Beautiful Radiance

Karen Romano Young (right), a freelance writer and illustrator embedded with NASA’s ICESCAPE field campaign, sent this report from an icebreaker headed to the Arctic. You can follow the expedition on the ICESCAPE blog

Here on the U.S. Coast Guard Cutter Healy, heading north toward sampling stations in the Bering Strait, there’s plenty of light — a beautiful radiance nearly around the clock. Since arriving in Alaska on June 12, I’ve only awakened once in the middle of the night to find it dark. Last night at nearly 11 p.m., I sat drinking tea in front of my porthole, and saw a rainbow descend between strips of clouds into the grey Bering Sea. We’re in the land of the midnight sun, and as we continue north the night light will grow longer. It’s the opposite of the conditions that lead to Seasonal Affective Disorder down south where I come from (Connecticut!) For me, it’s joy.

Up here where there used to be more ice, the radiance is, well, radiating. This is the key: the Arctic ice reflects sunlight back into space. If there’s no ice, the sunlight goes into the water, warming it, and creating an environment in which phytoplankton — tiny plantlike algae at the water’s surface — can thrive. There’s less ice because our atmosphere is trapping greenhouse gases — carbon dioxide and methane — and the result is a warming Arctic.

Many of the 40-plus scientists participating in ICESCAPE, a NASA-led research cruise, are involved in studying the effects of sunlight. ICESCAPE stands for Impacts of Climate Change on the Eco-System of the Arctic Pacific Environment, and its purpose is to bring ice scientists and ocean scientists together to gather a greater understanding of the conditions in the Bering, Chukchi, and Beaufort Seas.

Who better to begin a discussion of the sun’s warming effects than a University of Washington scientist named Bonnie Light? Light has been working in the Arctic Ocean since 1998 when, as a grad student, she boarded the Canadian icebreaker Des Grosseilliers, which had purposely pulled up to the edge of the 1997 autumn ice and got fro-zen in through the 1998 thaw. That was the SHEBA (Surface Heat Budget of the Arctic) project, designed to increase understanding of the Arctic system.

Getting frozen in to the ice was a nod to the so-called “father of Arctic science,” Fridtjof Nansen, who purposely did the same a century earlier to prove his theory that the ice cap drifted. One of the purposes of SHEBA was to provide a baseline for under-standing Arctic conditions that might be affected by global warming. Several other scientists aboard ICESCAPE also participated in SHEBA, including Bonnie’s group leader and co-chief scientist Don Perovich.

The flight to the SHEBA site from Barrow, Alaska — the northernmost city in the United States — was the first time Light saw sea ice. “I’d calculated the total square kilometers that the Arctic ice cap occupies many, many times,” she said, “but to be in a little air-plane and fly over it and just see it…this endless stretch of pack ice was really striking.” During the ICESCAPE cruise she is eager to explore the western coast of Alaska for the first time.

“People have told me that the sea ice in the Chukchi Sea has already begun to open up and is very loose this year,” Light says. She expects to be one of the “ice party,” the group of scientists that descends from the deck of the Healy (shown left), via a basket dangling from a crane, to work on the ice. “I don’t know if we’ll get out on it or not. We’ll have to just wait and see what it looks like when we get there. It’s something I’m not sure a satellite can tell you.”

Light is interested in the physics of solar irradiance – what happens to the sun’s light in ice on a small-scale, but also at the larger scale of the melt ponds that form atop sea ice. One of the experiments she’ll conduct involves a comparison of how sun radiates through bare ice and ice that has a melt pond on top. “We already know that melt ponds make really good skylights,” she says. But could they accelerate melting of already-melting ice, hastening the tipping point between ice cover and open sea? Bonnie Light’s ICESCAPE experience could tell.

Image Information: Courtesy of the U.S. Coast Guard (bottom left) and Karen Romano Young (top right).

What's a Wallops?

What’s a Wallops?

The question, posed by an educated Virginia resident, illustrates a general unawareness that the state is home to one of the world’s oldest launch sites — NASA’s Wallops Flight Facility.

The facility, named after John Wallop who was granted the land in 1692, launched its first rocket on July 4, 1945 and has since launched more than 16,000 vehicles. Beyond launches, however, Wallops is home to other modes of space and Earth science, many of which were on display June 5 at an open house celebrating the center’s 65th anniversary.

