Holuhruan: Still Erupting

November 14th, 2014 by Adam Voiland
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On September 6, 2014, the Operational Land Imager (OLI) on Landsat 8 captured this view of the eruption.

In some ways, the ongoing fissure eruption at Holuhraun lava field in Iceland is an ideal one. Unlike the lava pushing through the Hawaiian village of Pahoa, Holuhraun’s lava is nowhere near any towns or villages. And the eruption has had little effect on air traffic–unlike the Eyjafjallajokull eruption in 2010--because Holuhraun has produced little of the volcanic ash that can damage propellers and gum up engines.

What Holohruan has produced in vast quantities is lava. As a stream of eye-popping field videos—and satellite images—have shown, lava has gushed from Holuhraun almost continuously since late August. Now covering more than 70 square kilometers and filling a volume of one cubic kilometer, Holuhuraun has proven to be Iceland’s largest effusive eruption since 1784.

Holohruan also has been a reliable source of sulfur dioxide, a colorless but toxic gas present within magma. In addition to triggering health problems if inhaled, sulfur dioxide can lead to acid rain and it can react with other substances in the air to produce sulfate aerosols that cool the atmosphere by deflecting sunlight.

Fossil-fuel burning releases sulfur dioxide, but volcanoes do so on a grander scale. Nature reported that an average of 35 tonnes of sulfur dioxide are streaming from Holohuraun each day, more than twice the amount that all of Europe’s factories produce in the same period. “Those levels of sulfur dioxide emissions are quite typical—even low—for an erupting volcano,” said Simon Carn, a volcanologist at Michigan Technological University. “The most interesting aspect of the Holuhruan eruption is its duration. It could go on from months, so the total sulfur dioxide emissions could end up being large.”

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For a sense of the daily ebb and flow of sulfur dioxide emission, see the chart above, which is based on observations from the Ozone Monitoring Instrument (OMI) on NASA’s Aura spacecraft. The image below shows OMI’s observation of a sulfur dioxide plume drifting over Iceland on September 4, 2014, one of the days the sensor observed a peak in sulfur dioxide emissions. High concentrations of sulfur dioxide are shown in red.

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In at least one case, gases from Holuhruan have entered the atmosphere with remarkable style. On September 3, engineers with Nicarnica Aviation were monitoring the eruption from the ground with an infrared camera. The camera is designed to detect ash, but they ended up capturing a view of something unusual: a spiraling plume that was likely dominated by sulfur dioxide and other gases. The structure was reminiscent of a dust devil, a small, rotating column of air that forms when one part of a surface heats up much faster than the surrounding area.

In the video below, colors correspond to the temperatures observed by the camera. Red depicts the hottest temperatures, yellow moderate temperatures, and blue the coolest. “The general mechanism is probably the same as that for dust devils, but in this case the funnel is most likely filled with sulfur dioxide, gas, and volcanic ash,” Prata told New Scientist.

Earth’s Disappearing Groundwater

November 5th, 2014 by Adam Voiland

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Maybe you have heard people call Earth “the water planet.”  The nickname is well-deserved. As this mosaic of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite conveys so well, the majority of Earth’s surface is covered by either liquid or frozen water.  The atmosphere is awash with water as well. One satellite-based data set estimates that about 60 percent of Earth’s surface is covered by clouds (composed of water and ice droplets) at any given time.

Earth is home to yet another type of water—groundwater—which includes all the fresh water stored underground in soil and porous rock aquifers. Though groundwater is often forgotten because it’s not visible, more than two billion people rely on it as their primary water source. 

With drought afflicting several parts of the world, and with aggressive use of groundwater in many agricultural regions, this precious water resource is under serious strain, warns NASA Jet Propulsion Laboratory hydrologist James Famiglietti. In a commentary published by Nature Climate Change in October 2014, Famiglietti wrote:

In many parts of the world, in particular in the dry, mid-latitudes, far more water is used than is available on an annual, renewable basis. Precipitation, snowmelt, and streamflow are no longer enough to supply the multiple, competing demands for society’s water needs. Because the gap between supply and demand is routinely bridged with non-renewable groundwater, even more so during drought, groundwater supplies in some major aquifers will be depleted in a matter of decades. The myth of limitless water and the free-for-all mentality that has pervaded groundwater use must now come to an end.

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Image by J.T. Reager, NASA Jet Propulsion Laboratory.

