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Earth Matters


This month we posed a special seasonal challenge: We asked you to join us for a remote-sensing-themed egg hunt by identifying colorful, oval-shaped lakes and ponds around the planet. Well, as one reader points out, we “asked for it.” Hueva identified a lake in Canada so egg-like that it actually goes by the name “Egg Lake.” And to top it off, Goose Lake is immediately to its north.

The traditional challenge—identify the feature in this satellite image and its location—sent some on a wild goose chase. That’s due, in part, to the fact that there’s certainly more than one way to form an egg-shaped lake. As Viacheslav Zgonnik noted:

“These places are seepages of natural molecular hydrogen (H2). We tested many of them on different continents. Check our the most recent article about Carolina bays – egg-like structures in North Carolina, USA.”

The March puzzler was also puzzling because this lake shape is not unusual—oval lakes show up all over the planet. Michael G commented on the blog:

“Located in northern Alaska, USA. There are hundreds of such lakes, they are increasing in size and number. They are thought to form as a result of climate change (warming) that is especially noticeable in the arctic. The shape of the lakes appear to all orient themselves in the direction of permafrost thawing but the dynamics of this are unknown. Recent theories includes slumping of the permafrost as is thaws through the entire thickness of the layer, instead of just the upper layer. The lakes are among the fastest growing lakes on record, increasing in a linear (hence egg shape) direction at about 3m a year, towards the northeast.”

Excellent guesses! This particular image, however, shows a series of saline lakes in Western Australia. Congratulations to David E. Ways and Owen Earley, who were the first to post correct guesses to the blog and to Facebook, respectively. Paulie also guessed correctly, adding that “this area is a “biodiversity hotspot, mixed in with established intensive agriculture.”

The false-color puzzler image was acquired on October 21, 2015, with the Operational Land Imager (OLI) on Landsat 8. To see what the scene looks like in natural-color, and to learn more about these lakes and the reason behind their various colors, read our March 26, 2016, Image of the Day.

The identity of our puzzler has been revealed, but there’s still time to hunt eggs. Continue sending us the latitude and longitude of your favorite colorful, egg-shaped lake by submitting it as a comment on this blog post. We will include the most interesting lakes sent in by readers in a special image gallery that we will publish later this spring.


NASA’s Earth Observatory brings you a new view of Earth from above every single day. Many of these images are more than just pretty pictures; scientists use satellite-based information to figure out how the planet works and to better understand how and why it is changing on a global scale. But to get a full picture, the view from space isn’t enough. You also need granular observations that can only be gathered from the ground. And that’s the job of many NASA researchers who embark on expeditions each year, traversing land, air, ice, and sea.

NASA has a long history of field campaigns large and small. But 2016 is a particularly busy year as eight major new campaigns get under way. If you like acronyms, you’ll love this list:

  • Oceans Melting Greenland (OMG)
  • Korea U.S.-Air Quality (KORUS-AQ)
  • North Atlantic Aerosols and Marine Ecosystems Study (NAAMES)
  • Arctic Boreal Vulnerability Experiment (ABoVE)
  • COral Reef Airborne Laboratory (CORAL)
  • Atmospheric Tomography (ATom)
  • Atmospheric Carbon and Transport – America (ACT-America)
  • Observations of Clouds above Aerosols and their Interactions (ORACLES)

Watch the video below for an armchair tour and brief explanation of each campaign.

So what on Earth is OMG? Scientists are now in the field to help get to the bottom of sea level rise. Namely, how much is ocean warming contributing to ice loss from below, where glaciers meet the water? Data collected during flights around the island’s perimeter will help find out. Read more about the OMG campaign here, and follow writers in the field with each campaign here.

Also currently under way is the Arctic Boreal Vulnerability Experiment (ABoVE). This campaign covers 2.5 million square miles of tundra, mountains, permafrost, lakes, and forests in Alaska and Northwestern Canada. Scientists use satellites and aircraft study this formidable terrain as it changes in a warming climate. But remote sensing by itself is not enough to understand the whole picture, so teams of researchers are on location to gather more data. Follow their journey here, as told directly by scientists in the field.

Stay tuned as the rest of the campaigns ramp up. It’s been an icy adventure so far. But later this year, scientists with CORAL will assess the condition of threatened coral-based ecosystems in Hawaii, and scientists with KORUS-AQ will study air quality in South Korea. If you want to learn more about those campaigns now, take a look at the story we published about CORAL  or the story we did about KORUS-AQ in March.


Every month on Earth Matters, we offer a puzzling satellite image and ask you to tell us what part of the world we are looking at, when the image was acquired, what the image shows, and why the scene is interesting.

However, this March we have a special challenge with a seasonal theme (at least in the Northern Hemisphere, where spring has sprung). Join us for a remote-sensing-themed egg hunt. And by “eggs,” we mean colorful, oval-shaped lakes and ponds somewhat like those pictured above.

