Month: September 2010

Earth Buzz: Summer Temps, Icy Interactive, and More

How Warm Was This Summer?
…The 4th warmest on record. The Goddard Institute for Space Studies has all the details.  (NASA, Earth Observatory, GISTEMP)

Interactive Ice
The world’s ice–on both sea and land–is changing.  See it with your own eyes. (Eyes on the Earth)

December 2012
You’re not going to die.  The world’s not going to end.  Can we talk about something else now, please? (JPL Video)

G. Projector, What?
You’ve never heard of it, but it’s the best map processing software on the internet.  (Elegant Figures)

 
Inside AERONET
Goddard’s Brent Holben offers a tour of the robots on his roof (NASA Explorer)
 
Venus + Moon + Lake
…Equals a breathtaking photo. (Earth Science Picture of the Day)
Tweet of the Week
Look mom, no Photoshop! Check out this awesome image from our friends @APOD An Airplane in front of the Moon bit.ly/ckMCri  (NASA_GoddardPix)
 
 
–Adam Voiland, NASA’s Earth Science News Team
 
Summer 2010 temperature image courtesy of the NASA Earth Observatory

What On Earth (Sound) Was That #4? Seismic Music From Earth, Of Course…

Last week, we posted our first mystery sound in our latest installment of “What on Earth is That?”> We had some interesting guesses; one reader guessed the noisemaker was an earthquake and another guessed it was a calving ice. The answer is somewhere in the middle.

Giant icebergs may sink ships, but they also have their weaknesses. The sound you heard is the seismic signal recorded in October 2005 when a monstrous iceberg drifting off the coast of Antarctica’s Cape Adare crashed into the previously unknown Davey Shoal and broke apart. (Science News covered the collision in this July article.)  The full length of the audio file, sped up by a factor of 100, can be heard below. Within just 90 seconds, you can experience the full 2.5-hour event.

The “tap, tap, tap” is from cracks propagating through the massive chunk of ice. The effect is similar to what you hear if you drop ice cubes into a glass of water. The cracking noise crescendos until about 1:15, followed by a subtle hum resembling a muffled chain saw. That noise, from the phenomenon of ice pieces rubbing against each other, becomes most noticeable after the breakup. The same saw-like noise heard prior to 1:15 is thought to be the bottom of the berg rubbing on the shoal.

The audio comes from a study published June 18 in Journal of Geophysical Research. Looking at images from the Moderate Resolution Imaging Spectroradiometer on NASA’s Terra and Aqua satellites, the team noticed that between 1989 and 2005, at least three large bergs drifting off Cape Adare had suddenly stopped and broke apart. To discover the cause behind the bergs’ unusual behavior, the team turned to an iceberg called B15A.

Fortunately, plenty of information about the behemoth berg, which measured about 820 feet vertically and spanned some 75 miles by 19 miles, was available. Before the breakup, scientists had deployed an instrument package on B15A that included GPS and a seismometer. Later, a separate research group mapped the seafloor topography within the same area. “We knew from breakup that there ought to be something there,” said Seelye Martin, of University of Washington in Seattle, who led the study.

Overlaying the satellite images on the seafloor map, researchers recreated the series of events. On October 28, the berg hit the top of an underwater shoal 5.6 miles long and 705 feet below the surface at its highest point. The seismic information, heard in this post, matched the collision observed in the satellite imagery. Listening to the seismic music of the Earth is not new; geologists have long listened to the “rock music” of seismic waves from earthquakes. “But the iceberg has a very different signature,” Martin said. “Earthquakes sound like a big boom or slip, while in this case you can actually hear something breaking up.”

So what does it all mean? “It’s an interesting result, but it’s not a world changer,” Martin said. “We now know a little more about the obstacles — and sound — of some ill-fated icebergs leaving the Ross Sea.”

— Kathryn Hansen, NASA’s Earth Science News Team

Images and sound are courtesy of Seelye Martin, University of Washington

Behind the Scenes With Scientists Who Created A Global Air Pollution Map

Yesterday, NASA posted an article about a new global map of health-sapping PM2.5 air pollution. The Dalhousie University researchers who made the map used data from NASA’s MISR and MODIS satellite instruments, as well as information from a computer model called GEOS-Chem. You can read the news story here (or the accounts from Wired, Public Radio, and UPI), but we also wanted to share some of the audio from our interview with the scientists for those who want more details. The scientists being interviewed are Aaron van Donkelaar and Randall Martin; the person asking the question is Goddard-based science writer Adam Voiland.

What was the most interesting thing you found from this analysis?  

Why go to the trouble of making this map?

What’s the heavy band of particulate matter in Africa? Is dust bad for our health?

Martin: There’s no lower bound on health effects

Have other researchers done this kind of analysis?

Are these data ready for prime time?

How did you combine data from both satellite instruments?



