session of onboard training for Simplified Aid for EVA Rescue, or SAFER. Should a spacewalker become untethered during a spacewalk and begin floating away, the small nitrogen-jet thrusters of SAFER could help the astronaut get back to the station.

Shannon Walker, also a station flight engineer, assisted with the American spacewalk preparations as she inspected safety and waist tethers for structural integrity and reviewed spacewalk procedures.

The Expedition 24 crew also tackled a number of science investigations Tuesday. Commander Alexander Skvortsov spent part of his day working with a Russian experiment known as Russalka, which involves using a camera equipped with an ultraviolet filter to collect measurements of methane and carbon dioxide in the Earth’s atmosphere.

Wheelock prepared the Solution Crystallization Observation Facility for a Japanese study of facet-like crystallization. The results of this experiment may provide valuable data on creating high quality materials for industrial use such as superconducting magnets.

The Americans also continued maintenance work on the Oxygen Generation System, flushing the components that allow liquid to flow through the system so that oxygen can be extracted from recycled water to provide air for the crew to breathe.

Later, Walker assisted Wheelock with the latest session of Kids In Micro-Gravity!, an experiment that gives students a hands-on opportunity to design a demonstration that can be performed both in the classroom and aboard the station. Tuesday’s activity, a look at whether blowing across the tops of bottles filled with different amounts of water will create the same tones in space as on Earth, was developed by fifth grade students at Vaughan Elementary in Powder Springs, Ga.

Researchers can learn more about opportunities to develop and fly science experiments on the International Space Station (ISS) at the NASA ISS Research Academy Aug. 3-5 in League City, Texas.

For more information visit http://www.nasa.gov/mission_pages/station/main/index.html

NASA Awards Launch Services Contract for OCO-2 Mission

PASADENA, Calif. – NASA has selected Orbital Sciences Corp. of Dulles, Va., to launch the Orbiting Carbon Observatory-2 (OCO-2) mission. The spacecraft will fly in February 2013 aboard a Taurus XL 3110 rocket launched from Vandenberg Air Force Base in California.

The total cost of the OCO-2 launch services is approximately $70 million. The estimated cost includes the task ordered launch service for a Taurus XL 3110 rocket, plus additional services under other contracts for payload processing, OCO-2 mission-unique support, launch vehicle integration, and tracking, data and telemetry support.

This is an artist’s concept of the Orbiting Carbon Observatory. Image credit: NASA/JPL

OCO-2 is NASA's first mission dedicated to studying atmospheric carbon dioxide. Carbon dioxide is the leading human-produced greenhouse gas driving changes in Earth's climate. OCO-2 will provide the first complete picture of human and natural carbon dioxide sources and "sinks," the places where the gas is pulled out of the atmosphere and stored. It will map the global geographic distribution of these sources and sinks and study their changes over time. The OCO-2 spacecraft will replace OCO-1, lost during a launch vehicle failure in 2009.

The OCO-2 project is managed by the Jet Propulsion Laboratory in Pasadena, Calif. NASA's Launch Services Program at the Kennedy Space Center in Florida is responsible for launch vehicle program management of the Taurus XL 3110 rocket.

For more information about NASA and agency missions, visit: http://www.nasa.gov . For more on OCO-2, visit: http://oco.jpl.nasa.gov/ .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/mission_pages/oco/news/oco20100622.html

Crew Does Maintenance, Science; Soyuz Launch Date Approaches

The International Space Station’s Expedition 24 crew began the week Monday with a variety of science experiments.

Flight Engineer Tracy Caldwell Dyson was scheduled to reinstall an old pump into the U.S. segment’s oxygen generation system, in an effort to coax it back into action to support the increase of the crew to six people which will begin Thursday.

Flight Engineer Mikhail Kornienko restarted the Elektron oxygen generation system in the Russian segment over the weekend.

Commander Alexander Skvortsov conducted an observation with the Rusalka experiment, which is a test of procedures for remote determination of methane and carbon dioxide content in the Earth’s atmosphere.

Skvortsov also assisted Kornienko in a session with the Russian Pilot-M experiment. Pilot-M tests piloting skill in simulations on a laptop under stopwatch control and studies the response of cosmonauts to the effects of stress factors in flight.

Image above: The Soyuz TMA-19 spacecraft is rolled out by train to the launch pad at the Baikonur Cosmodrome, Kazakhstan, Sunday, June 13, 2010. Credit: NASA/Carla Cioffi

Caldwell Dyson took photographs of the moon for the Japan Aerospace Exploration Agency educational program known as ISS Moon Score. The purpose of this program is to create a musical score using photos of the moon taken at different times in the lunar cycle, while the crew is floating naturally in the microgravity environment.

Following the rollout of their Soyuz TMA-19 spacecraft to the launch pad Sunday, Expedition 24 Flight Engineers Doug Wheelock, Shannon Walker and Fyodor Yurchikhin met Monday with the Russian State Commission of top space officials and conducted their final pre-launch Crew News Conference at their Cosmonaut Hotel crew quarters. Everything is on track for launch Tuesday at 5:35 p.m. EDT. The new crew members are slated to dock to the station’s Zvezda service module Thursday at 6:25 p.m.

For more information visit http://www.nasa.gov/mission_pages/station/main/index.html

NASA Scientist Nadine Unger Discusses Which Sectors of the Economy Impact the Climate

Nadine Unger, a climatologist with NASA’s Goddard Institute for Space Studies in New York City, spoke with NASA's Earth Science News Team about her recent study that analyzed how different human activities impact climate. The study appeared in the Proceedings of the National Academy of Sciences in February.

NASA's Earth Science News Team: Your research suggests that the climate science community ought to shift its focus from looking at the impacts of individual chemicals to economic sectors. Why?

Nadine Unger: There's nothing "wrong" with dividing climate impacts up by chemical species, but it's not particularly useful for policy makers. They need to know which human activities are impacting the climate and what the effect will be if they attempt to curb emissions from a particular sector. Also, there's a great deal of complexity in our emissions that they need to be mindful of if we want to mitigate climate change efficiently.

NASA: What sort of complexity?

Nadine Unger: Some sectors of the economy produce a mixture of pollutants -- particularly aerosols -- that cause cooling rather than warming in the short term. Since warming can accelerate as we remove aerosols, we've been inadvertently geoengineering for decades with aerosol emissions.