Perhaps it’s the center’s location that keeps it hidden from the public eye. Nestled 200 miles away from urban areas, on Virginia’s eastern shore near Chincoteague Island, the coastline provides a prime location for launching suborbital and orbital rockets, targets for the military and testing unpiloted aerial vehicles. Being next to the ocean allows NASA to safely test unproven vehicles and also provides a location for conducting coastal Earth science studies.

Wallops hosts a scientific balloon program, on display at the 65th open house. Adrift at high altitudes in Earth’s atmosphere, balloons carry instruments that measure emissions from space, contributing most to astrophysics research. Credit: NASA



Scientists and engineers at Wallops worked with the laser instrument on NASA’s Ice, Cloud, and land Elevation Sa
ESat)that measured the surface elevation of ice until fall 2009. The publiccould learn more about ICESat and plans for ICESat-2 during the openhouse. Credit: NASA


Perhaps the largest draw was the research airport. U.S. Air Force Thunderbirds lined up on the tarmac before taking off for a demonstration at an air show in Ocean City, Md. Credit: NASA

Wallops’ location also lends itself to Earth science research, described in the center’s roadmap as having “a focus on global climate change and the unique dynamics of the coastal zone environment.”

For example, scientists at Wallops have experimented with autonomous boats to study the ocean and atmosphere, and the interaction between the two environments.

From a distance, visitors saw a more science inclined aircraft, NASA’s very own P-3, just back from a mission in Greenland where it surveyed Arctic ice.

Missed the open house? Learn more about Wallops here.

— Kathryn Hansen, NASA’s Earth Science News Team

4 Views of Eyjafjallajökull’s Plume That You Probably Haven’t Seen Before

When the volcano roared to life and began spewing huge amounts of ash and gas into the atmosphere, Eyjafjallajökull’s giant plume stranded millions of travelers and captivated the rest of us as it wafted away from Iceland.

Most images have shown how the plume might appear to a human from space. But to an aerosol scientist, the real excitement comes from the instruments that produce less recognizable images that nevertheless reveal subtle details about the nature of the plume.

One instrument or one satellite alone is not likely to yield breakthrough insights about volcanic plumes. Rather, constant comparisons between numerous sets of datacollected by a variety of satellite, aircraft, and ground-based platformsare most likely to lead to new discoveries.

With that in mind, aerosol scientists from NASA’s Goddard Space Flight Center and neighboring institutions met last month at a special AEROCENTER seminar to share information about some aspects of Eyjafjallajökull’s plume that they’ve studied so far.

Such cross-satellite and cross-platform efforts make it possible to address some of the thorniest problems in the field. Comparing results from several instruments, for example, makes it easier to understand the dispersion of plumes and—with the help of computer models—predict how plumes might behave, noted Santiago Gassó, the Goddard geophysicist who organized the seminar.

Though the scientists have just started picking their way through Eyjafjallajökull data, there are a number of presentations from the meeting to click through if you’re interested. There’s nothing Earth-shattering to report yet, but we did find some views of the plume that you likely haven’t seen in the newspapers. You can find more imagery of Eyjafjallajökull’s eruptionand plume here,here, here, here, here, here, and here.


MISR – Plume Height


NASA scientists used an instrument called MISR aboard the Terra satellite to view the ash plume from multiple angles, and then applied a stereo-imaging technique to derive the height of the ash cloud at different points during the eruption. The result is the colorful image on the right that distinguishes plume height with bright reds (6 km), oranges (5 km), yellows (4 km), greens (3 km), and blues (2 km). The blue, near-surface part of the plume is resuspended ash.  (Image Credit: NASA/JPL/MISR)


CALIPSO – Vertical Profile

The CALIPSO satellite provides a vertical profile of a whole slice of the atmosphere with a LIDAR instrument that shoots laser pulses at the atmosphere below and measures how it reflects off particles in the atmosphere. In this image, captured on April 17 as the satellite passed over France, the plume appears as a wispy band of yellow and red. The thick yellow layer below is air pollution hovering near the surface of France. (Image Credit: NASA/CALIPSO/Winker)


OMI – Sulfur Dioxide (SO
2)



The Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite had eyes for ash as well as something that’s invisible to the human eye: the transparent (and toxic) gas sulfur dioxide (SO2). OMI observed sulfur dioxide billowing out of the volcano at a clip of as much as 10 thousand tons a day. The OMI instrument produced this image, which shows higher concentrations of sulfur dioxide in red and lower concentrations in blue and purple, on April 30—two weeks after the peak of Eyjafjallajökull’s eruption between April 14 and 17. (Image Credit: NASA/OMI/via Joiner)