Most of the major aquifers in the world’s arid and semi-arid zones—the parts of the world that rely most heavily on groundwater—are experiencing rapid rates of depletion because of water use by farms. As shown in the chart above—based on data collected by the Gravity Recovery and Climate Experiment (GRACE)—this includes include the North China Plain, Australia’s Canning Basin, the Northwest Sahara Aquifer System, the Guarani Aquifer in South America, the High Plains and Central Valley aquifers of the United States, and the aquifers beneath northwestern India and the Middle East.

The situation is looking particularly grim in California, a state currently suffering from extreme drought. The extent of the drought is visible in the series of GRACE maps of dry season (September-November) water storage anomalies shown below. Red areas show the height of the water in comparison to a 2005-2010 average. California’s Sacramento and San Joaquin river basins have lost roughly 15 cubic kilometers (4 cubic miles) of total water per year since 2011 — more water than all 38 million Californians use for domestic and municipal supplies annually. Over half of the water losses are due to groundwater pumping in the Central Valley, according to Famiglietti.

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Image by Felix Landerer, NASA Jet Propulsion Laboratory.

The first step to managing the globe’s groundwater problem is to accept that we have one, Famiglietti recommends. And when societies are ready to look for solutions, the first place they’ll have to turn is the agricultural sector. “Agriculture accounts for nearly 80 percent of water use globally, and at least half of the irrigation water used is groundwater,” he wrote. “Even modest gains in agricultural efficiency will result in tremendous volumes of groundwater saved, or of water available for the environment or other human uses such as municipalities, energy production, industry and economic growth.”

Read the full commentary here.  You can read news reports about Famiglietti’s article from Mashable, the Financial Times, and Discovery News. Read more about observing groundwater from space in “The Gravity of Groundwater.” Watch Famiglietti give a TEDx talk about groundwater losses below.

October Puzzler Answer: Kansas City

October 27th, 2014 by Kathryn Hansen

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Congratulations to Deanne Howard, who was the first to solve our October 2014 puzzler. The answer is Kansas City, which as many readers pointed out is located in both Kansas and Missouri. We decided to award the win to the first person to correctly guess the city name, regardless of whether the answer specified a state.

North is to the upper right in this image, which was taken on September 6, 2014, by astronauts on the International Space Station. Charles B. Wheeler Downtown Airport is a distinct landmark, located inside the bend of the Missouri River. Southeast of the river confluence (off the bottom of this photograph), the Kansas City Royals faced the San Francisco Giants in baseball’s 2014 World Series at Kauffman Stadium. Read more about this Image of the Day published on October 24, 2014.

We extend a special thank you to Lynne Beatty, Daniel Hogan, Mary Mathews, DJ Bailey, Ryan Wilson, David M., hai On, Gaye Hattem, and others who shared extra insight about the scene in the comments section of the puzzler’s original blog post, and to Ken Hammond for the nod to the area’s history on Facebook.

October Puzzler

October 20th, 2014 by Kathryn Hansen

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Every month on Earth Matters, we offer a puzzling satellite image. The October 2014 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!

September Puzzler

September 29th, 2014 by Adam Voiland

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UPDATE (October  3, 2014) – The answer to this puzzler was posted here.

Every month on Earth Matters, we offer a puzzling satellite image. The September 2014 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!

Help Us Make a Satellite Version of the ABCs

September 26th, 2014 by Adam Voiland

As a side project, I have been filing away images to make a satellite version of the ABCs. I have most letters now, but I could still use help tracking down good examples of B, G, F, K, and Z. Since I first posted about the search, there is a new browsing tool available — called Worldview — that I highly recommend. Once you navigate to the site, just make sure you have a MODIS true color layer (either Aqua or Terra) turned on, and you can quickly start browsing for cloud formations, dust storms, smoke plumes, and much more.

When you find a letter, click the permalink button on the upper right (it looks like two links of a chain), and then post the url in the comments section below. Another great place to look is the astronaut Earth from Space gallery curated by the Johnson Space Center. The “Earth-Human Interactions” section might be especially useful for finding the straight lines needed for an upper case F, K, or Z. Though I am still missing those five letters, feel free to send any you find. Perhaps you’ll find a better example than what I already have. Good luck and happy hunting!

As a preview, here is the C and the D that I have filed away. The C is an artificial island off the southern end of Bahrain Island. The D is a rotated view of Akimiski Island in Canada’s James Bay.

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Science Cover_GRACE

Drought-induced depletion of groundwater is no longer an issue that’s out of sight, out of mind.

Research by scientists from Scripps Institution of Oceanography, published this week in Science, describes a GPS technique used to measure drought-induced uplift of land in the western United States. The uplift measurements were used, in turn, to calculate the deficit in surface and near-surface water for the area, which they estimated for March 2014 to be 240 billion tons. That’s equivalent to a 4-inch-thick layer (10 centimeters) of water over the region, or the current annual mass loss from the Greenland Ice Sheet.

