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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A Grim Visit to a Marine Mammal Hospital

February 29th, 2016 by Adam Voiland


While I was in San Francisco in the fall of 2015, I headed across the Golden Gate Bridge to take a tour of The Marine Mammal Center, a nonprofit veterinary research hospital in Sausalito, California. I had heard that a blob of unusually warm water off the Pacific coast had taken a toll on marine life and caused an increase in the number strandings.

When I visited on December 16, 2015, the hospital was taking care of 81 northern fur seals, 7 California sea lions, 1 northern elephant seal, and 1 Guadalupe fur seal. That is a lot of northern fur seals—three times more than the center rescued the previous year and more than twice the previous record, which was set in 2006.

While sea lions, elephant seals, and Guadalupe fur seals were scarce when I visited, had I come earlier in the year there would have been plenty of these species as well. By February 2015, the center had rescued record numbers of starving sea lion pups; by April, they were dealing with record numbers of elephant and harbor seals; by June, they had taken in five times the normal number of Guadalupe fur seals.


A northern fur seal resting on a warming mat. Photo by Adam Voiland.

The photograph above shows one of the northern fur seals resting on a warming mat. “Northern fur seals are smaller, furrier and feistier than the California sea lion pups we rescued earlier this year,” noted Shawn Johnson, the director of veterinary science at The Marine Mammal Center, in a November press release. “But otherwise the scene here is the same—our rescue trucks continue to arrive day after day with more starving pups in need of our care.” By the end of the year, the center had rescued 1,800 animals, breaking nearly every record in the facility’s 40-year history.

What was causing all of the trouble? Most marine scientists think the warm water blob in the northeast Pacific was a key culprit. The warm water was driven by the emergence of an unusually strong and persistent ridge of atmospheric high pressure in the northeastern Pacific Ocean. The feature, which was so unrelenting that meteorologists took to calling it the Ridiculously Resilient Ridge, weakened winds in the area enough that the normal wind-driven churning of the sea eased.

Those winds usually promote upwelling, which brings deep, cool water up toward the surface; instead, the resilient ridge shut down the ocean circulation, leaving a large lens of unusually warm surface water in the northeastern Pacific. Upwelling brings dissolved nutrients to the surface, so the slowdown in upwelling meant many animals had less to eat. In addition, the warm water extended the time that  certain type of algae bloom produced toxins that can cause serious health problems for marine mammals.


The maps below show sea surface temperature anomalies in the Pacific in July 2015. Large patches of warm water dominated the Gulf of Alaska and along the California coast. The map is based on data collected by the U.S. Navy’s WindSAT instrument on the Coriolis satellite and the AMSR2 instrument on Japan’s GCOM-W. Note that the maps do not depict absolute temperatures; instead, they show how much above (red) or below (blue) water temperatures were compared to the average from 2003 to 2012.

The good news it that the blob has finally broken up. By January 2016, more seasonable temperatures had returned to the northeast Pacific, thanks to the strong El Niño in the equatorial Pacific. The breakup of the warm blob came as no surprise to weather watchers. In September 2015, Clifford Mass, a University of Washington atmospheric scientist, explained in his blog that El Niño generally brings lower-than-normal sea surface pressures to the eastern Pacific—the opposite of the systems that sustained the blob. By mid-December 2015, around the time that I was visiting the Marine Mammal Center, Mass declared that the blob was dead.

However, remnants of the warm blob still persist. “There are significant temperature anomalies extending down to a depth of about 300 meters. So while the weather patterns the past few months have not been that favorable to warming, it will take a while for all of the accumulated heat to go away,” explained Nicholas Bond, a University of Washington meteorologist and Washington state’s climatologist. That means impacts on marine life and on weather in the Pacific Northwest could linger, though Bond does not think the blob will return in the near term.

The type of type of algae that has caused harmful blooms is Pseudonitzschia, which produces the neurotoxin domoic acid. The Marine Mammal Center is where scientists first discovered (in 1998) that domoic acid could be toxic to marine mammals. The toxin accumulates in shellfish, sardines, and anchovies, common food sources for marine mammals. Exposure to domoic acid affects the brains of mammals; it can cause them to become lethargic, disoriented, and have seizures that sometimes result in death.

High levels of domoic acid likely contributed to the record number of marine mammal strandings. Since the toxin can also affect humans and was found in the meat of commercial fish and crabs (rather than just the guts), authorities also closed major fisheries including Dungeness and rock crab, anchovy, oyster, razor clams, and mussels in 2015.

In many areas, domoic acid remained a concern in mid-February 2016. Though the situation has improved somewhat, California’s commercial dunegrass crab season will remain closed until more of the coast is clear of the toxin, according to the San Francisco Chronicle.