DLR Falcon – Aircraft LIDAR


A few days after the eruption began, European scientists scrambled a DLR Falcon jet equipped with a LIDAR and other instruments. The LIDAR, cruising at 8 km altitude, detected volcanic ash in the altitude range of 3.5 km to 5.5 km. The ash plume appears as a yellow and green mass above a layer of clouds (seen as the line of rust-colored spots beneath the ash). When the instrument collected this data, the ash had aged four or five days. The white streaks on the image represent areas where the LIDAR did not detect a significant amount of aerosol. (Image Credit: DLR/via Diehl)

— Adam Voiland, NASA’s Earth Science News Team

Satellites Deliver New Watery Truths with Style and GRACE

High above Earth’s surface – 300 miles to be precise – a special set of twins continually unveils new information about our planet. They’re not human twins, nor are they the constellation we know as Gemini. They’ve arguably, however, attained star status in their eight years in space.

They are the Gravity Recovery and Climate Experiment, or GRACE, a pair of NASA and German satellites that fly about 137 miles apart, changing position relative to one another in response to variations in the pull of Earth’s gravity. A microwave ranging system captures microscopic changes in the distance between the two satellites. GRACE responds to gravity changes that occur when mass – primarily water and ice – on or beneath the surface changes.


GRACE satellites fly in sync with one another 300 miles above Earth’s surface changing position with variations in gravity. Credit: NASA

And like many stars, the harmonious GRACE twins have achieved some very big hits. They’ve racked up unprecedented observations of some of the world’s most famous waterways; shed light on ice loss at the coldest reaches of the globe; and rendered first-time measurements of changes in hidden groundwater reservoirs that sustain millions daily.

Though GRACE has also shaken up old ways of studying changes in solid ground – in the aftermath of earthquakes, for example – today’s nod is to the mission’s contribution to water science.

In celebration of a deal inked earlier this month by NASA and the German Aerospace Center to extend GRACE’s on-orbit life through 2015, here are just a few of the mission’s greatest water- and ice-related accomplishments to date:

  • NASA scientists found that groundwater levels in northwestern India have been declining by an average of one foot per year. More than 26 cubic miles of groundwater disappeared between 2002 and 2008 – double the capacity of India’s largest surface water reservoir and triple that of Lake Mead, the largest man-made reservoir in the United States.


The GRACE mission revealed the most accurate estimates to date of groundwater depletion in northwestern India, a region home to more than 114 million. Credit: NASA/GSFC/Matt Rodell

  • GRACE data confirmed the mass of ice in Antarctica decreased significantly from 2002 to 2005, enough to elevate global sea level by 0.05 inches during that period – about 13 percent of total sea level rise observed over the same four years.


— Gretchen Cook-Anderson, NASA’s Earth Science News Team

Jamboree and Jambalaya

The daily grind of a science and engineering career can leave little time to inquire how colleagues in the very next office have been spending their days and months. Toward remedying that, employees at NASA’s Goddard Space Flight Center emerged from their cubicles and offices on June 2 and mingled outdoors, Cajun style, at the center’s second annual Science Jamboree.

Congregating under tents on the Goddard campus lawn, everyone from scientists to secretaries and engineers to interns browsed the nearly 40 tables displaying the latest projects in earth science, astrophysics, heliophysics, and solar system science at the Mardi-Gras-themed event.

NASA scientists including Tom Neumann (right), described work by Goddard’s Cryosphere branch. Pointing to satellite data, he shows May 30, 2010, as having the lowest Arctic sea ice extent on that date since satellite measurements began in 1979. The data drew in people curious to know the state of Arctic ice. Credit: NASA/Kathryn Hansen

“The record is useful, but is there a benefit to predicting the Arctic sea ice extent just a month or so before it reaches its annual maximum?” said one earth scientist, sparking an in-depth discussion. Another visitor proclaimed, “I didn’t know NASA studies snow and ice.”

Other groups arrived with dramatic displays, from demonstrations of merging black holes — winning the “Most Visually Appealing Display” award — to mock ups of current satellite missions such as the Advanced Composition Explorer (ACE).

“ACE is still at it?” asked one visitor. The satellite is nearing its 13th year in orbit.