–Adam Voiland, NASA’s Earth Science News Team

Lightning Never Strikes Twice, But…



Though the old adage that lightning never strikes twice generally rings true,apparently lightning can strike in very short order in more than a dozenpoints alongside one another as it did near Keota, Colorado on August6. Photographer Robert Arn captured this bedazzling time-lapsed display of lightning over less than 30 seconds across Pawnee National Grasslands while awaiting darkness to fall at a stargazing party.

Speaking of flashes of brilliance, far from the prairies and big skies of the Plains, NASA’s Lightning Instrument Package, or LIP, flew aboard an unmanned, storm-chasing Global Hawk aircraft earlier this month over the Gulf of Mexico and the Atlantic Ocean detecting and documenting lightning during intensifying hurricanes. LIP and 14 other instruments were part of the Genesis and Rapid Intensification Process mission, commonly called GRIP, which drew to a close this week. Scientists expect the GRIP field experiments will eventually yield the most comprehensive data about hurricanes to date once scientists analyze 40 flight days’ worth of new information.

NASA’s Earth Science Picture of the Day Web site featured the white lightning strikes above on September 7, 2010. To see more images recorded by amateur and professional photographers and to learn more about Earth Science Picture of the Day, click here.


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

Image Courtesy of Earth Science Picture of the Day; Photo by Robert Arn  

What on Earth is That? #2


(Please post your guesses and your name in the comments, and we’ll give the answer next week…)

Here at What on Earth, we’re constantly stumbling across interesting photos, videos, and audio clips from NASA’s exploration of our planet (be it from space, the field, or the lab.) Whether it’s a satellite montage captured from thousands of miles up, the roar of our B-200 research aircraft, or a microscopic view of a cloud droplet, there’s literally always something strange and wonderful passing across our desks.

To have a little fun (and spare all that fascinating stuff from the circular file), we’re going to post snippets of it every now and then, usually on Fridays. What we post will change, but the question to you all will always be the same: “What on Earth is that?”

Our only hints:

1) Our picks will always be related to Earth science in one way or another

2) It will have some relation to what we do at NASA.

We’ll give you a week to post your guesses, and we’ll post the answer the following Friday. In the meantime, check out the answer to What On Earth is That #1 here.  

What on Earth was That #2

Last week, we asked you to identify the flecks in a video posted to What on Earth is That #2, and we received all sorts of replies. The correct answer?

They may look like twinkling stars, but the shimmering flecks in this video are actually some of the tiniest particles in the ocean. This clip shows a complex mixture of the miniscule particles, both organic (living) and inorganic (nonliving) types. The large, fern-shaped specimen on the lower right is a type of phytoplankton. Some of the other flecks are likely bacteria and viruses.

Did you notice the slight vibrating motion that makes all the specks look like they’re flickering? That’s caused by random collisions with atoms, a phenomenon called “Brownian motion.” By measuring the distance each particle is pushed around, it’s even possible to infer particle size, which is important for understanding how the particles scatter sunlight in the ocean and for interpreting what ocean-observing satellites “see.”

Image and video Information: This sample was pulled from the Arctic’s Chukchi Sea on June 29, 2010, as part of NASA’s ICESCAPE mission. Kuba Tatarkiewicz, of the Scripps Institution of Oceanography, captured the action with a NanoSight instrument — a camera, microscope and viewing unit that the team adapted for use during the ICESCAPE oceanographic voyage.

-Kathryn Hansen, NASA’s Earth Science News Team

What On Earth Was That #3 ?

Last week, we showed you this mystery image. What was it? As a number of readers—including Brad Halderman (comment #3), Budi Prasteya (comment #7), and others—correctly guessed, you’re looking at a cropped version of one of the famous “sailing stone” tracks located on the Racetrack Playa in Death Valley National Park.

Since the 1940s, researchers have documented the distinctive furrows behind rocks at a number of dried out lake beds in Death Valley. Yet, nobody has actually seen the rocks move or proven definitively how the tracks form. Animals, earthquakes, and gravity have all been ruled out. Some researchers have suggested that the composition of the rock might be a factor, but tests have shown most of the boulders are run-of-the mill dolomites, basalts, limestones, gneisses, and schists that aren’t unusually slippery.

One of the best theories left standing: a combination of wind, mud, and ice. The area receives strong gusts of wind, and episodic bursts of rain that can create slicks of mud for brief periods. During cold weather, thin layers of ice can carpet the playa, and many scientists believe that wind, with the help of ice and mud underneath—has enough force to slide the boulders.

Though science journalist Brian Dunning has an interesting video that shows the movement of ice on the playa, no one has filmed wind actually moving the rocks. In the meantime, researchers (including a recent group sponsored by NASA) continue to investigate the phenomenon, as a NASA news story reported earlier this summer. 