The first part of the challenge is to guess the location of the lakes in the image above, just like we do with our puzzler images most months. The second part is to find other colorful egg-like lakes that you think we’ll like.

When you find a good candidate, send us a screenshot and the latitude and longitude of the lake by submitting it as a comment on this blog post. We will include the most interesting lakes sent in by readers in a special image gallery that we will publish later this spring.

Some other guidance and suggestions:

+Search tools. You can use any tools you like to search for colorful lakes. Google Maps, Worldview, Visible Earth, the Earth Observatory archives, and the Gateway to Astronaut Photography may be useful.

+Make sure your lakes are reasonably large. We’ll be using Landsat (30 meters per pixel) or MODIS (250 meters per pixel) data to make the final images. If you have to zoom all the way in on Goggle Maps to see your lake, you are viewing commercial satellite imagery that has a resolution of a few meters per pixels or less. Lakes should have diameters of at least a few hundred meters to show up well in Landsat imagery.

+The more unusual the color, the better. Submitting a lake with a “normal” color is fine, but it will have a smaller chance of making the cut for our final gallery.

+Earth, please. Our focus will be on lakes on Earth. You are more than welcome to share egg-like features you spot on other planets with us, but they won’t make our final gallery.

+It’s a #SpaceEggHunt. Tag your social media posts about this with #SpaceEggHunt. In addition to the blog, we’ll monitor that hashtag for submissions.

+Explain the color. Tell us why you think the lake has such an unusual color as part of your comment. While part of the goal here is to have fun and hunt for lake eggs to celebrate spring, the final gallery will delve more deeply into the science behind lake color and how that can be useful for scientists.

+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. If you find makes the final gallery, your name will be mentioned.

 Good luck and happy hunting!

February Puzzler Answer: Deforestation in Argentina

March 20th, 2016 by Adam Voiland


It took Gavin McMorrow a mere 30 minutes to solve our February puzzler. As he pointed out, the rectangular patterns were cleared forest areas in Argentina’s Salta province. (Learn more about the area in our February 27, 2016, Image of the Day). McMorrow even recognized this was an Operational Land Imager (OLI) image from Landsat 8. Nicely done, Gavin.

It turns out he is no newcomer to space geography quizzes. In fact, if you follow him on Twitter or Instagram, you’ll find McMorrow is actually somewhat of a space geography connoisseur. McMorrow participated regularly in the #SpaceGeo and #EarthArt quizzes that astronaut Scott Kelly organized while he was on the International Space Station.

He’s also been helping Center of Geographic Sciences geographer Dave MacLean (@DaveAtCOGS) catalog the locations of the photographs that astronauts on the station tweet out from orbit. In some cases, astronauts aren’t sure of the feature they just photographed, and it takes time for all the images to be archived in the official database.

To see what I mean, check out MacLean’s map of Scott Kelly’s Year in Space. You can even choose to see maps for just the tweets tagged as #SpaceGeo or #EarthArt. Also helpful, MacLean (and helpers like McMorrow) track down high-resolution versions of the photos when they can. In the tweet below, for instance, McMorrow is alerting astronaut Tim Peake that an image of snow-covered mountains that Peake tweeted was a shot of mountains in Glacier National Park.

And, oh yes, in his spare time, McMorrow is solving Planet Labs geo-detective quizzes.

For a guy who enjoys space geography this much, should I mention we have a job opening?

Ground Photos: Sand Mining at Poyang Lake

March 17th, 2016 by Adam Voiland

Our March 17, 2016, Image of the Day offered a satellite perspective on how sand mining has changed the coastline of Poyang Lake, the largest freshwater lake in China.  The photographs below provide a view of sand mining from the ground. James Burnham, an ecologist with the University of Wisconsin and the International Crane Foundation, took the photos while conducting field research on wintering waterbirds at Poyang Lake. “Sand mining has compromised the ecological integrity of the lake by contributing to less predictable seasonal water fluctuations and to a series of recent low water events,” he said. “This is a lake that hosts 98 percent of the endangered Siberian Cranes and Oriental White Storks, as well as a significant number of over a dozen other endangered waterbirds in the winter.”


Barges full of sand. Photo Credit: James Burnham, University of Wisconsin/International Crane Foundation.


Sand dredging boat. Photo Credit: James Burnham, University of Wisconsin/International Crane Foundation.

Siberian Crane unison call at Mei Xi Hu in Poyang Lake Nature Reserve. Photo Credit: James Burnham, University of Wisconsin/International Crane Foundation.

Siberian Crane family group at Mei Xi Hu, PLNR

Siberian Crane family group at Mei Xi Hu in the Poyang Lake Nature Reserve. Photo Credit: James Burnham, University of Wisconsin/International Crane Foundation.

Happy Anniversary, GRACE!