After snacking on jambalaya and wrestling crayfish from their shells, the crowd poured inside an auditorium for discussions of extreme space weather and of global climate change.


“Preparing for the panel presentation was certainly worth the effort,” said Goddard scientist Claire Parkinson (lower right), who spoke on the climate change panel with Compton Tucker (middle) and Gavin Schmidt (left). “We had a great turnout and the audience engaged us with thoughtful questions.” Credit: NASA/Debora Mccallum


A steady stream of spectators worked their way around the tables and posters describing current science projects. Credit: NASA/Debora Mccallum


NASA science writer Laura Layton spoke with audiences about projects within the heliophysics branch, including the ongoing Advanced Composition Explorer (ACE) satellite mission, which studies energetic particles from the solar wind. Credit: NASA/Kathryn Hansen

The Cryosphere branch showed off ice sheet and sea ice research, airborne studies and satellite missions. Credit: NASA/Debora Mccallum

— Kathryn Hansen, NASA’s Earth Science News Team

Earth Day Extravaganza on the National Mall

Earth Day is still a day away, but already NASA’s exhibit on the National Mall is brimming with activity. On April 17, NASA’s Earth Science Division deputy director Jack Kaye kicked off the festivities by cutting the ribbon on the NASA Village. Here’s just a sampling (and full schedule of events) of what you might find if you come to Washington, DC:

An igloo-shaped tent with a striking resemblance to the Northern Hemisphere (Credit: NASA/Barker) 

Violinist Kenji Williams accompanied by awe-inspiring satellite imagery(Credit:NASA/Chrissotimos)


Puzzle-mania (for all ages) (Credit: NASA/Barker)

Thought-provoking talks about Earth science from leading scientists (That’s Goddard’s Compton Tucker discussing the ocean.) (Credit:NASA/Chrissotimos)
 

A space suit with your name on it (Credit:NASA/Chrissotimos)
 

Stuck at home? No worries. NASA is all over on the web as well. You can take part in this online chat about climate change on April 22nd. And there’s a number of NASA missions and websites—ranging from the NASA Earth Observatory to Earth Vital Signs to NASA Glory to NASA IceBridge–that are always aTwitter with Earth science.

— Adam Voiland, NASA’s Earth Science News Team

Performance Art, Rock Music Reach Engineering Nirvana in OK Go Video

What do NASA techies do with their spare time? They make rock-n-roll videos. Not the big-hair, booty-shaking, smoke-and-fire kind. They help make rock videos that would make their daytime colleagues proud or jealous, or both.

The rock band OK Go prides itself on creative visual expressions of their music, and they wanted an extra dose of gee-whiz fun for their song “This Too Shall Pass.” In early 2010, the group enlisted the help of Syyn Labs — a self-described “group of creative engineers who twist together art and technology.” The Syyn Labs fraternity included (or ensnared) four staff members from NASA’s Jet Propulsion Laboratory.


[Remember to turn your sound on.]

OK Go requested a Rube Goldberg machine as the centerpiece of a video. To borrow from wikipedia, a “Rube Goldberg machine is a deliberately over-engineered machine that performs a very simple task in a very complex fashion, usually including a chain reaction. The name is drawn from American cartoonist and inventor Rube Goldberg.” Think of the classic board game Mousetrap or your favorite chain reactions from Tom & Jerry cartoons.

More than 40 engineers, techies, artists, and circus types spent several months designing, building, rebuilding, and re-setting a machine that took up two floors of a Los Angeles warehouse. The volunteers went to work after work, giving up many nights, weekends, and even some vacation days to build a machine that has drawn more than 13 million views on YouTube.

The JPL staffers included:

  • Mike Pauken, Ph.D., a senior thermal systems engineer
  • Chris Becker, a graduate student at the Art Center College of Design and a JPL intern
  • Heather Knight, a former JPL engineering associate (instrumentation and robotics) who is now preparing to start work on a doctorate at Carnegie Mellon University
  • Eldar Noe Dobrea, Ph.D., a planetary scientist working to study landing sites for the upcoming Mars Science Laboratory.

What on Earth caught up with these rock-n-roll moonlighters to learn more about the machine and video.

What on Earth: What was your role in the creation of the machine, and what was the inspiration behind your piece?