Meanwhile, National Oceanic and Atmospheric (NOAA) scientists recently reported that domoic acid is present in Alaskan marine food webs in high enough concentrations to be detected in marine mammals such as whales, walruses, sea lions, seals, porpoises and sea otters. “Since 1998, algal toxin poisoning has been a common occurrence in California sea lions in Central California. However, this report is the first documentation of algal toxins in northern ranging marine mammals from southeast Alaska to the Arctic Ocean,” a NOAA press release said.

“We do not know whether the toxin concentrations found in marine mammals in Alaska were high enough to cause health impacts to those animals. It’s difficult to confirm the cause of death of stranded animals. But we do know that warming trends are likely to expand blooms, making it more likely that marine mammals could be affected in the future,” NOAA research scientist Kathi Lefebvre said.

For more details about the unusual conditions in the Pacific Ocean, see this story from the University of California.

February Puzzler

February 24th, 2016 by Adam Voiland


Every month on Earth Matters, we offer a puzzling satellite image. The February 2016 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, what the image shows, 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 about the geological, meteorological, or human processes that have played a role in molding the landscape. Please include your preferred name or alias with your comment. If you work for or attend 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 day to give others a chance to play.

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

Good luck!


Oreopoulos explains cloud optical thickness in front of the NASA hyperwall. Photo courtesy of L. Oreopoulos

Earth Matters occasionally publishes interviews with NASA earth scientists from around the agency. Here we feature Lazaros Oreopoulos, chief of the Climate and Radiation Laboratory at Goddard Space Flight Center.

Can you describe your job?
I have three roles. For the last two-and-a-half years, I’ve been the chief of the Climate and Radiation Lab, so that makes me a first-line supervisor. I manage the affairs of the lab of about 70 people that I joined in 1997.

I’m also deputy project scientist of the Aqua mission. Aqua was launched in 2002 as part of the Earth Observing System missions. Aqua measures various atmospheric, land surface, ocean and ice properties.

My third role is as a scientist studying the interaction of clouds with atmospheric radiation. I use satellite observations to understand cloud properties explaining the role of clouds and climate. I’m also trying to improve cloud representation in global climate models.

Clouds are notoriously hard to study. They come in so many different shapes, sizes and internal structures. A major question is how clouds will impact future climate change, whether they will mitigate or enhance the rate of change. We don’t have a long enough record of how clouds may have changed over the years to help us answer this question. It is challenging to reconstruct the record backwards, but satellite observations are the best way to construct records from the recent past forward.

map shows an average of all of the satellite’s cloud observations between July 2002 and April 2015. Colors range from dark blue (no clouds) to light blue (some clouds) to white (frequent clouds). NASA Earth Observatory images by Jesse Allen and Kevin Ward, using data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center.

This map shows an average of all Aqua MODIS cloud observations between July 2002 and April 2015. Colors range from dark blue (no clouds) to light blue (some clouds) to white (frequent clouds). Read more about the image here. NASA Earth Observatory images by Jesse Allen and Kevin Ward, using data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center.

What makes your lab unique?

Our lab is an international group of scientists with various backgrounds who are all top experts in their fields. Most of our civil servant scientists were not born in the U.S. Many of them came to Goddard via a complicated, difficult path. Some survived the dissolution of their countries’ governmental systems. Another lived through a civil war during his childhood. As a result, little problems don’t scare or phase them. Their strong character puts everything in perspective because they have been through much worse. It makes them persevere and be persistent. They are also very, very happy to be here with all the means available to do what they love.

Our winter party celebrating the new year has a strong international flavor. We have a potluck party where people bring dishes representing the cuisine of their home countries. The accompanying slideshow with photos from their travels or youth years is quite entertaining.

Our group really doesn’t think about ethnic differences; we understand that we live in an international environment and are always accepting of cultural differences. Our party is one more opportunity to share experiences and backgrounds.

How do you keep such an international group moving in the same direction?

We have a lot of strong personalities, which is an asset. We try to stay focused on the science and our overarching goal, which is to fulfill our mission. We won’t stop until we’ve accomplished our goal.

Montreal at night on December 24, 2010. The image was taken on the International Space Station by Expedition 26 crew. Read more about the image here.

Montreal at night. This photograph was taken from the International Space Station by Expedition 26 crew. Read more about the image here.

Please tell us about your international background.

I have lived in four countries. I speak Greek, English, French and German.