Take the heavy industry and shipping sectors, for example. These sectors burn a great deal of coal and bunker fuel, which releases carbon dioxide, which causes greenhouse warming. But they also release sulfates, which cause cooling by blocking incoming radiation from the sun and by changing clouds to make them brighter and longer-lived. In the short term, the cooling from sulfates actually outweighs the warming from carbon dioxide, meaning the net impact of the shipping and heavy industry sectors today is to cool climate.

Compare that to cars and trucks, which emit almost no sulfates but a great deal of carbon dioxide, black carbon, and ozone -- all of which cause warming and happen to be very bad for human health. Cutting transportation emissions would be unambiguously good for the climate in the short term, while cutting heavy industry emissions would have less of an impact right now.

NASA: You keep mentioning "short-term" impacts. Could the climate impacts of some sectors of the economy change over longer time periods?

Nadine Unger: Yes. Greenhouse gases have a much longer lifespan -- or residence time -- in the atmosphere than aerosols, which typically rain out after a few days or weeks. This means that the impact of greenhouse gases can accumulate and intensify over time, while the aerosol effects become comparatively less important on longer time scales due to the accumulation of carbon dioxide.

NASA's Goddard Institute for Space Studies scientist Nadine Unger. Credit: NASA's Goddard Institute for Space Studies

NASA: You've mentioned industry, shipping and on-road transportation. What other sectors of the economy did you analyze?

Nadine Unger: Aviation, household fossil fuels, railroads, household biofuels (mainly wood and dung used for home cooking and heating), animal husbandry, the electric power sector, waste and landfills, agriculture, biomass burning...

NASA: What is biomass burning?

Nadine Unger: Mainly tropical forest fires, deforestation and savannah and shrub fires. We also looked at agricultural waste burning, which relates to seasonal clearing of the fields common in many countries in Africa and South America.

NASA: So, does this mean that pollution from industry and biomass burning is good for the climate?

Nadine Unger: No, not at all. Both of those sectors contribute to warming over the long term, so we'll have no choice but to reduce our emissions over time. But these sectors do mask warming from greenhouses gases in the short term. Just because an activity causes cooling in the short-term does not mean that it is ‘good’ for the climate. The emissions might disturb other aspects of the climate system including the amount of rainfall in a region and therefore the water supply to humans.

NASA: Where did you get all the information about emissions?

Nadine Unger: We used emission inventories assembled by colleagues. For instance, a colleague from the University of Illinois -- Tami Bond -- has some of the best information on some types of aerosols, such as black carbon.

NASA: But how can you estimate the impacts of emissions that haven't happened yet?

Nadine Unger: We used a computer model at GISS to look at future at climate impacts if we continued emitting pollutants at today's rate. Using this approach, we looked specifically at two snapshots in time: 2020 and 2100.

NASA: What can we do if we want to minimize climate change in the near term?

Nadine Unger: Well, our analysis suggests that on-the-road transportation and household biofuels are very attractive sectors to target. We can reduce human warming impacts most rapidly by tackling emissions from these sectors. In order to protect climate in the longer term, emissions from power and industry must be reduced.

NASA: Are there any uncertainties in your results?

Nadine Unger: There are. There's a large amount of uncertainty about how aerosols affect climate, especially through the indirect effects on clouds. Hopefully, NASA's Glory mission will help reduce the uncertainties associated with aerosols.

NASA: What direction do you see your research going next?

Nadine Unger: Our focus has been on global climate so far, but in future work we'll assess regional climate impacts, as well as other disturbances to the climate system, such as effects on the water supply and land ecosystems.

In addition, we plan to investigate many of the sectors in greater detail. In the power sector, for example, we might look specifically at power stations that operate with coal or natural gas. And in the on-road transportation sector, we might break out heavy- from light-duty vehicles.

Finally, we're planning to partner with environmental economists to determine the damage costs of emissions from all the sectors due to both climate and air quality impacts, results that we can use to develop alternative mitigation scenarios.

For more information visit http://www.nasa.gov/topics/earth/features/unger-qa.html

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Road Transportation Emerges as Key Driver of Warming in New Analysis from NASA

For decades, climatologists have studied the gases and particles that have potential to alter Earth's climate. They have discovered and described certain airborne chemicals that can trap incoming sunlight and warm the climate, while others cool the planet by blocking the Sun's rays.

Now a new study led by Nadine Unger of NASA's Goddard Institute for Space Studies (GISS) in New York City offers a more intuitive way to understand what's changing the Earth's climate. Rather than analyzing impacts by chemical species, scientists have analyzed the climate impacts by different economic sectors.

Each part of the economy, such as ground transportation or agriculture, emits a unique portfolio of gases and aerosols that affect the climate in different ways and on different timescales.

"We wanted to provide the information in a way that would be more helpful for policy makers," Unger said. "This approach will make it easier to identify sectors for which emission reductions will be most beneficial for climate and those which may produce unintended consequences."

Motor vehicles give off only minimal amounts of sulfates and nitrates, both pollutants that cool climate, though they produce significant amounts of pollutants that warm climate such as carbon dioxide, black carbon, and ozone. Credit: NASA's Langley Research Center

In a paper published online on Feb. 3 by the Proceedings of the National Academy of Sciences, Unger and colleagues described how they used a climate model to estimate the impact of 13 sectors of the economy from 2000 to 2100. They based their calculations on real-world inventories of emissions collected by scientists around the world, and they assumed that those emissions would stay relatively constant in the future.

Snapshots of the Future

In their analysis, motor vehicles emerged as the greatest contributor to atmospheric warming now and in the near term. Cars, buses, and trucks release pollutants and greenhouse gases that promote warming, while emitting few aerosols that counteract it.

The researchers found that the burning of household biofuels -- primarily wood and animal dung for home heating and cooking -- contribute the second most warming. And raising livestock, particularly methane-producing cattle, contribute the third most.

On the other end of the spectrum, the industrial sector releases such a high proportion of sulfates and other cooling aerosols that it actually contributes a significant amount of cooling to the system. And biomass burning -- which occurs mainly as a result of tropical forest fires, deforestation, savannah and shrub fires -- emits large amounts of organic carbon particles that block solar radiation.

The new analysis offers policy makers and the public a far more detailed and comprehensive understanding of how to mitigate climate change most effectively, Unger and colleagues assert. "Targeting on-road transportation is a win-win-win," she said. "It's good for the climate in the short term and long term, and it's good for our health."