Eldar: My main role was to help design and construct the descent stage (2:06 to 2:28 in the video). The inspiration for the rover was a small Japanese Rube Goldberg machine that had a tiny mock-up of a mouse rover, about the size of a Hot Wheels car. It struck me that since I am representing JPL, we should have a Mars Rover in our machine.

Chris: I helped finish up the sequence of interactions and the filming. I have a couple things that I was involved with, but cannot take complete ownership of any. But during the filming, I redesigned the beginning dominos (0:06-0:18 sec.) and helped set them up between the numerous takes (60+).

Mike: I worked on the tire ramp, mostly focusing on wiring the relay circuits for the lamps that were triggered by the tire. You’ve got to wonder when a mechanical guy does electrical work. A friend from CalTech told me about a band making a music video featuring a Rube-Goldberg machine. Any time I’ve seen one in a movie, like in Pee Wee Herman’s Big Adventure or Chitty Chitty Bang Bang, I’ve always wanted to make one myself.

Heather: I helped make sure all the modules came together in the first half of the video. I also worked on the intro, the Lego table, and the inflatables. There were a few guiding principles behind the machine. No magic: Mechanisms should be understandable and built from found objects where possible. Small to big: The size of the modules and parts becomes bigger over the course of the video. One take: As in their other videos, the band wanted the entire piece shot in one piece by a single handheld camera.

What on Earth: How many “takes” did it take to get the machine to work?

Mike: Before filming, it took more tries to get things right than anyone could ever have counted. Sometimes I’d spend three or four hours just fiddling with one part to get it right. Even then, it often got changed a couple days later to something else.

Heather: We learned something very important about physics in the process of making this video. It is much harder to make small things reliable. Temperature, friction, even dust all greatly effect the repeatability and timing of the small stuff. The first minute of the video failed at a rate that was tenfold of the rest of the machine. Remembering that rule about getting everything in one shot — if your module is further down the line in the video, you’re in big trouble if it doesn’t work! The machine took half an hour and 20 people to reset.

What on Earth: What’s the funniest or strangest thing that happened on the set?

Chris: Realizing that a number of PhDs built one thing and a clown from a circus built another part. There was no hierarchy. Everyone was there for the same purpose: to build a machine that worked and was fun!

Mike: I helped assemble the sequence between the piano and the shopping cart (1:34 to 1:41). The tetherball pole was supposed to trigger the shopping cart, but when we played the song, the timing was off. The band wanted more delay so that the cart crashed at the end of ‘when the morning comes.’ I added in a sequence using a director’s chair, a piano cover, a waffle iron, and a 10-pound weight to give the necessary delay. Heather’s shoe became part of the sequence, too.

The director’s chair has a rope holding one arm in place. My first thought on holding this rope was to use an umbrella, but Heather told me there were already too many umbrellas in the machine. I rummaged around the warehouse and found a high-heeled shoe sitting around a bunch of junk, and I thought this would make a great holder for the rope. I fastened the shoe to a 2-by-4 with three large wood screws, pried off the rubber tip of the heel, and sanded it a bit to allow the rope to slip off with just the right amount of force.

Then Heather walks up with a friend, who says: ‘Heather, isn’t that your shoe?’ I thought she was kidding, but then Heather said, ‘What are you doing with my shoe?’ I still thought they were making a joke, but then I could tell that Heather was serious and getting mad. Then she started laughing and said: “The machine needs a high-heeled shoe!”

What on Earth: What is your favorite part of the machine?

Eldar: I think the beginning, where the ball bearing jumps out of the speaker when the music begins (0:24) is absolute genius. But the guitar hitting the glasses and taking over the music (1:24) is also quite phenomenal in timing and execution. There were so many things in this machine that blew my mind.

Heather: There are various ‘Easter eggs’ from the band’s other videos that are nestled within the machine. The most obvious is the treadmill video playing on the TV that gets smashed (2:37). But there are also references to the Notre Dame marching band video on the Lego table (1:17) — from the tall Lego drummer to the dancing grass people (I made those!).

Chris: My favorite is the falling piano! That thing took such a beating and was screwed together take after take. It only lasts for a fraction of the video, but it has such comical importance and was triggered after one of the best parts of the video — the clinking glasses.

What on Earth: So if you could quit the day job and get paid for such things, would you?

Mike: I don’t think so because I really like my day job. And even though working on the video was great fun, if it became a full-time job, I don’t think it would seem as fun anymore. The build seemed like a college frat house at times, and that would definitely go away if it became a job.