GPS is not the only way to measure land displacement caused by the loss of ground and surface water. Scientists have long used the Gravity Recovery and Climate Experiment (GRACE) satellites to estimate groundwater depletion around the planet, as noted by Marcia McNutt in a related editorial.

GRACE’s achievements even graced the cover of the same issue of Science (pictured above). The image shows California’s loss of fresh water (red) from 2002 through 2014. Drought has drained the region of more than 3.6 cubic miles (15 cubic kilometers) of fresh water in each of the past three years.

The image was updated from a version that initially appeared alongside research in 2013 by James Famiglietti of NASA’s Jet Propulsion Laboratory and University of California, Irvine, and Matthew Rodell of NASA’s Goddard Space Flight Center.

Read more to learn about how GRACE is used to view Earth’s water supplies, or how U.S. groundwater on July 7, 2014, compared to the average from 1948 to 2009.

NASA Earth Science in the News

September 16th, 2014 by Patrick Lynch

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These images compare averaged yearly nitrogen dioxide concentrations over the Ohio River Valley region from 2005 [top] to 2011 [bottom]. Image credit: NASA Goddard’s Scientific Visualization Studio/T. Schindler

Editor’s Note: This is an excerpt from the NASA Earth Science in the News column published in the May/June issue of The Earth Observer newsletter. You can download the current issue here.

See NASA’s Dazzling Proof that U.S. Air Quality Has Improved, Mashable.com. Summer in the U.S. is the time of year when humidity skyrockets, air stagnates, and the air quality deteriorates, especially downwind of the coal-fired power plants and manufacturing plants of the Ohio Valley. During hazy and hot summer days in the big cities along the Interstate 95 corridor, the sky often looks like the visual equivalent of white noise—with the horizon indistinguishable from the milky sky. Yet air quality has actually been steadily improving over the past few years, largely thanks to the Clean Air Act, along with a drop in coal use and dramatic changes in vehicle fuel efficiency and emissions. NASA has released beautiful images demonstrating that people in major U.S. cities from Los Angeles to New York are breathing less nitrogen oxide. The data come from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite. Nitrogen dioxide is one of the six common pollutants the EPA regulates to protect human health. It can harm the respiratory system and also combines with other pollutants to form smog. Nitrogen dioxide is mostly produced by burning gasoline in vehicle engines and from burning coal. “While our air quality has certainly improved over the last few decades, there is still work to do—ozone and particulate matter are still problems,” said atmospheric scientist Bryan Duncan.

Water Weight Used to Calculate the Amount of Snow in California with GPS, Scientific American. Water weighs about 8.3 pounds per gallon (1 kg/L). Now, scientists have developed a way to use water’s weight to measure just how much snow is covering mountains in the western U.S. In states like California, currently in the midst of a crippling drought, the more water managers know about how much snow is in the mountains, the better they can plan for the summer months ahead. More accurate information about such snowpack can help these managers and hydrologists plan for how to fill reservoirs, how much water they might have available during the dry season, and how dry the soils might be during fire season. They’ll also get a better fix on future levels of reservoirs for hydroelectric power generation. Donald Argus, a research scientist and geophysicist at JPL, recently published a study outlining the new technique in the journal Geophysical Research Letters. If scientists know the height of a piece of land in summertime, and the height when snow covers it, they can use the difference to calculate how much snow is sitting on the mountains. The technique uses a dense network of global positioning system (GPS) sites scattered across the Western U.S.

Scientists Warn of Rising Oceans From Polar Melt, The New York Times. A large section of the mighty West Antarctica ice sheet has begun falling apart and its continued melting now appears to be unstoppable, two groups of scientists reported on May 12, 2014. If the findings hold up, they suggest that the melting could destabilize neighboring parts of the ice sheet and a rise in sea level of 10 feet (about 3 meters) or more may be unavoidable in coming centuries. Global warming caused by the human-driven release of greenhouse gases has helped to destabilize the ice sheet, though other factors may also be involved, the scientists said. The rise of the sea is likely to continue to be relatively slow for the rest of the twenty-first century, the scientists added, but in the more distant future it may accelerate markedly. The West Antarctic ice sheet sits in a bowl-shaped depression, with the base of the ice below sea level. Warm ocean water is causing the ice sitting along the rim of the bowl to thin and retreat. As the front edge of the ice pulls away from the rim and enters deeper water, it can retreat much faster than before. In a new paper published in Geophysical Research Letters, a team led by glaciologist Eric Rignot used satellite and airborne measurements to document an accelerating retreat of six glaciers draining into the Amundsen Sea region. With updated mapping of the terrain beneath the ice sheet, the team was able to rule out the presence of any mountains or hills significant enough to slow the retreat.

