ellesmere_ali_2012171

Congratulations to Dillion and Eric J.F. Kelijssen for solving the January Puzzler the fastest.  The answer is Oobloyah Valley on Canada’s Ellesmere Island. The image features four glaciersNukapingwa, Arklio, Perkeo, and Midgetflowing into the valley from the Krieger mountains to the north. At the end of each glacier, all of which are retreating, there are heaps of rock, gravel, and sand known as terminal moraines. As we explained in our Image of the Day on January 18, 2014, the moraines are of interest to ecologists because they offer an ideal natural laboratory for studying how plant species colonize recently exposed terrain.

One team of researchers led by Yokohama National University’s Akira S. Mori focused their search for Arctic plants on the moraine created by Arklio Glacier, the second to the left in the image above. (The Advanced Land Imager acquired this image of the glacier on June 19, 2012.) The moraine, which formed during the Little Ice Age, appears as a lobe-shaped bulge around the end of glacier. The light brown feature south of the moraine is a stream bed. The scientists found two dominant pioneer species living on the rocky, virtually soil-free moraine. The first is Epilobium latifolium, a flowering plant in the evening primrose family known as Dwarf fireweed. The second is Salix arctic, a type of creeping willow.

See Arklio’s terminal moraine and Epilobium latifolium (right) and Salix arctic (left) in the photographs below.

arkliomoraine

The snout of Arklio Glacier with its terminal moraine visible at the center of the image.  An earlier study of the area’s vegetation occurred at Moraine D. Image courtesy of Akiro Mori, Yokohama National University.

salixarctic-epilibium-latifolium

The dominant vascular pioneer plants that grow on Arklio Glacier’s moraine: Epilobium latifolium (right) and Salix arctica (left). Image courtesy of Akiro Mori, Yokohama National University.

Best of the Archives: Dunes of the Great Bahama Bank

January 16th, 2014 by Adam Voiland

bahamas_etm

Thirteen years ago, a satellite acquired this beautiful image (above) of light and sand playing off a portion of the ocean floor in the Bahamas. The caption that accompanied the image didn’t include many details, only noting that the image was acquired by the Enhanced Thematic Mapper Plus (ETM+) sensor on Landsat 7 and that, “tides and ocean currents in the Bahamas sculpted the sand and seaweed beds into these multicolored, fluted patterns in much the same way that winds sculpted the vast sand dunes in the Sahara Desert.”

An image as beautiful as this seemed like it deserved a bit more explanation, so I  grabbed a recent (January 9, 2014) scene of the same area captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. That image (below) shows a much broader view of the area. You can still see some details of the intricate network of dunes, but the MODIS image offers a much better sense of the regional geology.  For instance, you can easily see that the section of dunes shown in the first image (the white box in the lower image) is part of a much larger limestone platform called the Great Bahama Bank. Limestone is a sedimentary rock formed by the skeletal fragments of sea creatures, including corals and foraminifera, and this particular limestone platform has been accumulating since at least the Cretaceous Period. 

You can also see a sharp division between the shallow (turquoise) waters of the Great Bahama Bank and the much deeper (dark blue) parts of the ocean. The submarine canyon that separates Andros Island from Great Exuma Island is nearly cut off entirely from the ocean by the Grand Bahama Bank, but not quite.  A connection to deep waters to the north gives the trench the shape of a tongue, earning the feature the name “Tongue of the Ocean.” At its lowest point, the floor of the Tongue of the Ocean is about 14,060 feet (4,285 meters) lower than Great Bahama Bank. The shallowest (lightest) parts of the Grand Bahama Bank, in contrast, are just a few feet deep.

Bahamas_amo_2014009

January Puzzler

January 13th, 2014 by Adam Voiland

January_Puzzler_2014
Every month we offer a puzzling satellite image here on Earth Matters. The January 2014 puzzler is above. Your challenge is to use the comments section to tell us what the image shows, what part of the world we are looking at, when the image was acquired, and why the scene is interesting.

How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 200 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.

The prize. We can’t offer prize money, but, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID the image. We’ll also recognize people who offer the most interesting tidbits of information. Please include your preferred name or alias with your comment. If you work for an institution that you want us to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the last few months or work in geospatial imaging, please sit on your hands for at least a few days to give others a chance to play.

