• Puzzler #1 showed undisturbed rainforest canopy in Brazil in part of Pará centered near 0° 58′ 37.1994″ S, 56° 42′ 39.5994″ W.
• Puzzler #2  showed two unnamed glacial lakes in Tibet’s Ngari Prefecture centered near 30° 20′ 31.63″ N, 84° 35′ 26.74″ E.
• Puzzler #3 showed a gorge formed by the Katherine River in Australia’s Northern Territory near the entrance of Nitmiluk National Park; it was centered near 4° 18′ 55.929″ S, 132° 25′ 31.1622″ E.
• Puzzler #4 showed salt pans in the floodplain of the Zambezi River centered near 15° 23′ 28.0638″ S, 23° 21′ 7.5528″ E in Zambia’s Western Province.
• Puzzler #5 showed Thetford Forest in southeastern Britain.

Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. In celebration of Earth Month 2013, we’re upping the ante. We are going to release a new puzzler image every day this week.  The fifth image 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. We’ll post the answer to all five puzzlers at 6 p.m. EST on Friday, April 26. 

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 prizes, but we can promise you credit and glory (well, maybe just credit). Later this week when we post annotated and captioned versions of the puzzler images as our Image of the Day, we will acknowledge the people who were first to correctly ID the images. 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, look at this week as a new challenge — can you get all five image locations?

Good luck!

Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. In celebration of Earth Month 2013, we’re upping the ante. We are going to release a new puzzler image every day this week.  The fourth image 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. We’ll post the answer to all five puzzlers at 6 p.m. EST on Friday, April 26. 

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 prizes, but we can promise you credit and glory (well, maybe just credit). Later this week when we post annotated and captioned versions of the puzzler images as our Image of the Day, we will acknowledge the people who were first to correctly ID the images. 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, look at this week as a new challenge — can you get all five image locations?

Good luck!

Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. In celebration of Earth Month 2013, we’re upping the ante. We are going to release a new puzzler image every day this week.  The third image 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. We’ll post the answer to all five puzzlers at 6 p.m. EST on Friday, April 26. 

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 prizes, but we can promise you credit and glory (well, maybe just credit). Later this week when we post annotated and captioned versions of the puzzler images as our Image of the Day, we will acknowledge the people who were first to correctly ID the images. 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, look at this week as a new challenge — can you get all five image locations?

Good luck!

Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. In celebration of Earth Month 2013, we’re upping the ante. We are going to release a new puzzler image every day this week.  The second image 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. We’ll post the answer to all five puzzlers at 6 p.m. EST on Friday, April 26. 

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 prizes, but we can promise you credit and glory (well, maybe just credit). Later this week when we post annotated and captioned versions of the puzzler images as our Image of the Day, we will acknowledge the people who were first to correctly ID the images. 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, look at this week as a new challenge — can you get all five image locations?

Good luck!

Each month, Earth Observatory offers up a puzzling satellite image here on Earth Matters. In celebration of Earth Month 2013, we’re upping the ante. We are going to release a new puzzler image every day this week.  The first image 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. We’ll post the answer to all five puzzlers at 6 p.m. EST on Friday, April 26. 

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 prizes, but we can promise you credit and glory (well, maybe just credit). Later this week when we post annotated and captioned versions of the puzzler images as our Image of the Day, we will acknowledge the people who were first to correctly ID the images. 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, look at this week as a new challenge — can you get all five image locations?

Good luck!

In a true Cinderella story, the underwater volcano proceeded to knock off four higher seeds before meeting another #7 seed—the crack in the Pine Island Glacier—in the final. The matchup was not even close, as El Hierro romped with 91 percent of the votes.

Perhaps sensing its impending victory, El Hierro began stirring in late March 2013. According to Erik Klemetti’s “Eruptions” volcanology blog, earthquake swarms beneath the island suggested that magma was on the move. Perhaps a volcano will soon be popping some lava champagne to celebrate the win.

Here is a walk through the opponents that El Hierro tossed aside on it’s month-long romp through earthly fame:

ROUND 1: Overnight View of Hurricane Sandy (#2 seed, events bracket)

ROUND 2: GOES View of Hurricane Sandy (#3 seed, events bracket)

ROUND 3: New Volcanic Island in the Red Sea (#5 seed, events bracket)

ROUND 4: Night Lights 2012 – Flat Map (#2 seed, Earth at night bracket)

ROUND 5: Flying Through a Crack in the Ice (#7 seed, data bracket)

Hangout participants included:
Josh Willis, NASA’s Jet Propulsion Laboratory
Sophie Nowicki, NASA’s Goddard Space Flight Center
Mike Watkins, NASA’s Jet Propulsion Laboratory
Virginia Burkett, U.S. Geological Survey
Andrew Revkin, Pace University & New York Times Dot Earth blogger