–Adam Voiland, NASA’s Earth Science News Team

The image above is available through  NASA Goddard’s photo and video flickr feed

Earth Buzz: Beautiful Igor, Smoke, and More



Beautiful Igor
Astronauts have called the massive storm in the Caribbean “Igor the Horrible”, but from above the monster of a storm sure looks stunning. (Earth Observatory)

Up in Smoke
Fascinated by fire? It’s not just firefighters and arsonists. NASA researchers, such as Langley’s Elena Kukavskaya, make careers of tracking smoke. (Langley)

Beetle-Mania
Mountain Pine beetles could be priming the pump for huge wildfires in the Rocky Mountains. (NASA Explorer)

GogBlog Video Rewind
Hurricane Alley sends storms barreling up the Atlantic coast every year in late summer and early fall, but how do the giant storms actually form and why? (Geeked on Goddard)

Evolution from Afar
NASA’s ASTER instrument offers a satellite view of the world-famous Australopithecus Afarensis Lucy. (My Big Fat Planet)

Icy Adventures
Learn how just one satellite–the recently departed IceSat–measured the thickness of ice sheets, the health of sea ice, and even the height of the world’s forests. (Goddard Cryospheric Sciences Branch)

Satellites, Ice Sheets, and Earth’s Shifting Surface(Oh My)
New calculations suggest the melting of the Laurentide ice sheet has shifted Earth’s surface and center of mass. (JPL)

Stayed Tuned
The annual Arctic Ocean sea ice minimum is coming in the next few weeks (as is the annual maximum of the ozone hole over Antarctica). In the meantime, check out this snapshot of the polar region captured by Aqua in early September. (NASA.gov)

Image courtesy of the NASA Earth Observatory

What On Earth (Sound) Is That? #4

Regular readers know the drill by now: Every other Friday we post a snippet of one of the many strange and fascinating bits of earth science that pass through our inboxes here at What On Earth, and then you all have a week to show off your science savvy by hazarding a guess (or two or three, if you’d like) in the comments. The last clue was an easy one, but we’re predicting this one–our first sound–will stump most of you.  Listen up, and prove us wrong…


Remember, the answer usually has something to do with….
a) Earth Science
b) NASA


Something on your mind? Email us suggestions and feedback at nasawhatonearth@gmail.com  

Piloting Through Hurricane Earl

NASA scientists are deep into a two-month airborne hurricane research campaign known as GRIP (Genesis and Rapid Intensification Processes). GRIP is designed to put multiple aircraft, outfitted with scientific instruments, above a hurricane at the same time, allowing scientists to observe these destructive storms for longer periods than ever before. GRIP is breaking new ground by flying the unmanned Global Hawk at 60,000 feet above the surface, the first time NASA has used this drone in a hurricane field campaign.

But the NASA’s DC-8 and WB-57 planes get to a hurricane the old-fashioned way — with pilots in the cockpit. Dryden Flight Research Center DC-8 pilot Dick Ewers spoke to the media in Ft. Lauderdale, Fla., last week about what it takes and what it’s like to fly into the heart of a storm that your average pilot would try to avoid entirely. What On Earth was on hand to get some of his thoughts.

What should a first-time rider expect on a DC-8 flight through a hurricane?

It’s pretty bumpy at times, but most of the time it’s a lot of clouds. Then, as we get closer, we’ll go into some bumps and turbulence. As we break out into the eye, hopefully we’ll be able to see the sky above and all the way down to the water below. That’s very nice. All the sudden you’re out of the car wash and you’re looking down and can see what’s happening below. Normally it’s about 10 to 15 minutes of excitement per hour.

What’s the strongest Earl was when you flew through it?

At our level it was about 100 mph, but the worst part is down below. We’re above where it’s very intense. And when you’re flying in an airplane and through an airmass, and the airmass is moving at 100 mph, you don’t really notice that. But what you do notice is when you come out, the winds drops off and the airplane rises and falls based on what’s happening around it. So the plane isn’t able to be very level at times.

What’s your strategy to make sure the plane rides smoothly?

Most of the time it’s very solid. It’s bumpy but it isn’t weaving back and forth.

Even in 100 mph winds?

Oh, yeah. It goes right through it.

Is there a level of risk involved?

My job is to take the risk out of it. My job is to make sure what I do is safe and doesn’t put the scientists or the instruments at risk. My whole mission is to make sure that plane is back here tonight. Where the risk and danger is, I will take precautions and go around it and do something to avoid something where danger is involved.

How many flights did you make through Earl?

This will be the fourth and final flight. We thought it was declining yesterday, but it’s stronger this morning, so we’re going back out.

How was the view of the eye?

There are rare storms that are very crystal clear. This one had a lot of strataform in there, so there were clouds around and some clouds above us, so it wasn’t a pristine, clear blue eye. But you were able to see daylight above us and the water below us. I want to say it was 20 to 25 miles wide inside. You wouldn’t want to be in a boat down there.

— Patrick Lynch, NASA’s Earth Science News Team

Images taken by Patrick Lynch during the Sept. 2 GRIP media day in Ft. Lauderdale, Fla.