Releasing Comments. Savvy readers have solved many of our puzzlers after only a few minutes or hours. To give more people a chance to play, we’re going to wait between 24-48 hours before posting the answers we receive in the comment thread.

December Puzzler Answer: The Gulf Stream

December 23rd, 2013 by Adam Voiland

Every month we offer a puzzling satellite image here on Earth Matters. Every month someone seems to figure it out quickly. So in December 2013, we threw down the gauntlet.

For the first time, we put a false-color imagethis swirl of purple and pinkinto play. A week later, we have received many thoughtful responses but no one came up with the answer. The puzzler this month was a swatch of the Gulf Stream as seen in the infrared by the Thermal Infrared Sensor on Landsat 8.

A number of you came pretty close. Kevin Acosta was one of the first to speculate that we were looking at ocean currents, though he guessed it was the Benguela and Agulhas currents south of South Africa. Eric pointed out it was a false-color image of heat, but he was focused on the Great Lakes as opposed to ocean currents.

I was impressed by the sheer diversity of ideas that flowed in. I’ve included a few of the more creative responses below.

“Looks like part of a red algae bloom or ‘red tide’ on the oceans surface. Can be very beautiful, but can also be deadly when seafood gathered from an algae site is consumed.”  M. Lowe, Earth Matters

“Looking at the gas cloud produced after an eruption using thermal imagery probably underwater hence the blue at top of picture. Recent off Japanese coast.”  Duane Elliott, Facebook.

“Looks similar to nickel tailings in Sudbury, Ontario, much like the images shot by Edward Burtynsky. Improper chemical waste is an on-going environmental issue, which definitely needs more exposure.” Brittney Hopson, Facebook.

“Enhanced satellite imagery of a desert area, showing buried aquifer formations which are potential water supplies, GPR perhaps.”  John Munsey, Facebook.

“To me it looks like it is hot lava with the gases swirling with smoke…Iceland…or Hawaii?  Alison Renee Heller, Facebook.

Thanks to all of you for puzzling away with us in 2013. We had a lot of fun looking at satellite imagery, and we hope you did as well. (Missed one of our 2013 puzzlers? We’ve tagged them here.) Looking forward, the puzzler will be back and even more puzzling in 2014. We’ll see you then.

gulfstream_tir_2013099gulfstream_tir_2013099_palette

chile_tmo_2013267_crop_spanish
Las imágenes de satélite son como los mapas: están llenas de información útil e interesante, siempre y cuando tengas una clave. Éstas nos pueden mostrar cuánto ha cambiado una ciudad, cuán bien están creciendo nuestros cultivos, dónde arde un fuego o cuando se acerca una tormenta. Para revelar la riqueza de información en una imagen de satélite haz lo siguiente:

1. Busca una escala
2. Busca patrones, formas y texturas
3. Define los colores (incluyendo las sombras)
4. Encuentra el norte
5. Considera tu conocimiento previo

Estos consejos provienen de escritores y visualizadores de NASA Earth Observatory que los utilizan diariamente para interpretar imágenes de satélite. Te ayudarán a orientarte lo suficiente para extraer información valiosa de imágenes de satélite.

Leer más en español.

Este artículo originalmente fue publicado en inglés en NASA Earth Observatory. Traducción al español de Laura Delgado López, IGES.

December Puzzler

December 16th, 2013 by Mike Carlowicz

puzzler_december2013

Every month we offer a puzzling satellite image here on Earth Matters. Every month someone seems to figure it out quickly. We are feeling like it is time to throw down some gauntlets.

The December 2013 puzzler is above. Your challenge is to use the comments section to tell us what the image shows, what part of the world we are looking at, when the image was acquired, and why the scene is interesting.

How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 200 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.

The prize. We can’t offer prize money, but, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID the image. We’ll also recognize people who offer the most interesting tidbits of information. Please include your preferred name or alias with your comment. If you work for an institution that you want us to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the last few months or work in geospatial imaging, please sit on your hands for at least a few days to give others a chance to play.

