Earth Matters

Through May 15, 2021, the GLOBE Program is hosting the 2021 Trees Community Challenge, a project aimed at making science better together by encouraging participants to collect data and learn about trees.

Using the Trees Challenge Activity Tracker, participants can pick and choose activities – or complete all of them – to become members of the NASA citizen science community. Activities include taking a tree height observation, writing a tree poem, and sharing stories about trees that are special to you on social media

Trees are diverse and tree height can tell us a lot about Earth’s ecosystems. Satellites and ground-based measurements are used to track tree growth, monitor how well an ecosystem supports trees, and estimate how much carbon is stored by trees. The GLOBE community encourages #CitizenScientists to use the GLOBE Observer app to take tree height measurements with their smartphones.

Read more about the challenge and how to participate.

The Marvels of Banks Island

January 27th, 2021 by Kathryn Hansen/NASA Earth Observatory, and Robie Macdonald/University of Manitoba/Dept. of Fisheries and Oceans

On July 18, 2015, the Operational Land Imager (OLI) on Landsat 8 acquired this natural-color image of Banks Island. 

In a typical year, perhaps a dozen people visit Auluvik National Park in Canada’s Northwest Territories. Luckily, one of those visitors brought back some outstanding photos.  

In November 2020, we highlighted a few compelling features around the Thomsen River estuary on Banks Island, including lines of sea ice tracing the shoreline and the braided pattern of the river. But there’s so much more to explore across this remote lowland tundra and river valley. 

Robie Macdonald, a scientist at the University of Manitoba, shared some photos that he shot while doing fieldwork in the region between 2014 and 2016. The purpose of that project, led by Matt Alkire of the University of Washington, was to collect geochemical measurements from small rivers across the Canadian Arctic Archipelago. 

“I really do love working in these places,” Macdonald said. “Once the aircraft has landed, one is bathed in a tremendous silence broken only by waves breaking on shingle. Then you have this incredible tundra spreading out toward the hills that define the river floodplain.” 

Here are ten of Macdonald’s favorite photographs.  

1. Ponds and Oxbows

“Numerous ponds of all sizes populate the drainage basins of Banks Island, and you can see several clusters of them in the satellite image (top), especially along the small river to the west of the Thomsen. This photograph provides a closer look at one such pond cluster. In the image, you can also see textbook oxbows, which have become the setting for more ponds.”

2. Permafrost Polygons

“During breeding season, it seems like almost every pond on Banks Island has its own population of snow geese (visible in this photo). You can also see old permafrost polygons that are now submerged within the pond. Polygons are widespread features of the permafrost in soil-rich locations and are produced over time by freeze-thaw cycles of the surface active layer. Permafrost thaw is widely impacting these regions, leading to feedbacks in the carbon system (CO2, CH4).”

3. Vibrant Vegetation

Photo by Robie Macdonald/University of Manitoba

“Perhaps the most surprising characteristic of the valley bottoms in this ‘Arctic desert’ is the vibrant color of the vegetation: yellows, greens, and reds mark a dense ground cover that can be seen on the satellite image as areas with a yellowish-brownish cast.”

4. Sediment Ripples

“As a result of the strong sediment supply, the large embayment at the Thomsen River mouth has been practically filled with sediment. The shallow water reveals itself in the satellite image by the lighter-greenish tone compared to water out in the channel north of Banks Island.  More evidence of the ample sediment supply can be seen in beautiful displays of sand/silt ripples in the lower river between the islands. In the satellite image (top), the ripples are almost visible as grey zones between the islands before the river enters the open bay.”

5. Ice Shoves

“When walking on these islands near the river mouth, you can see evidence of bank erosion and ‘ice shoves.’ These are produced when wind forces newly formed ice to ride up over the river bank and gouge out the top layer of the silty material that makes up these islands.  Unfortunately, ice shoves are too small to show on the satellite image.” 

6. Vulnerable Permafrost

“Global warming and the extensive loss of sea-ice cover in late summer have helped accelerate coastal erosion and permafrost slumping. This image shows a section of coastline just to the east of the Thomsen River mouth that consists of a lot of frozen ice. This sort of permafrost is especially vulnerable to the changing temperature regime.” 

7. Erosion and Slumping

Photo by Robie Macdonald/University of Manitoba.

“Thaw slumps are also a sign of the permafrost warming. These can be seen just barely in the satellite image as small dark regions along cliff faces–both facing the ocean and within the river drainage basins. Erosion and slumping expose ancient organic carbon to the air and the hydrosphere, thus providing an extensive positive feedback to climate warming.” 