NASA Places Radar in North Carolina to Study Rain in Smokies, Washington Times. NASA placed two radars on land in Rutherford County, North Carolina, for a field campaign to study rainfall in the Great Smoky Mountains. The campaign ran from May 1 to June 15, 2014. “We have set up rain gauges and radars across the area to learn more about how weather and rain systems behave in the mountains,” said research scientist David Wolff. The campaign was designed to validate data from the Global Precipitation Measurement (GPM) mission’s Core Observatory, which launched in February 2014. The science team expected to end the six-week campaign with detailed data to improve their understanding of both the fundamental sciences of mountain rainfall and how best to estimate rainfall using satellite observations over remote and rugged regions. Scientists will use what they learn to improve weather predictions and flood warnings. Team members will take a break after the summer and are scheduled to travel to Seattle, Washington, in 2015-16 to measure winter weather there.

NASA ‘Balloon Campaign’ Goes to Australia, International Business Times. NASA and the University of Wyoming teamed up with the Australian Bureau of Meteorology (BOM) in Darwin, Australia, for a balloon-based campaign designed to better understand the composition and behavior of volcanic plumes. The Kelud Ash (KlAsh) experiment involved launching a series of balloons to take measurements of emissions from the volcano in Indonesia. Mt. Kelud sent small droplets of sulfuric acid—as ash particles and sulfate aerosol—up to 15 mi (25 km) above Earth when it erupted in February this year. Principal investigator Duncan Fairlie said: “The purpose is to better characterize particle sizes, composition, and optical properties from a relatively fresh volcanic plume in the stratosphere.” The two-week balloon campaign, which started on May 14, 2014, launched small balloon payloads over the Indian Ocean from the bushes of Darwin territory. Fairlie said the team sampled the volcanic plumes at an altitude of around 12 miles (20 kilometers) in all flights.

Puzzling Evidence

September 2nd, 2014 by Mike Carlowicz

The answer to the August puzzler — Nagoya and the south-central coast of Japan — was puzzling even to Earth Observatory staff.

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When we first posted the image on August 26, even we did not know what we were looking at. We had asked our colleagues at the Crew Earth Observations (CEO) office at NASA Johnson Space Center to give us an image that would stump our readers and would help us talk about a new citizen science project to identify the locations shown in nighttime images. They gave us an image that no one here immediately recognized.

In the process of presenting the answer last Friday (image below), we unwittingly demonstrated a quality-control portion of that ID program.

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As you can see, we correctly labeled Nagoya, and then labeled the two cities on the left as Osaka and Wakayama. But as several readers from Japan pointed out, Osaka and Wakayama are farther west, and Kyoto also appears in the scene. Though we had consulted two different sources, maps of Earth at night are still pretty raw and the human eye can be tricked when looking at an unfamiliar landscape.

One of the protocols of the Cities at Night program is to ensure that every image is classified by multiple individuals working separately. It took several NASA staff and several readers to figure out the correct locations in this image. One of the goals of the citizen-science project is to figure out the optimal number of people needed to correctly classify an image. We didn’t intend to be a case study, but that’s what just happened.

Congratulations to Bruce Boucek, a data librarian at Brown University, for being the first reader to correctly identify Nagoya and the Chita peninsula of Japan. We asked him how he figured out the location, and he wrote: “I’ve been a map fanatic since I was a kid…When I was an undergrad, I had a particular interest in Japanese geography and as a PhD student I spent years working with remote sensing and satellite imagery. My initial hunch was that it was the eastern coast of Japan, but it didn’t look like Tokyo. I guessed that it was the next bay south and verified my hunch by looking at the NASA earth at night imagery. The clincher was the airports which have a significantly higher brightness signature.”

Three other readers — James Titmas, Jyo Sano, and Yumiko Stettler — also correctly identified the Nagoya area. Thanks also to Justin Wilkinson, Will Stefanov, and the CEO unit at NASA Johnson, a team that has to catalog and identify the thousands of images that come down from the International Space Station every year.

August Puzzler

August 26th, 2014 by Mike Carlowicz

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Every month on Earth Matters, we offer a puzzling satellite image. The August 2014 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.

 

UPDATE (September 4) – The answer to this puzzler was the Image of the Day on August 31. We also posted a blog entry about the challenges in solving this puzzler.