Releasing Comments. Savvy readers have solved many of our puzzlers after only a few minutes or hours. To give more people a chance to play, we’re going to wait between 24-48 hours before posting the answers we receive in the comment thread.

Fall AGU, Tornado Intensity, and More

December 13th, 2013 by Adam Voiland

Monarch-butterflies-pacific-grove

It’s that Time of Year
Monarch butterflies congregate in central Mexico every winter. Sandhill cranes stop  at a small section of the Platte River in Nebraska every spring. And earth and planetary scientists congregate in San Francisco each December.

More than ten thousand people converged on Moscone Center this week for the the fall meeting of the American Geophysical Union, a hectic five-day event full of lectures, poster presentations, networking lunches, press conferences, and plenty of coffee and beer. For updates from the meeting, check out Dave Petley at the Landslide blog, Will Morgan at Polluting the Internet, the Barometer Podcast, Real Climate, and Journeys of Dr. G from Laura Guretin.


Tracking Tornado Intensity
Are tornadoes getting stronger?  It’s a complicated and controversial topic among meteorologists, but Florida State University’s James Elsner thinks the answer is probably yes (with an emphasis on probably). Elsner came to that conclusion after analyzing the damage caused by every tornado to hit between 1994 and 2006. “If I were a betting man, I’d say tornadoes are getting stronger,” he noted  during a talk the American Geophysical Union meeting this week. But when asked directly at a press conference whether they were, he resorted to caveats, according to Scientific American. “I’m not doing this [work] to establish the future intensity of tornadoes,” he explained, but to establish a method that someday could indeed determine if the storms are becoming more powerful. For more on the muddled topic of tornado intensity trends, see this detailed post from DotEarth’s Andrew Revkin.


Arctic Cyclones Galore

Remember that strong Arctic storm that whirled near the north pole back in the summer of 2012? A new analysis shows that there are more of them than we thought—40 percent more. From 2000 to 2010, about 1,900 cyclones churned across the top of the world each year, leaving warm water and air in their wakesand melting sea ice in the Arctic Ocean. “We now know there were more cyclones than previously thought, simply because we’ve gotten better at detecting them,” one of the authors explained. “We can’t yet tell if the number of cyclones is increasing or decreasing, because that would take a multidecade view.” Read the press release.

Data Visualization AMA
If you missed the Reddit Ask Me Anything with Earth Observatory art director Robert Simmon, you can find the transcript here.

From Facebook
We post items every day to facebook (and not everything that goes onto Facebook makes it onto our site).  One of the highlights this week was a spectacular montage of astronaut photography put together by film student David Peterson. Look for Don Pettit’s head peering out from the cupola at the end end of the video. If you’re anything like me, you’ll find yourself watching it again. And again. And again.

What’s Your Favorite Space Station Photograph?

November 20th, 2013 by Adam Voiland

Happy 15th Birthday, International Space Station! The first International Space Station component, the Russian Zarya module, was launched in November 1998. In the years since, NASA and its global partners have built a world-class orbiting laboratory and kept a continuous human presence in space since 2000.

I decided to celebrate the occasion by searching through the astronaut photography collection on Visible Earth to find of my 15 favorites. My goal was to find at least one image for each year dating back to 2000, though I couldn’t resist adding a few extras for some years. I also checked our web traffic statistics to see how well my tastes matched with our readers. In a some cases, my favorites were also popular. In other cases, not so much. (Any other fans of crepuscular rays out there?)

But enough about me. What do you think? In the comments section, please send us the links to your favorite astronaut photographs from the ISS. However, we’d prefer if you send no more than three.  And don’t forget to scroll to the bottom of this post for a list of the 15 most popular astronaut photographs on our site.