Eldar: No, I work on missions to other planets! This was fun, but the real deal is at NASA. They say that there is no business like show business. They can keep it.

Postscript: If you want to enter the world of music videos – or of the NASA engineer – you can make your own Rube Goldberg machine for the band’s video contest.

Mike Carlowicz, NASA’s Earth Science News Team

The Glory Initiative


Diehard fans of the hit television show Lost, which will air its final episode Sunday, know that the Swan (station number 3 of the mysterious Dharma Initiative) was designed to study strange electromagnetic fluctuations emanating from a tropical island in the South Pacific.

Likewise, thanks to an old orientation video about the Swan that turned up during the second season, they know that the station houses a computer that requires a code be entered and a button pushed every 108 minutes to avoid unleashing powerful forces capable of destroying the island and perhaps all of Earth.

And, finally, they know that Desmond Hume, a character from the show (named after influential Scottish philosopher David Hume), took the instructions in the video to heart and pushed the button fastidiously for years.

What they surely don’t know, regardless of how many hours they’ve spent scouring Lostpedia or regaling perplexed coworkers with Lost trivia, is that engineers for NASA’s Glory mission have a computer and button of their own at the University of Colorado’s Laboratory for Atmospheric and Space Physics (LASP) that’s keeping them up at night.

LASP’s button is related to a “24-hour test”, which is one of many tests that engineers have performed prior to Glory’s expected November 22 launch to ensure the climate satellite will be capable of handling the harsh environment of space. The test required that engineers at LASP follow a protocol nearly identical to Desmond’s notorious button routine.

The protocol was so similar that LASP engineer Patrick Brown, a hobbyist videographer and the person responsible for designing the pointing system of an instrument aboard Glory that will monitor the sun’s irradiance, was inspired to pull together an orientation video of his own. We checked in with Brown to learn more.


Does the clip show an actual test or is it just a spoof?
It’s actually real. The 24-hour test is a comprehensive simulation where we power the spacecraft and both of Glory’s science instruments on to simulate the orbit motion of the spacecraft; it helps to make sure the electronics are working well together. It’s sort of a “day-in-the life” test. LASP was responsible for continuously monitoring Glory’s TIM instrument during the test.

So why make this test into a Lost spoof?
As we were talking about the test protocol, I came to realize it was quite similar to the Lost button-pushing scenario. I suggested jokingly that we should make a parody, and I just did it one night after work. Everything that’s in the video is correct in terms of how we monitor the TIM during the 24-hour-test. It’s almost a 1-to-1 parallel. During the test, we actually had to call Orbital Sciences in Virginia, where the spacecraft  was, every 100 minutes to tell them to turn on the “stimulus”.

What is the “stimulus”?
As part of the test, we have stimulus lamps that simulate the sun. Every one of Glory’s orbits will take about 100 minutes, but we spend approximately 60 minutes in the sunlight and 40 minutes in the dark. We have to have the stimuli lights powered on when to simulate the time we’re in the sunlight and turned off to simulate the time Glory will be in Earth’s shadow.

Do the people on your team look forward to this particular test?
We divide up the time and have about four hour shifts, but the 2 am to 6 am shift definitely isn’t popular. Most of them time you’re looking at the screen, and there’s nothing happening. Still, you have to keep a close eye on the computer, and you can’t use the computer to do anything other than monitor the TIM instrument.

Who have you showed your video to and how did they react?
My coworkers have all seen it, plus my family and friends. The people who know both Lost and Glory absolutely love it. People who aren’t wrapped up in the whole Lost phenomenon have a harder time understanding the irony.

Who’s your favorite Lost character?
That’s a good question, but it would have to be Desmond.

–Adam Voiland, NASA’s Earth Science News Team

Fun with Aureoles and Aerosols

 
      Credit: Earth Science Picture of the Day/Rob Rathkowski


Earth Science Picture of the Day (EPOD)
recently ran a series of photos that illustrates nicely the impact that small airborne particles called aerosols can have on light.

As EPOD notes, the size of an aureole — the halo-like circle that appears around the sun when viewed through a haze or mist — depends on the amount of aerosol in the air. More aerosols mean more light is scattered, which produces larger aureole). Since most aerosols are concentrated near Earth’s surface, the aureole at sea level appears much larger than it would high on a mountain peak. You can try this experiment yourself to get a sense of the aerosol load in the air you’re breathing.