Plus, here’s some background reading on sea level rise.
+NOAA: Sea Level Trends
+NASA Climate Indicator: Sea Level
+Jet Propulsion Laboratory: Sea Level Viewer
+NASA News: What Goes Down Must Come Up
+Earth Observatory: Regional Patterns of Sea Level Change 1993-2007
+Climate Central: Surging Seas
+National Geographic: Sea Level Rise
+New York Times: Sea Level and the Limits of the Bathtub Analogy
+Los Angeles Times: Most in U.S. Concerned about Sea Level Rise, Poll Finds

The visualization below of satellite measurements of NO₂ in the atmosphere revealed the location of shipping lanes in the Indian Ocean. Ships tend to pass consistently along the same paths — through the Red Sea, across the Arabian Sea, across the southern end of the Bay of Bengal, through the Malacca Straits — to major ports in eastern Asia. On any given day, the exhaust fumes from a few ships do not provide a dramatic signal. But by making a long-term average (2005 through 2012) of data, the small day-to-day fluctuations add up to a discernible signal.

One of the other things we did in building this visualization was to mask the land surfaces with light grey, in order to emphasize the NO₂ over the oceans. But what happens if we take off that gray blanket over the land masses?

Oh my! Pretty much anywhere there are people, there’s a saturated pool of NO₂. All of Europe looks like a putrid mass of polluted air, as does eastern China, the cities of the Middle East, the Himalayan regions of India and Pakistan. In fact, pretty much anywhere there are significant human populations, there is NO₂ running right off the scale! You can still see the ship tracks, but it’s the deep, over-saturated brown-orange that grabs your attention.

If you want to show concentrations over land, you need a breath of fresh air, like this:

This is a better way to show NO₂ emissions over land.  Distinct signals show up around industrialized cities in Europe, the Middle East, and southern Asia, as well as fire emissions in equatorial Africa. Eastern China is still a saturated mess, as are some of the major industrial areas elsewhere in China. Heavy industrialization and an increase in automobiles for transportation has resulted in levels of atmospheric pollution in China not seen since the 1940s to 60s in the U.S. and Europe.

But this third map scarcely shows the NO₂ emissions over the sea, and the ship track signals are hardly discernible, even though we are still using the same exact set of data in all three visualizations. So what is going on?

Look carefully at the color palette, or scale bar, below each map describing how different colors reflect different concentrations of NO₂. The high end of the scale has been changed; in fact, it has been multiplied by a factor of ten in the last version. When compared to land-based sources of pollution, ship tracks are quite faint. As much as ships contribute to NO₂ pollution, they can’t compare to land-based sources.

That makes sense, if you think about it. If a single ship emitted the same amount of NO₂ each day as a small coal-fired power plant, you would expect the signals to match. But the ship is not sitting still; it is moving back and forth across thousands of miles of open ocean and its emissions are thinned out over long distances and time. It is only when there are  hundreds of similar ships traveling along the same route that the signal begins to build; and even then, the emissions are still spread across a vast area in a way that land-based sources are not.

So for our story on ship tracks, we made the visualization with tight limits on the NO₂ concentration in order to bring out the signal from the noise. Had we not masked out the land sources, the ship tracks would have been  lost.

Cinderella Baja was finally taken out by the Black Marble, but two other high seeds remain: “Crack in the Ice” and “El Hierro.” If you want to dissect what went wrong (or right) with your picks last week, look below to see how the voting played out. In the data section, we saw the PIG Ice Crack blow out the North American heat wave image, which garnered just 22 percent of the vote. Voyager’s view of Earth also went down hard, earning just 37 percent of the vote against the solar flare.

Don’t forget to vote in the third round. Some key matchups to watch: #1 ranked City Lights of the United States is squaring off against #2 ranked Night Lights 2012. And in the true color section, the Black Marble faces the toughest competition it has seen yet from the solar flare image. Voting closes at 4pm Eastern Time on March 22.

The Black Marble (57%) vs. Baja California (43%)

Solar Flares (63 %) vs. Voyager Far from Home (37 %)

El Hierro (57%) vs. GOES Hurricane Sandy (43%)

Hurricane Isaac (35%) vs. New Volcanic Island (65%)

City Lights United States (66%) vs. Lights of London (34% )

City Lights Nile (47%) vs. Flat Map Night Lights (53%)

PIG Ice Crack (78%) vs. North American Heat Wave (22%)

Tree Map (48%) vs. Antarctic Sea Ice (52%)