The on-road transportation sector releases significant amounts of carbon dioxide, black carbon, and ozone—all substances that cause warming. In contrast, the industrial sector releases many of the same gases, but it also tends to emit sulfates and other aerosols that cause cooling by reflecting light and altering clouds. Credit: NASA GISS/Unger

Due to the health problems caused by aerosols, many developed countries have been reducing aerosol emissions by industry. But such efforts are also eliminating some of the cooling effect of such pollution, eliminating a form of inadvertent geoengineering that has likely counteracted global warming in recent decades.

"Warming should accelerate as we continue to remove the aerosols," said Unger. "We have no choice but to remove the aerosol particulate pollution to protect human and ecosystem health. That means we'll need to work even harder to reduce greenhouse gases and warming pollutants."

By the year 2100, Unger's projections suggest that the impact of the various sectors will change significantly. By 2050, electric power generation overtakes road transportation as the biggest promoter of warming. The industrial sector likewise jumps from the smallest contribution in 2020 to the third largest by 2100.

"The differences are because the impacts of greenhouse gases accumulate and intensify over time, and because they persist in the atmosphere for such long periods," said Unger. "In contrast, aerosols rain out after a few days and can only have a short-term impact."

Factoring in Clouds

For each sector of the economy, Unger's team analyzed the effects of a wide range of chemical species, including carbon dioxide, nitrous oxide, methane, organic carbon, black carbon, nitrate, sulfate, and ozone.

Unger's model finds that in 2020 (left), transportation, household biofuels and animal husbandry will have the greatest warming impact on the climate, while the shipping, biomass burning, and industrial sectors will have a cooling impact. By 2100 (right), the model finds that the power and industrial sector will become strongly warming as carbon dioxide accumulates. Credit: NASA GISS/Unger

The team also considered how emissions from each part of the economy can impact clouds, which have an indirect effect on climate, explained Surabi Menon, a coauthor of the paper and scientist at the Lawrence Berkeley National Laboratory in Berkeley, Calif.

Some aerosols, particularly sulfates and organic carbon, can make clouds brighter and cause them to last longer, producing a cooling effect. At the same time, one type of aerosol called black carbon, or soot, actually absorbs incoming solar radiation, heats the atmosphere, and drives the evaporation of low-level clouds. This process, called the semi-direct aerosol effect, has a warming impact.

Unger's analysis is one of the first of its kind to incorporate the multiple effects that aerosol particles can have on clouds, which affect the climate indirectly. Credit: NASA's Johnson Space Center

The new analysis shows that emissions from the power, biomass burning, and industrial sectors of the economy promote aerosol-cloud interactions that exert a powerful cooling effect, while on-road transportation and household biofuels exacerbate cloud-related warming.

More research on the effects of aerosols is still needed, Unger cautions. "Although our estimates of the aerosol forcing are consistent with those listed by the International Panel on Climate Change, a significant amount of uncertainty remains."

Related Links

Related Q & A with Nadine Unger
› http://www.nasa.gov/topics/earth/features/unger-qa.html

Nadine Unger Bio
› http://giss.nasa.gov/staff/nunger.html

Attribution of Climate Forcing to Economic Sectors
› http://pnas.org/content/early/2010/02/02/0906548107.abstract

Nadine Unger Bio
› http://giss.nasa.gov/staff/nunger.html

Other Research by Nadine Unger
› http://pubs.giss.nasa.gov/authors/nunger.html

Clean the Air, Heat the Planet
› http://sciencemag.org/cgi/content/short/326/5953/672

For more information visit http://www.nasa.gov/topics/earth/features/road-transportation.html

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Endeavour to Deliver a Room With a View

The International Space Station has been moving steadily closer to completion for the past several years. But what house is complete without a utility room, a gym and a picture window?

During the STS-130 mission, space shuttle Endeavour will deliver the Tranquility node and its cupola, a dome-shaped extension from Tranquility made up of seven windows. They will be the last major U.S. modules to be added to the space station, and together they’ll help clear out premium workspace in other areas of the station – as well as offer a window on the world.

At 15 feet wide and 23 feet long, the Tranquility node will provide a centralized home for the station’s environmental control equipment – one of the systems that remove carbon dioxide from the station’s air, one of the station’s bathrooms and the equipment that converts urine into drinkable water, all of which is currently taking up space in the Destiny laboratory. And there’s enough room left over to house the station’s new treadmill and its microgravity equivalent of a weight machine, moving it out of the Unity node where it’s in the way whenever spacewalk preparations are going on inside the adjacent Quest airlock.

A computer generated scene gives the perspective of a crew member looking through the Cupola on the International Space Station. Photo Credit: NASA

“It gives us a much needed addition to the house, so to speak,” said Bob Dempsey, lead space station flight director for the mission. “We’re getting to the point where we’re really cramped for space. You might be surprised at that, considering we’re essentially the volume of a 747 and we’ve been adding modules for the last couple of years. You might think we’d be sitting around in a big empty house. But no – every inch is really getting packed up there.”

STS-130 Commander George Zamka put it another way.

“It’s like exercising in the office,” he said. “This will be a more logical organization, more focused.”

Though the node has an intensely practical function, there are still fanciful aspects to Tranquility. For one, its name, which was chosen with the help of a naming contest on NASA.gov.

“It harkens back to the Sea of Tranquility, where humans made their very first tentative landing on the moon,” Zamka said. “They were only there for a few hours, and it was at the very limits of what human beings could do. From that beginning, we’re now putting up a node that will house the majority of the life support equipment for the station, where we’re going to have a permanent presence in space.”

But everyone agrees that the real scope for the imagination will be provided by Tranquility’s 6.5-by-5-foot annex: the cupola. Its true purpose will be to provide a true view of robotics operations on the station’s exterior – such as those that will be required when the next module, the Russian Rassvet, is added during STS-132 – and in that it will be invaluable.

A slightly high-angle view of the International Space Station's Cupola in the Alenia Spazio clean room in Turin, Italy. Photo Credit: NASA

“Out the window is the truth,” Zamka said. “The video views that we use now, you’re trying to stick together and have a mental image of where things are. When you look out the window, you don’t have to imagine. It’s all right there for you.”

But there’s no question that many people – including Zamka – are looking forward to looking out of it for other views.

“Just the idea of providing this great view of the station and the world beneath us is going to be pretty great,” he said. “That’s not what it’s for, but it will be spectacular.”

The cupola will be like a mini control tower sticking out from the Tranquility node, as opposed to the other station windows, which are flush with the station’s exterior. Its seven windows – one in the center and six around the sides – will provide the only views of the outside of the station from the inside, in particular the Russian and Japanese sections. And with the station just about finished, there’s more to see out there than ever.