Sunrise, 2013
ISS036-E-028913 (sunrise 2013)

Elusive Red Sprite, 2012 (12th most popular)
ISS031-E-10712 (red sprite, 2012)

Midwestern USA at Night with Aurora Borealis, 2011 (6th most popular)
ISS029-E-012564 (Aurora, 2011)

Crepuscular Rays, 2011
ISS029-E-031270 (crepescular rays, 2011)

Nile River at  Night, 2010 (3rd most popular)
ISS025-E-09858 (Nile River, 2010)

Sarychev Peak Eruption, 2009 (9th most popular)
ISS020-E-09048 (Sarychev Peak, 2009)

Tokyo at Night, 2008
ISS016-E-027586_tokyo (2008)

International Space Station from Endeavor, 2007
STS118-E-9469 (ISS, 2007)

Total Solar Eclipse, 2006
ISS012-E-21351 (eclipse, 2006)

St. Petersburg and the Gulf of Finland, 2005
ISS011-E-12401-(St.-Petersburg,-2005)

Greenhouses of the Campo de Dalias, 2004
ISS008-E-14686 (greenhouses 2004)

Hurricane Isabel, 2003
Isabel_Eye_ISS2003247 (Hurricane Isabel, 2003)

Mount Etna Erupting 2002
etna2_ISS2002303 (Etna, 2002)

Dhaulagiri, 2001
ISS01E6765 (Dhaulgiri, 2001)

First Image, 2000
iss_thunderstorm-2000

Earth Observatory’s 15 Most Popular Astronaut Photographs (based on website statistics since 2010)

1. Iberian Peninsula at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=76777

2. Montreal at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=48471

3. Nile River Delta at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=46820

4. India-Pakistan Borderlands at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=52008

5. Fire in the Sky and on the Ground
http://earthobservatory.nasa.gov/IOTD/view.php?id=52287

6. Midwestern USA at Night with Aurora Borealis
http://earthobservatory.nasa.gov/IOTD/view.php?id=76201

7. Las Vegas at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=47687

8. Liège at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=80145

9. Sarychev Peak Eruption, Kuril Islands
http://earthobservatory.nasa.gov/IOTD/view.php?id=38985

10. Northwestern Europe at Night
http://earthobservatory.nasa.gov/IOTD/view.php?id=51892

11. Mount Tambora Volcano, Sumbawa Island, Indonesia
http://earthobservatory.nasa.gov/IOTD/view.php?id=39412

12. Elusive Sprite Captured from the International Space Station
http://earthobservatory.nasa.gov/IOTD/view.php?id=78487

13. Looking Down on a Shooting Star
http://earthobservatory.nasa.gov/IOTD/view.php?id=51754

14. Atafu Atoll, Tokelau, Southern Pacific Ocean
http://earthobservatory.nasa.gov/IOTD/view.php?id=37753

15. Hurricane Earl – The Astronaut View
http://earthobservatory.nasa.gov/IOTD/view.php?id=45583

From the Archives: Making Ice Cubes

November 19th, 2013 by Mike Carlowicz

wilkins_sar_2008331

Last week, a city-state sized chunk of ice broke off of Pine Island Glacier (PIG), sending iceberg B-31 into a bay off West Antarctica. Though the formation of the 700 square-kilometer iceberg could be a purely natural event — the result of a floating ice tongue growing too long and losing its balance on the sea — some scientists suspect that changes in Pine Island Glacier are due to changing conditions below.

Five years ago this week, another block of ice broke off of the Antarctic Peninsula (radar image above from November 26, 2008). The seaward edge of Wilkins Ice Shelf spent much of 2008 breaking loose from the continent. Unlike PIG, Wilkins shattered and splintered into much smaller bits. And in that case, few doubted that global warming — or at least warming of the Antarctic Peninsula — played a major role.

NASA satellites are still tracking the last week’s PIG offspring. Check out these images from:

November Puzzler

November 18th, 2013 by Adam Voiland

puzzler_november2013
Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. The November 2013 puzzler is above. Your challenge is to use the comments section to tell us what part of the world we are looking at, when the image was acquired, and why the scene is interesting.

How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 300 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.

The prize. We can’t offer prize money for being the first to respond or for digging up the most interesting kernels of information. But, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID the image. We’ll also recognize people who offer the most interesting tidbits of information. Please include your preferred name or alias with your comment. If you work for an institution that you want us to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the last few months, please sit on your hands for at least a few days to give others a chance to play.

Releasing Comments. Savvy readers have solved many of our puzzlers after only a few minutes or hours. To give more people a chance to play, we’re going to wait between 24-48 hours before posting the answers we receive in the comment thread this time.