8. Bergy Bits

“Lines of bergy bits has collected along a thin shore margin at the point where the sea bottom rapidly deepens below ice keel depths, likely at approximately 2-4 meters. Although the grounded ice bits are continually melting, they are resupplied by more ice chunks shed from the permanent pack out in the channel. Two turbid plumes supplied by a river to the west of the Thomsen easily pass through the necklace of ice.”

9. Sampling Amid an Icy Barrier

“When we were sampling the water in this region, we found this ice barrier to be a bit more of a problem to navigate in our small inflatable boats, but ice along the shore did make it simple to sample sea ice. This image shows Greg Lehn preparing to launch our boat.”

10. A Suitable Landing Spot

Sampling in the Thomson River itself was somewhat simpler, once we had found a suitable place to land the plane. This image shows Greg Lehn scoping out the shore of the Thomsen River near its mouth.” 

EO November 2020 Puzzler

November 3rd, 2020 by Mike Carlowicz
EO’s November 2020 puzzler

Every month on Earth Matters, we offer a puzzling satellite image. The November 2020 puzzler is above. Your challenge is to use the comments section to tell us what we are looking at, where it is, and why it is interesting.

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, 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 feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip to Mars, but we can promise you credit and glory. Well, maybe just credit. A few days after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have shaped the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

UPDATE on November 9 — The answer is a phytoplankton bloom near the Jason Islands, an archipelago off of the Falkland (Malvinas) Islands. Read more about it here. Evzen Schulc quickly identified that it was an ocean bloom, though no one managed to identify the location.

A Closer Look at Fire Types in Bolivia

October 30th, 2020 by Adam Voiland

For the second year in a row, fierce fires have burned throughout Bolivia. They are the product of a prolonged drought, which has supercharged the fires that are lit seasonally by farmers and ranchers to maintain grazing land and to clear forest and woodlands for agricultural production.

This map shows the locations and sizes of fires detected along the northern border of Santa Cruz (Bolivia) and Mato Grosso (Brazil) through mid-October 2020. Yellow represents understory fires; red are deforestation fires; blue are savanna fires; and orange are small clearing and agricultural fires. Credit: NASA/D. Morton.

Sensors on NASA and NOAA satellites – including the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) – map where fires are actively burning on Earth each day. For instance, the map from NASA’s Fire Information for Resource Management System (FIRMS) below shows all of the fire detections in Bolivia that VIIRS observed on October 16, 2020.

Active fire detections in Bolivia on October 16, 2020. Credit: NASA FIRMS

But not all the red dots on the map are of equal ecological significance. As these screenshots (below) from NASA’s Amazon fire dashboard make clear, there is a lot of variety in the types of fires that have burned in Bolivia in recent months, and they vary by region and ecosystem.

Many fires in the region are short-lived grassland and savanna fires; these burn vegetation that regrows quickly, and there is usually little ecological damage and minimal carbon emissions. Likewise, many others are small-scale land clearing and agricultural fires that do not cause substantial new damage to intact tropical forests.

Fire activity in the Pando department soared in September, including significant numbers of deforestation fires. Credit: NASA Amazon fire dashboard.

On the other hand, some of those red dots are long-lasting, intense deforestation fires that were lit specifically to burn trees as part of land-clearing processes. These fires turn patches of tropical forests into pasture or cropland, fragmenting the remaining forests and altering ecosystems for decades.

Others are low-intensity understory fires that typically begin in cleared areas as agricultural fires, but then escape into neighboring forests. Even a low-intensity fire may kill half of the trees, unleashing a cascade of ecological changes that can transform tropical forests into open-canopy woodlands over time.

Savanna fires, which have been burning in sizable numbers since July, predominate in El Beni. Credit: NASA Amazon fire dashboard.

The charts above highlight the types and trends of fire type for three states (departments) in Bolivia. The northerly Pando department is still dominated by intact tropical rainforest. Satellites have detected large numbers of deforestation and agricultural fires burning there since August 2020, particularly along Highway 13. With more grasslands and fewer forests, El Beni has a higher proportion of the less-damaging fire types. The large Santa Cruz department, home to the Chiquitano dry forest and Pantanal grasslands, has comparatively large numbers of understory and grass fires.

In September and October, large numbers of fires burned in the Chiquitano dry forest, including large numbers of damaging understory fires. Credit: NASA Amazon fire dashboard.