So, Zamka said, in addition to the robotic operations and Earth views it will provide, it will also give us a good look at some of the space shuttle fleet’s finest handiwork as the program comes to an end. And that provides its own cause for reflection.

A low angle view shows the interior of the International Space Station's Cupola in the Alenia Spazio clean room in Turin, Italy. Photo Credit: NASA

“We’ve come a long way in human spaceflight because of the shuttle’s capability,” he said. “We’ve launched and retrieved satellites, we’ve done medical research and now we’ve built this huge space station. We’re almost to the point of passing the baton from the space shuttle to the space station in terms of what our human spaceflight experience will be now.”

Kwatsi Alibaruho, lead STS-130 space shuttle flight director, said that even with so much left to do in the program’s final five flights, he was making it a point to spend some time thinking about the subject.

“It’s very easy to get into a routine, to lose oneself in the hustle and bustle of trying to get the work done,” Alibaruho said. “But the shuttle is a unique spacecraft. I find myself thinking a lot about how I’m going to describe this time to my son when he’s old enough to understand. There has never been an operational spacecraft like it before and all indications are that it will be some time before there will be one like it again. I find myself really appreciative of the opportunity I’ve had to serve in this capacity.”

For more information visit http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts130/room_with_a_view.html

Quiet Sun Means Cooling of Earth's Upper Atmosphere

New measurements from a NASA satellite show a dramatic cooling in the upper atmosphere that correlates with the declining phase of the current solar cycle. For the first time, researchers can show a timely link between the Sun and the climate of Earth’s thermosphere, the region above 100 km, an essential step in making accurate predictions of climate change in the high atmosphere.

Data from the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) mission are being used to understand the climate of the upper atmosphere. Credit: NASA

Scientists from NASA's Langley Research Center and Hampton University in Hampton, Va., and the National Center for Atmospheric Research in Boulder, Colo., presented these results at the fall meeting of the American Geophysical Union in San Francisco from Dec. 14 to 18.

Earth's thermosphere and mesosphere have been the least explored regions of the atmosphere. The NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission was developed to explore the Earth’s atmosphere above 60 km altitude and was launched in December 2001. One of four instruments on the TIMED mission, the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, was specifically designed to measure the energy budget of the mesosphere and lower thermosphere. The SABER dataset now covers eight years of data and has already provided some basic insight into the heat budget of the thermosphere on a variety of timescales.

The extent of current solar minimum conditions has created a unique situation for recent SABER datasets, explains Stan Solomon, acting director of the High Altitude Observatory, National Center for Atmospheric Research in Boulder, Colo. The end of solar cycle 23 has offered an opportunity to study the radiative cooling in the thermosphere under exceptionally quiescent conditions.

"The Sun is in a very unusual period," said Marty Mlynczak, SABER associate principal investigator and senior research scientist at NASA Langley. "The Earth’s thermosphere is responding remarkably — up to an order of magnitude decrease in infrared emission/radiative cooling by some molecules."

Energy emitted by the upper atmosphere as infrared (IR) radiation in 2002 (top) and 2008 (bottom) -- In this SABER plot, Nitric Oxide (NO) is the IR emitter. Researchers are building a climate record of the thermosphere using this data. Credit: NASA

The TIMED measurements show a decrease in the amount of ultraviolet radiation emitted by the Sun. In addition, the amount of infrared radiation emitted from the upper atmosphere by nitric oxide molecules has decreased by nearly a factor of 10 since early 2002. These observations imply that the upper atmosphere has cooled substantially since then. The research team expects the atmosphere to heat up again as solar activity starts to pick up in the next year.

While this warming has no implications for climate change in the troposphere, a fundamental prediction of climate change theory is that the upper atmosphere will cool in response to increasing carbon dioxide. As the atmosphere cools the density will increase, which ultimately may impact satellite operations through increased drag over time.

The SABER dataset is the first global, long-term, and continuous record of the Nitric oxide (NO) and Carbon dioxide (CO2) emissions from the thermosphere.

"We suggest that the dataset of radiative cooling of the thermosphere by NO and CO2 constitutes a first climate data record for the thermosphere," says Mlynczak.

The TIMED data provide a climate record for validation of upper atmosphere climate models, which is an essential step in making accurate predictions of climate change in the high atmosphere. SABER provides the first long-term measurements of natural variability in key terms of the upper atmosphere climate.

Energy emitted by the upper atmosphere as infrared (IR) radiation in 2002 (top) and 2008 (bottom) -- In this SABER plot, Carbon Dioxide (CO2) is the IR emitter. Researchers are building a climate record of the thermosphere using this data. Credit: NASA

"A fundamental prediction of climate change theory is that upper atmosphere will cool in response to greenhouse gases in the troposphere," says Mlynczak. "Scientists need to validate that theory. This climate record of the upper atmosphere is our first chance to have the other side of the equation."

James Russell III, SABER principal investigator and co-director of the Center for Atmospheric Sciences at Hampton University in Hampton, Va., agrees adding, "The atmosphere is a coupled system. If you pick up one end of the stick, you automatically pick up the other – they're intrinsically linked. To be as accurate as possible, scientists have to understand global change throughout the atmosphere."

As the TIMED mission continues, these data derived from SABER will become important in assessing long term atmospheric changes due to the increase of carbon dioxide in the atmosphere.

TIMED is the first mission in the Solar Terrestrial Probes Program within the Heliophysics Division in NASA's Science Mission Directorate in Washington.

Related Links:
› TIMED Mission
› SABER Instrument

Katie Lorentz
NASA's Langley Research Center

For more information visit http://www.nasa.gov/topics/earth/features/coolingthermosphere.html

NASA Calculates a Carbon Budget for the State of California

While world organizations struggle to find a benchmark and tracking standards for greenhouse gas (GHG) emissions, NASA has been supporting California’s new carbon emissions inventory report, using its satellite imaging data and computer models of the state’s natural ecosystems.

Researchers report that in 2004, the state’s natural ecosystems absorbed as much carbon dioxide from the atmosphere as fossil fuel carbons emitted into the atmosphere. They also discovered that during periods of above normal rainfall, ecosystems trapped significant amounts of carbon dioxide from the atmosphere in forests and soils. For these reasons, researchers suggest the ecosystems should be more extensively protected and conserved, and their emissions be monitored as closely as fossil fuel sources of GHG emissions. The results, based largely on a computer model called the NASA-Carnegie Ames Stanford Approach (CASA), will be presented this morning at the 2009 American Geophysical Union Fall meeting in San Francisco.