I was born in a small Bavarian town in Germany close to the Austrian border near Salzburg. My parents were poor Greeks who immigrated in the ’60s seeking a better life. We returned to Greece when I started school. I went to Aristotle’s University in Thessaloniki, Greece, eventually majoring in physics. I then went to McGill University in Montreal, Canada, earning a doctorate in atmospheric sciences. A year later, I came to Goddard as an atmospheric scientist.

Living in four countries gave me a variety of experiences and professional interactions. Not only is my lab international, but the research and science communities at large are international as well.

Why did you become an atmospheric scientist?

I was always interested in the mysteries of weather. Every day changes fascinated me. Seasons intrigued me. As an undergraduate, I met some professors who were atmospheric scientists and they encouraged me to do extra work to delve deeper into the topic. I also thought that job prospects were better for an atmospheric scientist than for other disciplines in physics.

Conversations with Goddard - Lazaros Oreopoulos

Lazaros Oreopoulos. Photo by W. Hrybyk (NASA).

What was your proudest moment at Goddard?

My proudest day was the day I was deemed worthy to lead a lab. I was excited and intimidated at the same time.

What do you do outside Goddard?

I like listening to indie rock music, which is contemporary rock outside the major label circuit. My combined physical and digital music collection exceeds 5,000 albums. I tried playing guitar, but wasn’t very good at it. I’m now encouraging my young son to learn for both of us.

As a mentor, what advice to you give?

Within my laboratory, I personally work with five young scientists who help advance my research projects. I urge them to be passionate about the science, come up with original ideas and work hard.

I also tell them it is very important to learn to communicate their science effectively. I advise them how to get their message across in their writing and oral presentations. You first have to believe in your research project, that’s the start of being appealing as a scientist. Not everyone is very charismatic, you either are or you’re not, but you can learn to overcome a charisma deficiency. Everyone can learn to effectively communicate their science. I try to teach them to be concise and highlight what is important. I encourage them, as well as others in my lab, to attend workshops on how to present and write better.

What is the one thing you would tell someone just starting their career at Goddard?

I’d tell them that they are in one of the best places in the world to work in science and engineering. I’d tell them to focus on the fun and exciting aspects of their work and not worry about small, daily issues. Minor problems don’t change the fact that we are at Goddard and lucky to have this opportunity. So, I’d remind them to always focus on the big picture and what matters most.

What is it like being married to another researcher?


This astronaut photograph shows much of the nation of Greece. The Peloponnese—home in ancient times to the city-state of Sparta—is the great peninsula separated from the mainland by the narrow isthmus of Corinth. Read more about this image here.

My wife is an M.D.-Ph.D. at the National Human Genome Research Institute of the National Institutes of Health. We occasionally discuss our respective research. Since we are both scientists, we understand each other’s work demands and that there will be periods of intense work where we need to support each other. We have one child still at home so we have to creatively juggle caring for him along with our other domestic responsibilities. Every year we struggle to find mutually available days to take a family vacation. My wife was also born in Greece, so we try to go back to Greece every year. We are glad to see that our son is also showing an inclination towards mathematics and science, but will of course let him choose his own path.

This interview was originally published by Goddard Space Flight Center. 

January Puzzler Answer: Palau’s Coral Reefs

February 18th, 2016 by Adam Voiland


Congratulations, Thomas Goldammer, for being the first to solve our January Puzzler. As Thomas noted, the image highlighted coral reefs immediately north of Palau’s Babeldaob island. Tyler Johnson chimed in the next day with some additional details and insight.

Though more than 100 people weighed in on Facebook, reefs in Palau never came up. Interestingly, several Facebook readers guessed that the image showed reefs in the Maldives. That, in turn, reminded me of an old but excellent story in our archives about the amazing atolls in the Maldives. The story does a nice job of explaining how atolls (such as the the North and South Malosmadulu Atolls shown below) get their remarkable shapes.


As our atoll article explains, the shapes of Maldavian atolls are affected not only by the birth and death of islands but also by the churning and currents of the ocean caused by the winds of passing monsoons. (Extraordinary, isn’t it? Maybe it is just me, but I find understanding how the land surfaces came to be both fascinating and humbling.)

Getting back to Palau, I also want to draw your attention to the video below. Compiled by the Khaled bin Sultan Living Oceans Foundation, it shows mesmerizing aerial and underwater imagery of Palau’s reefs. In fact, the foundation recently completed an expedition to Palau to collect baseline data on the health of the reefs. Ground campaigns like this—combined with aerial and satellite campaigns from above—offer scientists a more  complete picture of the health of the world’s coral reefs than either might along. To learn more about a NASA-sponsored aerial survey of Palau’s coral reefs, see our January 31 Image of the Day.