March 17th, 2016 by Adam Voiland and Holli Riebeek

Fourteen years ago, a rocket launched a pair of satellites known as the Gravity Recovery and Climate Experiment (GRACE) from the Plesetsk Cosmodrome in Russia. Though just 487 kilograms (1,074 pounds) each, the satellites have produced out-sized scientific advances. As we noted in 2012, few hydrologists believed the satellites would be able to detect—no less measure—changes in groundwater when they launched. As the map below shows, scientists working with GRACE data have shown otherwise.


This map shows how water supplies have changed between 2003 and 2012. GRACE measures subtle shifts in gravity from month to month. Variations in land topography or ocean tides change the distribution of Earth’s mass; the addition or subtraction of water also changes the gravity field. During that period, groundwater supplies decreased in California’s Central Valley and in the Southern High Plains (Texas and Oklahoma)—places that rely on ground water to irrigate crops. Eastern Texas, Alabama, and the Mid-Atlantic states also saw a decrease in ground water supplies because of long-term drought. The flood-prone Upper Missouri basin, on the other hand, stored more water over the decade.

GRACE has observed a number of significant changes in the water cycle. For instance, the mission revealed losses in ice mass on Greenland (where the loss is dramatic), Alaska, and Antarctica. The gravity measurements revealed how much the melting glaciers are contributing to sea level rise by recording both ice lost from land and the mass gained in the ocean. The image below shows changes in the Antarctic ice sheet between 2003 and 2010 as measured by GRACE.


GRACE measured changes in the Antarctic ice sheet from December 2003 through 2010. Red areas lost mass, while blue regions gained mass. (NASA map adapted from Luthke et al., 2012.)

As seen in the set of maps below, GRACE-based measurements can also be combined with ground-based measurements to map water at the surface, in the root zone, and as groundwater.


These maps compare conditions during the week of August 20, 2012, to the long-term average from 1948 to the present. For example, dark red regions represent dry conditions that should occur only 2 percent of the time (once every 50 years).

Thank you, GRACE! Here’s to many more years of observations. You can learn more about the mission here. Launch and clean room photos available here.

Remembering Tohoku Earthquake

March 11th, 2016 by Adam Voiland


On this day five years ago, the largest earthquake in modern Japanese history shook the mainland region of Tohoku. The tsunami that followed was devastating. Nearly 16,000 people were killed, and more than 127,000 buildings completely collapsed. The wave triggered power outages, explosions, and reactor meltdowns at a nuclear plant in Fukushima.

What is perhaps most tragic about the quake is that early-warning systems initially underestimated the magnitude of the event. If these systems had gotten it right, word may have spread more rapidly along Japan’s coast that a massive wave was fast approaching.

Five years later, seismology remains as one of the most unsettling fields of Earth science. As the New Yorker put it: “For seismologists, the Tohoku earthquake was a humbling reminder that our geophysical records offer only a peephole view of Earth’s behavior over time, and that our most advanced models for geological phenomena are cartoonish oversimplifications of nature.”

To learn more about the earthquake, see this gallery of NASA Earth Observatory images. Among the images included is the wave height map at the top of the page, and the closeup view of damage in the town of Rikuzentakata seen below.

Tournament Earth: Round 2 Open for Voting

March 8th, 2016 by Kevin Ward

Tournament Earth 2016 Round 2

How did you fare in the opening round of Tournament Earth 2016? One of my favorite photos, showing Mauna Kea volcano has already gone down in defeat. The top seeds moved on to the next round with the exception of Laguna Colorado that fell to an upstart view of New Zealand in sunglint. What will happen in Round 2? Anything is possible. Polls are open for you to vote for the sixteen images that remain through Friday at 4:00 p.m. EDT / 8:00 p.m. UTC. Vote at

Himalayan Heights

March 4th, 2016 by Adam Voiland

On March 1, 2016, NASA astronaut Scott Kelly returned to Earth after spending 340 days living continuously in space. That’s a record. No other American astronaut has completed a longer mission or spent more cumulative days in space.

A prolific and talented photographer, Kelly posted hundreds and hundreds of photographs of the Earth below to social media during his flight. In a fitting finale for the record-breaking explorer, one of the last photos he posted from orbit was this hazy blue scene of the Himalayas.

“The Himalayas remind me of the bigger view we see when we conquer the mountains we climb,” he said on Twitter. The tip of mountain Mount Everest is about 8.8 kilometers (5.5 miles) above sea level; Kelly was in orbit about 250 kilometers above sea level. Over the course of the mission, he traveled some 231,498,541 kilometers.

Congratulations, Scott, on your safe return. Thank you for the beautiful photos. And keep climbing.  (The image below, an astronaut photograph taken in 2013, shows K2, one the most treacherous mountains in the world for climbers. Read more about the 8K peaks here.)



Remember to Vote

March 1st, 2016 by Mike Carlowicz

Here in the U.S., it’s election season. Don’t forget to vote.

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