"One way to facilitate emissions reductions is by using regional and national carbon budgets," explained Christopher Potter, senior research scientist at NASA Ames Research Center, Moffett Field, Calif., and author of this study. "California’s growing population and demand for all forms of energy make it essential to maintain an accurate and complete accounting of the state’s greenhouse emissions inventory," Potter added.

California’s population is more than 10 percent of the total population in the United States, and produces 13 percent of the U.S. gross domestic product, according to 2000 U.S. Census Bureau data. Because of its large population, the state also contributes significantly to global GHG emissions. If California was a country, it would rank among the top 20 national GHG emitters worldwide.

The carbon budget of a region is determined by the amounts of carbon dioxide and methane gases absorbed or released by “green” vegetative ground cover, as observed by NASA satellites. These fluctuations are important to quantify, because they originate from both natural and anthropogenic processes.

In California, the main sources of carbon dioxide emissions are energy consumption in commercial, residential, industrial, and transportation sectors, production of cement and lime, and waste treatment. The main sources of methane emission are derived from landfills and agricultural (principally livestock-based) systems.

Scientists believe that California’s carbon budget is of special interest because the state may represent a U.S. national carbon budget; both have diversified lands, similar consumption of natural resources, and urban lifestyles. Other similarities include a mix of fossil fuel emissions, alternative energy sources, and ecosystem sinks.

Each year, California is required by law to compile a new carbon emission inventory, which is conducted by the California Energy Commission and California’s Air Resources Board. To refine the state’s emission inventory, NASA was asked to provide NASA satellite imaging data and carbon models. To locate the largest ecosystem sources and carbon sinks in California, scientists used the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the NASA Terra satellite. The vegetation “greenness” data from the MODIS sensor was directly downloaded into the CASA ecosystem simulation model. Scientists used the data to estimate monthly variations in the accumulated biomass of wood and other plant materials, such as the accumulated dead leaf biomass transferred into soil carbon pools. Inventory data from the California Energy Commission also was used to model the carbon dioxide emissions from fossil fuel combustion and greenhouse gas emissions from agricultural lands throughout the state.

This project was funded by NASA as part of a long-term research program dedicated to understanding how human-induced and natural changes affect our global environment.

Ruth Dasso Marlaire
Ames Research Center, Moffett Field, Calif.
650.604.4709
ruth.marlaire@nasa.gov

For more information visit http://www.nasa.gov/centers/ames/news/features/2009/carbon_budget.html

NASA Gets Up-Close Look at Far Corner of the Globe

The Arctic remains in the mind a pristine wonderland. The landmasses that jut into the Arctic Circle are covered by tundra and primeval forest; the pole is covered in ice. The whole environment seems detached from human influence entirely. But the scientific record tells a different story.

A months-long airborne campaign in 2008 gave scientists a new look at how everyday human behaviors in Europe, North America and Asia are affecting the Arctic, the most rapidly changing region on Earth and a major regulator of the planet's climate. The data show human fingerprints all over the Arctic in the form of polluted exhaust from factories and smoke from fires often set by human hands. Observations from the ground have long recorded some of this impact, and satellites in low-earth orbit provide a different view, but scientists had not undertaken a detailed, airborne study of this magnitude in years.

The mission provided a new view of how pollution from industrializing Asian countries influences the Arctic. Ground sensors have long detected the regular, low-altitude movement of polluted air masses from Europe to the Arctic. Because of the colder temperatures in the countries of the pollution's origin, the plumes of carbon dioxide, carbon monoxide and other warming-related gases do not rise high in the atmosphere. On the contrary, pollution from warmer regions in Asia has apparently been moving to altitudes too high for ground instruments to observe well. The airborne instruments provided invaluable measurements of the extent of this pollution, said Daniel Jacob, a Harvard University atmospheric scientist and both mission scientist and co-principal investigator for NASA’s Arctic Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission.

The DC-8 flies above Summit, Greenland. The ARCTAS flights collected a trove of seldom-made measurements of the Arctic atmosphere that are shedding light on the processes at work in the most rapidly warming region on Earth. Credit: NASA

"With Asian pollution, there's a relatively warm ocean immediately downwind of a fairly cold continent, so you have interesting storm tracks that lift pollution and transport it at higher altitudes," Jacob said. "It's certainly a much larger influence on Arctic haze than what had been traditionally ascribed."

Now that researchers have had some time to sift through the data collected, Jacob said the value of these observations is coming in to focus. Major airborne campaigns like this are rare, so almost any study of the Arctic atmosphere in coming years will draw on ARCTAS.

"We're getting to the point where results from ARCTAS are getting into climate models. We’re able to test different models of snow albedoes, and we've been able to introduce some corrections," Jacob said. "From the standpoint of the Asian pollution influence, if you want to claim Asia has a certain influence, you better check it against the ARCTAS results."

While factories, power plants and cars on the highway provide a 365-day-a-year source of pollution, the Arctic flights revealed insights into a more cyclical source of emissions: fires in boreal forests and from agricultural burning as far away as Kazakhstan. In concert with NASA, NOAA sponsored spring flights as part of a field study called Aerosols, Radiation and Cloud Processes affecting Arctic Climate (ARCPAC). These flights observed an unusually active spring fire season. Even if the data collected was somewhat anomalous, scientists say it has provided great insight into fire and smoke influence on the Arctic. In addition, there is some evidence that as the Arctic warms and dries out, there is more fuel for these fires.

NASA's DC-8 casts a shadow on Arctic ice during a campaign in 2008 to measure the presence of pollution from mid-latitude continents and smoke and soot from wildfires in the Arctic atmosphere. Credit: NASA

"We expected to see pollution. But it turns out there's a seasonal cycle to fires, and there’s a springtime peak and summertime peak," said Chuck Brock, ARCPAC project scientist. "I don't think we appreciated that these fires in Siberia and in southern Russia could be so dominant and important in the Arctic. So, is 2008 representative or is it an unusual year? But every year there is this peak, and every year this smoke gets carried to the Arctic."

Brock said the wealth of data will be important in studying the link between smoke and cloud formation and the repercussions of this link. For instance, could there be an impact on snowmelt -- through aerosol-related warming -- if the spring fire season inches up by even a week or two?

The campaigns also provided the opportunity to create a sharper picture of several specific emission sources of greenhouse gases that find their way to the Arctic. Scientists focused on emissions from the oil and gas industry in Prudhoe Bay, Alaska and the natural methane emissions from the massive wetlands near Hudson Bay in Canada. These are two examples of the many variables that need to be accurately characterized in order for scientists to understand what is driving Arctic warming.