“The goal of our new classification system is to provide real-time information on what types of fires are burning across the Amazon region every day. With thousands of individual fires burning at this point in the dry season, the question is how to prioritize regional efforts for fire suppression to best protect communities and ecosystems. Understory fires are particularly devastating in Amazon forests that are not adapted to fire,” said Douglas Morton, chief of the Biospheric Sciences Laboratory at NASA’s Goddard Space Flight Center. “However, it is worth pointing out that our real-time classification system for Amazon fires is not the only way of categorizing fires. We are working closely with state and national agencies across the Amazon to improve the classification, based on feedback from field crews.”

A map showing large fires in 2020 and their relation to key Bolivian ecosystems. Most fires have occurred in savanna grasslands, though some have burned in the wet and try tropical forests. Credit: Monitoring of the Andean Amazon

Welcome back to school!

September 9th, 2020 by Andi Brinn Thomas

School is starting and NASA’s Earth Observatory has resources for children and teachers!
EO kids logo

EO Kids – Come Explore Earth with EO Kids! Read all about different topics in NASA Earth science and try out the hands-on activities. Each issue helps students learn how NASA’s fleet of satellites help us understand and plan for our changing world. Issues are available as printable PDFs. Educators can print and distribute to students with limited access to technology. Parents can print issues for their children so they can actively learn while taking a break from screen-time. 

For students on computers, check out EO Kids videos of some of the cool activities featured in our issues. At EO Kids we are committed to making Earth science fun and engaging. Come explore our Earth with us!

Mission Biomes activity logo

Mission: Biomes – In celebration of 20 years since its first release, the Earth Observatory has updated the Mission: Biomes activity to support interactive learning and awareness of seven terrestrial biomes: rainforest, grassland, temperate deciduous forest, coniferous forest, desert, tundra, and shrubland. After reading about each biome, users can enter “The Great Graph Match” and test their biome knowledge. After mastering “The Great Graph Match”, users can enter the “To Plant or Not to Plant?” mission, read about 19 plants growing all over the world, and match those plants to the biome they prefer. Visit the Teacher Resources page to learn more about the Mission: Biomes goals, expected outcomes for students, the Next Generation Science Standards alignment, general tips for navigating the site, additional activities to learn, and more!

Earth book cover/ logo

Earth, a photo essay – NASA’s Earth is a fantastic resource for students to practice their reading skills while learning about Earth through stunning images of our planet. Through this book students appreciate science as art, part of STEAM (Science, Technology, Engineering, Art, and Math) focused curriculums.

The Earth Observatory team hopes that you all have an inspiring and informative school year!

And Then There Were Eight

April 7th, 2020 by Mike Carlowicz

There have been two rounds of voting in Tournament Earth 2020, and two rounds of stunning upsets. Only two of the top eight seeds made it through. Night Lights? Snuffed out. Colorado River? Dried up. Caspian ice? Melted. Aerosols? Cleaned out. A river of tea? Gone cold. Dark side of the Moon? Someone broke the record. Iconic Earthrise? Didn’t make it to dawn.

Every time we run one of these tournaments, we are surprised by what catches the eyes of our readers. It is time to surprise us again. Cast your votes now in round three to pick the best four of the Earthly 8. Voting ends on April 13 at 9 a.m. U.S. Eastern Time. Check out the remaining competitors below.

“Past Winners” Bracket: 
Ocean Sand, Bahamas (#5) vs. A View of Earth from Saturn (#2)

In round 1, Ocean Sand garnered the most votes overall and wiped out #4 seed and 2014 champion El Hierro Submarine Eruption, winning by the largest margin of any pairing (81 to 19 percent). In round 2, Sand beat the #1 seed, The Dark Side and the Bright Side, by a 57 to 43 percent margin. 

A View from Saturn garnered the second highest vote total in round 1, besting Blooming Baltic Sea by 77 to 23 percent. In the second round, Saturn beat Sensing Lightning from the Space Station, 60 to 40 percent. In case you didn’t notice, Earth is visible in that Saturn image.

“Home Planet” Bracket:
Twin Blue Marbles (#1) vs. Fire in the Sky and on the Ground (#7)

Twin Blue Marbles is the only #1 seed left in the tournament. In round 1, it captured 71 percent of the vote while besting Auroras Light Up the Antarctic Night. In round 2, Blue Marbles was the top overall vote getter and beat the iconic A Voyager Far from Home by 66 to 34 percent.

Fire in the Sky and On the Ground has pulled off two massive upsets. In round 1, it beat #2 seed Night Light Maps Open Up New Applications, 71 to 29 percent. In round 2, Fire beat the sentimental favorite and oldest image in Tournament Earth, All of You on the Good Earth — the original Blue Marble photo (1968) and the inspiration for the first Earth Day (1970). The voters chose the auroral fire over Apollo 8 fame by 57 to 43 percent.