Aerosols are a major preoccupation for climate scientists as the particles—including dust, ash, sea salt, soot, and industrial pollutants—can scatter light and affect Earth’s energy balance. Infusions of ash and sulfate from volcanic eruptions, for example, are capable of cooling global temperatures by 0.3 degrees Celsius. Likewise, sulfate aerosols from factories and power plants can mask global warming somewhat and are often bandied around as possible components of geoengineering schemes.

Want to learn more about how aerosols scatter light? EPOD has another post on the topic that compares aureoles at sunsets in the Netherlands before (below left) and after (below right) the arrival of a massive volcanic ash cloud from the eruption of Eyjafjallajökull. Also, for optics aficionados, a site called Atmospheric Optics will walk you through a number of interesting examples of aerosols and atmospheric water and ice scattering light.


        Credit: Earth Science Picture of the Day/Kosmas Gazeas
— Adam Voiland, NASA’s Earth Science News Team

Extreme Field Campaign

A team from NASA Langley Research Center needed a high and dry place to run their Far Infrared Spectroscopy of the Troposphere (FIRST) instrument last summer and fall. They found it in Chile’s Atacama Desert. Photo courtesy of Rich Cageao, NASA Langley Research Center.

How does a group of NASA scientists end up on a barren mountaintop, a hemisphere away from home, 17,500 feet above sea level, and in need of supplemental oxygen to stay focused in the thin air? Like most things in science, this trek began with a question or two.

“The first question is: what is the science that’s important to do? The second is: how do you do it?”

Rich Cageao said it was these questions that led a group of scientists and engineers from NASA’s Langley Research Center to embark on a four-month field campaign to the Atacama Desert of Chile in 2009, from late July to early November.

To study how water vapor absorbs infrared radiation in the high atmosphere and influences the climate, the group needed a site well above sea level. Otherwise, the higher levels of water vapor near the surface would block any attempt at detailed infrared measurements, like putting a thick layer of gauze in front of a camera lens.

A modified shipping container – like the ones shipped on rail cars and tractor trailers – became a remote office for the scientists and home for their instrument called FIRST – Far Infrared Spectroscopy of the Troposphere). Trucks took it from Virginia to California; a ship took it from California to Chile; a truck again took it from sea level to an elevation equal to the base camp on Mt. Everest. And the container – outfitted with windows, a door, an opening for measurements, and oxygen – made it to and from the site in pretty good shape, despite a few snowstorms and gale-force winds.



Here the site is seen prior to grading and preparation. Photo courtesy of Rich Cageao, NASA Langley Research Center.

Once the container was in place at a graded site on a Chilean mountain called Cerro Toco, the team set to working out the kinks with the instrument and power supply. They also worked on adapting to the daily climb from base camp at 8,000 feet to the work site at 17,500 feet.

The conditions kept everyone on their toes, and nothing ever seemed routine, Cageao said. “Warm days, out of the wind, were zero degrees Centigrade. Winds were typically 25 mph, and up to 60 mph,” Cageao described the days as extremely taxing. Nothing could be called drudgery. The possibility that something could go wrong required a state of hyper-awareness. “You’re not waiting for something to happen. You never sit around.”



After site work, the instrument, housed in a converted shipping container, was put in place in Chile following a
months-long trek by truck and ship.
Photo courtesy of Rich Cageao, NASA Langley Research Center.

But even with the cold, the wind, and the barren, almost lifeless site, Cageao couldn’t pass on the opportunity.

“We have, by nature, that feeling of, ‘we’ve got to get out there,’” he said of many scientists in the office. “We’re much happier in the field. It’s an adventure. It’s good science and it’s challenging.”

So why go to all this effort?

The Earth’s surface emits infrared radiation it has absorbed from the sun. Greenhouse gases partly trap that energy as heat, keeping the planet habitable. But with humans burning fossil fuels and altering the balance of greenhouse gases – and therefore the amount of heat trapped in the atmosphere – scientists need to understand exactly how this process works in order to improve predictions of climate change.

“The primary greenhouse gas on Earth is not CO2. It’s not methane. It’s water vapor,” Cageao said. “And when you drive up the temperature of the atmosphere, you drive up the water vapor, so you better have this right. Having it pretty close isn’t enough.”

— Patrick Lynch, NASA’s Earth Science News Team