It is the rarity of these measurements that makes them important to future study of the Arctic climate, said Jim Crawford, a research scientist at NASA's Langley Research Center and the ARCTAS program manager during the campaign. The data gathered will allow scientists to better interpret satellite observations and better simulate how industrial pollution and wildfire smoke affect the Arctic.

"For scientists interested in studying the role of changing atmospheric composition on climate, the ARCTAS data will represent the best and often only detailed information available for this poorly characterized region," Crawford said.

Related Links:
› ARCTAS Mission

Patrick Lynch
NASA's Langley Research Center

For more information visit http://www.nasa.gov/topics/earth/features/arctas-findings.html

NASA Outlines Recent Greenhouse Gas Research

PASADENA, Calif. -- Researchers studying carbon dioxide, a leading greenhouse gas and a key driver of global climate change, now have a new tool at their disposal: daily global measurements of carbon dioxide in a key part of our atmosphere. The data are courtesy of the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft.

Moustafa Chahine, the instrument's science team leader at NASA's Jet Propulsion Laboratory, Pasadena, Calif., unveiled the new product at a briefing on recent breakthroughs in greenhouse gas, weather and climate research from AIRS at this week's American Geophysical Union meeting in San Francisco. The new data have been extensively validated against both aircraft and ground-based observations. They give users daily and monthly measurements of the concentration and distribution of carbon dioxide in the mid-troposphere--the region of the atmosphere located between 5 and 12 kilometers, or 3 to 7 miles, above Earth's surface, and track its global transport. Users can also access historical AIRS carbon dioxide data spanning the mission's entire seven-plus years in orbit. The product represents the first-ever release of global daily carbon dioxide data that are based solely on observations.

Animation of the distribution of mid-tropospheric carbon dioxide. The transport of carbon dioxide around the world is carried out in the "free atmosphere" above the surface layer. We can observe the transport of carbon dioxide across the Pacific to North America, then across the Atlantic to Europe and the Mediterranean to Asia and back around the globe. The enhanced belt of carbon dioxide in the southern hemisphere is also clearly visible. Credit: NASA

"AIRS provides the highest accuracy and yield of any global carbon dioxide data set available to the research community, now and for the immediate future," said Chahine. "It will help researchers understand how this elusive, long-lived greenhouse gas is distributed and transported, and can be used to develop better models to identify 'sinks,' regions of the Earth system that store carbon dioxide. It's important to study carbon dioxide in all levels of the troposphere."

Chahine said previous AIRS research data have led to some key findings about mid-tropospheric carbon dioxide. For example, the data have shown that, contrary to prior assumptions, carbon dioxide is not well mixed in the troposphere, but is rather "lumpy." Until now, models of carbon dioxide transport have assumed its distribution was uniform.

Carbon dioxide is transported in the mid-troposphere from its sources to its eventual sinks. More carbon dioxide is emitted in the heavily populated northern hemisphere than in its less populated southern counterpart. As a result, the southern hemisphere is a net recipient, or sink, for carbon dioxide from the north. AIRS data have previously shown the complexity of the southern hemisphere's carbon dioxide cycle, revealing a never-before-seen belt of carbon dioxide that circles the globe and is not reflected in transport models.

In another major finding, scientists using AIRS data have removed most of the uncertainty about the role of water vapor in atmospheric models. The data are the strongest observational evidence to date for how water vapor responds to a warming climate.

"AIRS temperature and water vapor observations have corroborated climate model predictions that the warming of our climate produced as carbon dioxide levels rise will be greatly exacerbated -- in fact, more than doubled -- by water vapor," said Andrew Dessler, a climate scientist at Texas A&M University, College Station, Texas.

Dessler explained that most of the warming caused by carbon dioxide does not come directly from carbon dioxide, but from effects known as feedbacks. Water vapor is a particularly important feedback. As the climate warms, the atmosphere becomes more humid. Since water is a greenhouse gas, it serves as a powerful positive feedback to the climate system, amplifying the initial warming. AIRS measurements of water vapor reveal that water greatly amplifies warming caused by increased levels of carbon dioxide. Comparisons of AIRS data with models and re-analyses are in excellent agreement.

Animation of the 3-D transport and distribution of water vapor as measured by AIRS from June through November 2005. Credit: NASA

"The implication of these studies is that, should greenhouse gas emissions continue on their current course of increase, we are virtually certain to see Earth's climate warm by several degrees Celsius in the next century, unless some strong negative feedback mechanism emerges elsewhere in Earth's climate system," Dessler said.

Originally designed to observe atmospheric temperature and water vapor, AIRS data are already responsible for the greatest improvement to five- to six-day weather forecasts than any other single instrument, said Chahine. JPL scientists have shown a major consequence of global warming will be an increase in the frequency and strength of severe storms. Earlier this year, a team of NASA researchers showed how AIRS can significantly improve tropical cyclone forecasting. The researchers studied deadly Typhoon Nargis in Burma in May 2008. They found the uncertainty in the cyclone's landfall position could have been reduced by a factor of six had more sophisticated AIRS temperature data been used in the forecasts.

AIRS observes and records the global daily distribution of temperature, water vapor, clouds and several atmospheric gases including ozone, methane and carbon monoxide. With the addition of the mid-tropospheric carbon dioxide data set this week, a seven-year digital record is now complete for use by the scientific community and the public.

For more on AIRS, see http://airs.jpl.nasa.gov/ .

JPL is managed for NASA by the California Institute of Technology in Pasadena.
> See all images and animations


Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

For more information visit http://www.nasa.gov/topics/earth/agu/airs20091215.html

Just 5 Questions: Aerosols

While the word "aerosol" may conjure up thoughts of things that come in spray cans, it means something quite different to scientists. And it turns out that aerosols have a far bigger role to play in climate change and global warming than originally thought. JPL's Amber Jenkins spoke to Nadine Unger, a researcher at Columbia University’s Center for Climate Systems Research and NASA's Goddard Institute for Space Studies, to find out more.

Unger studies air pollution, the impact of climate change on air quality, and the effects of ozone and aerosol pollution on Earth's climate. She holds degrees in chemistry and atmospheric chemistry from the University of Leeds in the U.K.

What are aerosols? Aren't they the things that come in spray cans?

Aerosols are tiny particles in the air that can be produced when we burn different types of fossil fuels -- coal, petroleum, wood and biofuels -- in different ways. A significant man-made source of aerosols is pollution from cars and factories. If you live in a big city you're probably pretty familiar with soot, an aerosol that forms black layers on your windowsill. But aerosols can also be produced naturally, for example, through being given off from trees or burning vegetation.