“Ice and Land” Bracket:
Where the Dunes End (#8) vs. Retreat of the Columbia Glacier (#6)

This bracket pairs two low seeds that knocked off highly ranked opponents. #8 seed Where the Dunes End topped #1 A Curious Ensemble of Wonderful Features in round 1 (63 to 37 percent), then topped #4 Roiling Flows on Holuhraun Lava Field (56 to 44). 

The false-color image Retreat of the Columbia Glacier got 57 percent of the vote to beat Icy Art in the Sanikov Strait in round 1. Round 2 was a close call: Columbia barely eclipsed Antartica Melts Under the Hottest Days on Record (51 to 49 percent).

“Sea and Sky” Bracket:
Atafu Atoll, Tokelau (#8) vs. Raikoke Erupts (#6)

Another pair of Cinderella stories here. Atafu Atoll outclassed #1 seed Some Tea with Your River in round 1 by 75 to 25 percent. In round 2, it collected the second most votes overall, beating #5 Making Waves in the Andaman Sea 62 to 38 percent.

Raikoke erupted in round 1, collecting 72 percent of the vote while beating #3 Awesome, Frightening View of Hurricane Florence. In round 2, the volcanic plume smothered #2 Just Another Day on Aerosol Earth, 61 to 39 percent.

Visit this page to vote in round three.
View the full results here in bracket format.  

Getting an EPIC Perspective

March 20th, 2020 by Adam Voiland

It has been a tough month on Earth. Good news has been scarce. But here’s at least one update ― from one million miles away ― to appreciate.

The Deep Space Climate Observatory (DSCOVR) satellite, which had been out of commission for about nine months due to a technical problem, is fully operational again, according to NOAA. Issues with the satellite’s attitude control system prompted engineers to put the satellite into a “safe hold” in June 2019, but they recently developed a software fix for the problem.

And that means that the satellite’s Earth Polychromatic Imaging Camera (EPIC) is once again taking beautiful full-disk images of our home several times each day. NASA’s EPIC instrument acquired the image of Africa and Europe (above) on March 19, 2020.

Head over to the science team page for EPIC and take a few moments to savor some imagery of our ever-changing planet. If Twitter is more your style, check out @DSCOVRDaily. Look carefully and you’ll see clouds and storm fronts coming and going, plumes of dust or smoke rising and fading, and whole continents greening and browning as the seasons change.

The EPIC view is a potent reminder of something that Frank White, author of The Overview Effect, said recently on a NASA podcast. (The book explores how seeing Earth from space causes many astronauts to dramatically change their outlook on our planet and life itself.)

“[One of the] conclusions they draw is that we are really all in this together,” he said. “Our fate is bound up with people that we may think are really different from [us]. We may have different religions, we may have different politics. But ultimately, we are connected. Totally connected.”

Smoky Australian Skies

January 10th, 2020 by Adam Voiland
Credit: GLOBE Observer/Site 55HDA890077

As satellites track Australian wildfire smoke from above, GLOBE Observer citizen scientists have been keeping tabs on hazy skies from the ground.

The photograph above shows smoke blanketing Horseshoe Lagoon in New South Wales on January 6, 2020, a day when clouds limited what sensors on Terra, Aqua, and Suomi NPP could observe as they passed over.

The video below, based on photographs taken by GLOBE citizen scientist Glenn Evans, juxtaposes satellite images and photographs taken of the sky at roughly the same place and time. The contrasting perspectives underscore how easy it can be to miss the forest for the trees — or, rather, the smoke plume for the clouds — if you aren’t careful. Kristen Weaver, the deputy coordinator for GLOBE Observer, compiled the photos and matched them with the corresponding MODIS satellite images.

Victoria and New South Wales are in the midst of one of the most severe fire seasons either state has seen in decades. After months of unusually hot, dry weather, hundreds of fires have charred an area larger than West Virginia, destroying thousands of homes and resulting in dozens of deaths.

GLOBE Observer is a citizen science project that is part of the Global Learning and Observations to Benefit the Environment (GLOBE) Program. Through a free app for their mobile device, anyone in participating countries can make environmental observations of clouds, trees, land cover, and mosquito habitats that complement NASA satellite observations.

Terra Turns Twenty

December 18th, 2019 by Adam Voiland

More than 20 years ago, NASA scientist Ralph Kahn authored a column for the Los Angeles Times anticipating the launch of a new satellite — and ultimately a whole fleet of satellites — that would study Earth.

Image: Los Angeles Times/Ralph Kahn

“We want a picture of Earth that is more specific about what is happening to the climate, which after all is what makes the planet habitable,” he wrote. And that picture needed to be rich with detail. “Precisely where are deserts encroaching on grasslands? In what regions is it raining more than usual? Exactly how much are glaciers shrinking, and at what rate is the sea level rising?” he asked.