The word "aerosol" is used by scientists to mean "atmospheric particulate". But it was used a lot by the media during the 1980s and 1990s to refer to the spray cans that released chlorofluorocarbons (CFCs) into the air, which damage the ozone layer and created the ozone hole. So it's no surprise that there is some confusion over the word!

Nadine Unger

Is there a link between aerosols and climate change?

Yes. Aerosols have a profound impact on the climate because, just like greenhouse gases, they are able to change the Earth's "radiative", or energy, balance. Aerosols can control how much energy from the sun reaches the planet’s surface by changing the amount that is absorbed in the atmosphere and the amount that is scattered back out to space. It turns out that most aerosols are cooling -- that is to say, they reflect the sun’s energy back out into space. There is only one aerosol -- soot, also known as black carbon -- that actually helps contribute to global warming by boosting the warming effects of greenhouse gases in the atmosphere.

Since the Industrial Revolution, humans have pumped more and more aerosols into the air, and this in turn has actually counteracted global warming to a significant degree. Using climate models, we estimate that aerosols have masked about 50 percent of the warming that would otherwise have been caused by greenhouse gases trapping heat near the surface of the Earth. Without the presence of these aerosols in the air, the planet would be about 1 degree C (1.8 degrees F) hotter.

So aerosols are a good thing then?

No. It's true that aerosols have limited the warming that we've experienced on Earth since the Industrial Revolution. But they also have very big, detrimental impacts on human health, and have been implicated in health problems such as lung damage. Aerosols also affect other parts of the climate system like rainfall -- reducing rain in areas like India and China where it is desperately needed for food production -- and they alter patterns of wind and atmospheric circulation.

How can we reduce aerosol levels?

In the US, diesel vehicles are the major source of soot, and filters on exhaust pipes can help reduce the amount that they pump into the air. In terms of sulfate aerosols, which are created by sulfur dioxide given off by power plants, the US and Europe have very successfully used sulfur dioxide scrubbers in power plants to reduce these emissions over the past 20 years or so. But we can definitely do more.

By reducing aerosol (soot) emissions, we can buy ourselves some climate time -- about 5 to 10 years -- while we work on reducing emissions of greenhouse gases such as carbon dioxide (CO2) in parallel. CO2 you see, hangs around in the atmosphere for an extremely long time, from decades to centuries, so even if we implement cuts today, it will take years for them to take effect. Aerosols, on the other hand, have much shorter lifetimes. If we work to reduce soot emissions now, which can enhance the global warming effect of CO2 by 20-50 percent, the climate impacts will be felt more rapidly.

What are you working on right now?

I have a paper in review at the moment that is quite exciting; we're looking at the future total climate impacts of current emissions from different industries, taking into account the effects of both greenhouse gases such as CO2, ozone and methane, and the impacts of aerosols. What we've found is that for the next 40 years, emissions from road vehicles will have the largest global warming impacts of all human activities -- because of the air pollutant effects that enhance greenhouse gas warming. After 2050, however, power sector emissions are by far the largest global warmer because of the build up of CO2 in the atmosphere from that activity.

There are a few other relevant questions coming out of this. In particular, should we be including the effects of aerosols (also known as "non-CO2 effects") in emissions trading schemes? The aviation industry is starting to consider this, but shouldn't we be doing it for all the other industries and sectors as well?


Interview by Amber Jenkins
Global Climate Change/Jet Propulsion Laboratory

For more information visit http://www.nasa.gov/topics/earth/features/Just_5_Questions_Aerosols_20091208.html

AIRS Image Shows Global Carbon Dioxide Transport

This image was created with data acquired by the Atmospheric Infrared Sounder instrument (AIRS) on NASA's Aqua satellite during July 2009. The image shows large-scale patterns of carbon dioxide concentrations that are transported around Earth by the general circulation of the atmosphere. Dark blue corresponds to a concentration of 382 parts per million and dark red corresponds to a concentration of almost 390 parts per million.

Map of global carbon dioxide transport acquired by the Atmospheric Infrared Sounder instrument (AIRS) on NASA's Aqua satellite during July 2009.

The northern hemisphere mid-latitude jet stream effectively sets the northern limit of enhanced carbon dioxide. A belt of enhanced carbon dioxide girdles the globe in the southern hemisphere, following the zonal flow of the southern hemisphere mid-latitude jet stream. This belt of carbon dioxide is fed by biogenesis activity in South America (carbon dioxide is released into the atmosphere through the respiration and decomposition of vegetation), forest fires in both South America and Central Africa, and clusters of gasification plants in South Africa and power generation plants in south eastern Australia.

The AIRS instrument flies on NASA's Aqua satellite and is managed by the Jet Propulsion Laboratory, Pasadena, California, under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/topics/earth/features/AIRSCO2.html

Frost-Covered Phoenix Lander Seen in Winter Images

PASADENA, Calif. -- Winter images of NASA's Phoenix Lander showing the lander shrouded in dry-ice frost on Mars have been captured with the High Resolution Imaging Science Experiment, or HiRISE camera, aboard NASA's Mars Reconnaissance Orbiter.

The HiRISE camera team at the University of Arizona, Tucson, captured one image of the Phoenix lander on July 30, 2009, and the other on Aug. 22, 2009. That's when the sun began peeking over the horizon of the northern polar plains during winter, the imaging team said. The first day of spring in the northern hemisphere began Oct. 26.

The images are available at http://hirise.lpl.arizona.edu/ESP_014393_2485.

"We decided to try imaging the site despite the low light levels," said HiRISE team member Ingrid Spitale of the University of Arizona Lunar and Planetary Laboratory.

"The power of the HiRISE camera helped us see it even under these poor light conditions," added HiRISE team member Michael Mellon of the University of Colorado in Boulder, who was also on the Phoenix Mars Lander science team.

The HiRISE team targeted their camera at the known location of the lander to get the new images and compared them to a HiRISE image of the frost-free lander taken in June 2008. That enabled them to identify the hardware disguised by frost, despite the fact that their views were hindered by poor lighting and by atmospheric haze, which often obscures the surface at this location and season.

Carbon dioxide frost completely blankets the surface in both images. The amount of carbon dioxide frost builds as late winter transitions to early spring, so the layer of frost is thicker in the Aug. 22 image.

HiRISE scientists noted that brightness doesn't necessarily indicate the amount of frost seen in the images because of the way the images are processed to produce optimal contrast. Even the darker areas in the frost-covered images are still brighter than typical soil that surrounds the lander in frost-free images taken during the lander's prime mission in 2008.

As the sun began to reappear on the horizon following the deepest, darkest days of north polar winter on Mars, the HiRISE camera imaged the Phoenix landing site on July 30, 2009, (left image) and in Aug. 22, 2009 (right). Image credit: NASA/JPL-Caltech/University of Arizona

Other factors that affect the relative brightness include the size of the individual grains of carbon dioxide ice, the amount of dust mixed with the ice, the amount of sunlight hitting the surface and different lighting angles and slopes, Spitale and Mellon said.

Studying these changes will help us understand the nature of the seasonal frost and winter weather patterns in this area of Mars.

Scientists predicted that the ice layer would reach maximum thickness in September 2009, but don't have images to confirm that because HiRISE camera operations were suspended when Mars Reconnaissance Orbiter entered an extended safe mode on Aug. 26.

The Phoenix Mars Lander ceased communications last November, after successfully completing its mission and returning unprecedented primary science phase and returning science data to Earth. During the first quarter of 2010, teams at JPL will listen to see if Phoenix is still able to communicate with Earth. Communication is not expected and is considered highly unlikely following the extended period of frost on the lander.

HiRISE is run from the Lunar and Planetary Laboratory's HiRISE Operations Center, on the University of Arizona campus. Planetary Sciences Professor Alfred McEwen is HiRISE principal investigator. Planetary Sciences Professor Peter Smith is principal investigator for the Phoenix Mars Lander mission. The Mars Reconnaissance Orbiter is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, for NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, based in Denver, is the prime contractor and built the spacecraft. Ball Aerospace Technologies Corp., of Boulder, Colo., built the HiRISE camera.

For more information about the mission, visit: http://www.nasa.gov/mro.

Media contact: Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

For more information visit http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20091104.html

Google Earth Application Maps Carbon's Course

Sometimes a picture really is worth a thousand words, particularly when the picture is used to illustrate science. Technology is giving us better pictures every day, and one of them is helping a NASA-funded scientist and her team to explain the behavior of a greenhouse gas.

Google Earth -- the digital globe on which computer users can fly around the planet and zoom in on key features -- is attracting attention in scientific communities and aiding public communication about carbon dioxide. Recently Google held a contest to present scientific results using KML, a data format used by Google Earth.

A Google Earth application reveals carbon dioxide in the lowest part of the atmosphere close to Earth's surface (green tracks) and carbon dioxide at higher altitudes that are immune from ground influences (red tracks). Credit: Tyler Erickson and Google Earth

"I tried to think of a complex data set that would have public relevance," said Tyler Erickson, a geospatial researcher at the Michigan Tech Research Institute in Ann Arbor.

He chose to work with data from NASA-funded researcher Anna Michalak of the University of Michigan, Ann Arbor, who develops complex computer models to trace carbon dioxide back in time to where it enters and leaves the atmosphere.

"The datasets have three spatial dimensions and a temporal dimension," Erickson said. "Because the data is constantly changing in time makes it particularly difficult to visualize and analyze."

A better understanding of the carbon cycle has implications for energy and environmental policy and carbon management. In June 2009, Michalak described this research at the NASA Earth System Science at 20 symposium in Washington, D.C.

Towers across the United States (top), are equipped with instruments by NOAA to measure the carbon dioxide content of parcels of air at single locations. Credit: B. Stephens, UND Citation Crew

A snapshot from Erickson's Google Earth application shows green tracks representing carbon dioxide in the lowest part of the atmosphere close to Earth's surface where vegetation and land processes can impact the carbon cycle. Red tracks indicate particles at higher altitudes that are immune from ground influences.

The application is designed to educate the public and even scientists about how carbon dioxide emissions can be traced. A network of 1,000-foot towers across the United States is equipped with instruments by NOAA to measure the carbon dioxide content of parcels of air at single locations.

The NOAA-equipped towers as represented in the Google Earth application. Credit: NOAA, 2009 Digital Globe

The application is designed to educate the public and even scientists about how carbon dioxide emissions can be traced. A network of 1,000-foot towers across the United States, like the tower above, are equipped with instruments by NOAA to measure the carbon dioxide content of parcels of air at single locations.

But where did that gas come from and how did it change along its journey? To find out, scientists rely on a sleuthing technique called "inverse modeling" – measuring gas concentrations at a single geographic point and then using clues from weather and atmospheric models to deduce where it came from. The technique is complex and difficult to explain even to fellow scientists.

Michalak related the technique to cream in a cup of coffee. "Say someone gave you a cup of creamy coffee," Michalak said. "How do you know when that cream was added?" Just as cream is not necessarily mixed perfectly, neither is the carbon dioxide in the atmosphere. If you can see the streaks of cream (carbon dioxide) and understand how the coffee (atmosphere) was stirred (weather), then scientists can use those clues to retrace the time and location that the ingredient was added to the mix.

A static two-dimensional map of the location of carbon dioxide, averaged for June 2004, becomes dynamic when that same information is presented in the Google Earth format.Credit: Anna Michalak of the University of Michigan

The visual result typically used by scientists is a static two-dimensional map of the location of the gas, as averaged over the course of a month. Most carbon scientists know how to interpret the 2D map, but visualizing the 3D changes for non-specialists has proved elusive. Erickson spent 70 hours programming the Google Earth application that makes it easy to navigate though time and watch gas particles snake their way toward the NOAA observation towers. For his work, Erickson was declared one of Google's winners in March 2009.

"Having this visual tool allows us to better explain the scientific process," Michalak said. "It's a much more human way of looking at the science."

Tyler Erickson, of Michigan Tech Research Institute in Ann Arbor, designed a Google Earth application to educate the public and scientists about how carbon dioxide emissions can be traced. Credit: Tyler Erickson

The next step, Erickson said, is to adapt the application to fit the needs of the research community. Scientists could use the program to better visualize the output of complex atmospheric models and then improve those models so that they better represent reality.

"Encouraging more people to deliver data in an interactive format is a good trend," Erickson said. "It should help innovation in research by reducing barriers to sharing data."

Related Links:

› New Tools for Carbon Detectives: Tracking Carbon Emissions and Sequestration
› Download the Google Earth file
› YouTube: Research in Atmospheric Carbon for North America – Introduction
› YouTube: Research in Atmospheric Carbon for North America – Instructions

Kathryn Hansen
NASA Earth Science News Team

For more information visit http://www.nasa.gov/topics/earth/features/co2_google.html