The first satellite, Terra (originally named EOS-AM), roared into space on December 18, 1999, began collecting data in February and March 2000, and collected its first complete day of MODIS data on April 19, 2000.

Image: NASA/Global Climate Change

“About every seven weeks, the satellite archives will receive as much data from EOS-AM as are held in all the volumes of the Library of Congress. And the EOS-AM satellite alone is supposed to keep pouring numbers down from the sky, relentlessly, for at least six years,” Kahn wrote.

Amazingly, all those numbers from Terra continue to pour down 20 years later. Over time, the flood of data from Terra and several other satellites has turned into scientific discoveries. Bit by bit, the questions Kahn initially posed in his column have been answered.

Image: NASA Earth Observatory based on data from Chen et al.

We can say now that sea level is rising at 3.3 millimeters (.13 inches) per year. We can show you a map of where exactly green vegetation has become more common and where it has faded. We can point you to a long-term dataset that will show you precisely where rain has fallen over the past two decades. And we can give you a tour of the world’s glaciers that shows you where they are and many examples of where they are shrinking.

The question to grapple with now: what do we with all this information?

A Second Look at Susquehanna Sediment

December 6th, 2019 by Adam Voiland
A MODIS image of the mid-Atlantic on November 6, 2019. Credit: NASA Earth Observatory

In November 2019, we highlighted this Landsat 8 image showing a glut of sediment flowing down the Susquehanna River into Chesapeake Bay. It was a striking, timely image, but one of the realities of publishing new content every day is that sometimes good information comes in after a deadline has passed.

In this case, Mark Trice, a water quality expert with the Maryland Department of Natural Resources, pointed out a few things about Susquehanna sediment after our story was out that seem worth passing on.

Mark Trice in his Maryland DNR office. The body of water on the map behind his left shoulder is Chesapeake Bay and the Atlantic Ocean. Image courtesy of Mark Trice.

Among them: a link to a recent report that synthesizes and summarizes what scientists have learned about the ecological effects of high sediment flows on the Susquehanna River and the role of the Conowingo Dam. While the dam trapped most sediment and associated nutrient pollution (nitrogen and phosphorus) when it was first built, enough material has piled up behind the dam now that significant amounts of sediment and nutrients now flow past it during storms. A University of Maryland press release summarized the findings this way:

Most sediment and particulate nutrient impacts to the Bay occur during high-flow events, such as during major storms, which occur less than 10 percent of the time. Loads delivered to the upper Chesapeake Bay during low flows have decreased since the late 1970s, while loads during large storm events have increased. Most of these materials are retained within the upper Bay but some can be transported to the mid-Bay during major storm events, where their nutrients could become bioavailable.

The potential impact of reservoir sediments to Bay water quality are limited due to the low reactivity of scoured material, which decreases the impact of total nutrient loading even in extreme storms. Most of this material would deposit in the low salinity waters of the upper Bay, where rates of nitrogen and phosphorus release from sediments into the water are low.

“While storm events can have major short-term impacts, the Bay is actually really resilient, which is remarkable,” said the study’s lead author Cindy Palinkas, associate professor at the University of Maryland Center for Environmental Science. “If we are doing all of the right things, it can handle the occasional big input of sediment.”

Trice’s colleagues at the Maryland Department of Natural Resources (DNR) underscored the Bay’s resiliency to sediment as well when I asked about the recent event. “Although these high flow events routinely occur, the Bay is resilient and continues to show improvement due to the commitment by the Bay watershed partners to have all pollution reduction strategies implemented by 2025 to have a healthy Chesapeake Bay,” said Bruce Michael of Maryland DNR.

Also worth mentioning: the 2019 water year (October 1, 2018, to September 30, 2019) brought a record-breaking flow of freshwater into the Bay, Trice noted. “The annual average freshwater flow into the Chesapeake Bay during water year 2019 was 130,750 cubic feet per second, which is the highest annual amount since 1937, the first year for which data are available,” the U.S Geological Survey said.

Chart credit: U.S. Geological Survey

Finally, thank you to Virginia Tech geology professor Brian Romans (@clasticdetritus) for pointing out something about the image that is unrelated to sediment but fascinating: the line of cities and suburbs running from Baltimore, Md., to Richmond, Va., marks the boundary between two key geologic zones: the flat Coastal Plain to the east and the more rugged Piedmont to the west. Interestingly, many cities are located along this “fall line” because rapids prevented boats from traveling any farther upstream when they were first settled.