AGU 2014: Urban Areas as Seen from Space

December 18th, 2014 by Kathryn Hansen

The 2014 fall meeting of the American Geological Union (AGU) is more than halfway over. Throughout the week we’ve been enjoying a series of cartoons drawn live at the meeting by Miles Traer, a multimedia producer at Stanford’s School of Earth Sciences, inspired by various sessions. Below is a cartoon from December 16 titled: “Atlas of Global Urban Change, a compendium of Earth’s rapid urbanization.” See the full collection here.

Urban Change Atlas_0 copy

Also on December 16 at AGU, scientists presented images demonstrating an aspect of urbanization that appeared less like a cartoon and a bit more festive. The images showed that city lights shine brighter during the holidays in the U.S. when compared with the rest of the year. In central urban areas, brightness was shown to increase by 20 to 30 percent, while suburbs and outskirts of major cities saw light intensity increase by 30 to 50 percent. Read more about the holiday lights images here and here.

IDL TIFF file

Picturing Science: December 17, 2014

December 17th, 2014 by Adam Voiland

Nighttime lights around many major U.S. cities shine 20 to 50 percent brighter during Christmas and New Year’s when compared to light output during the rest of the year.  Full story. Related.

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Kilauea lava flow burning through forest near Pahoa, Hawaii. Full story. Related.

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Yes, that’s a NASA plane without wings. Its top speed: 1,064 miles per hour. (Mach 1.6).  Full story.

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We like to show you snazzy pictures from the field and from space, but this is what science really looks like. AGU 2014 is on. Full story. Related.

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The occurrence of summertime fog in the eastern Pacific declined by 33 percent over the course of the 20th century, a recent study found. Full story. Related.

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“Any thunderstorm can produce gamma rays, even those that appear to be so weak a meteorologist wouldn’t look twice at them,” said Themis Chronis of the University of Alabama. Full story. Related.

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“Venus sits in the background of the Earth’s atmosphere.” — Via @AstroTerry.  Original Tweet.

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AGU 2014: The Buzz

December 16th, 2014 by Kathryn Hansen

A record 25,000 researchers and exhibitors descended on San Francisco this week for the 2014 meeting of the American Geophysical Union (AGU). That number of attendees translates to a tremendous amount of Earth science being discussed via presentations and posters, and we can’t possibly cover it all in this blog. Fortunately, this buzz word graphic posted by @AGU_Eos helped us sort what attendees are talking about, at least on twitter at #AGU14.

agu buzz words

Drought was certainly a hot topic, particularly California’s multi-year episode. NASA scientists announced at a press briefing that it would take about 11 trillion gallons of water (42 cubic kilometers)—or 1.5 times the maximum volume of the largest U.S. reservoir—to recover from the current drought. The calculation, based on data from the Gravity Recovery and Climate Experiment (GRACE) satellites, is the first of its kind. Read the full story here.

The buzz word “ice” probably stems from the abundance of research on Greenland that was presented on December 15. Scientists using ground-based and airborne radar instruments found that liquid water can now persist throughout the year on the perimeter of the ice sheet; it might help kick off melting in the spring and summer. Read more about those studies here. Look, too, at this new study that used satellite data to get a better picture of how the ice sheet is losing mass.

And finally, take a minute to browse some of the cool photos presented by Anders Bjørk of the Natural History Museum of Denmark, which included the portrait of Arctic explorers (below) and this image pair demonstrating glacial retreat in Greenland.

Arctic-History

NASA Earth Science in the News

December 10th, 2014 by Patrick Lynch

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

America’s Tiny Four Corners Region is an Outsized Methane Hotspot; TIME.com. One small spot in the U.S. Southwest is surprisingly the producer of the largest concentration of methane (CH4) gas seen across the nation. Levels of CH4 over the Four Corners region are more than triple the standard groundbased estimate of the greenhouse gas, as reported in a point study of satellite data by scientists at NASA/Jet Propulsion Laboratory (JPL) and the University of Michigan. CH4 is a heat-trapping gas whose increasing quantities in the atmosphere have fueled concerns about global climate change. The methane “hotspot,” seen on the map as a small splotch—see map above—measures approximately 6475 km2 (2500 mi2) at the junction of Arizona, New Mexico, Colorado, and Utah. For scale, the state of Arizona is about 292,668 km2 (113,000 mi2). But the area generated an annual 0.59 million metric tons of methane between 2003 and 2009—about as much CH4 as the entire coal, oil, and gas industries of the U.K. give off each year.

The Four Corners area (red) is the major U.S. hot spot for methane emissions in this map showing how much emissions varied from average background concentrations from 2003-2009 (dark colors are lower than average; lighter colors are higher). Image Credit: NASA/JPL-Caltech/University of Michigan

 

Scientists Say Ozone Layer is Recovering; Associated Press. Earth’s protective ozone layer is beginning to recover from its previously reduced levels, largely because of the phase-out since the 1980s of certain chemicals used in refrigerants and aerosol cans, a U.N. scientific panel reported. Scientists said the development demonstrates that when the world’s peoples come together, we can counteract a brewing ecological crisis. For the first time in 35 years, scientists were able to confirm a statistically significant and sustained increase in stratospheric ozone, which shields the planet from solar radiation that causes skin cancer, crop damage, and other problems. From 2000 to 2013, ozone levels climbed 4% in the key mid-northern latitudes at about 48 km (30 mi) above Earth’s surface, said scientist Paul Newman [NASA’s Goddard Space Flight Center (GSFC)].

Deep Ocean Hasn’t Warmed Measurably in a Decade, Says NASA; The Weather Channel. Deep below the ocean surface, there’s a place global warming hasn’t yet reached. According to a study published on October 5, 2014, in Nature Climate Change, scientists at NASA/Jet Propulsion Laboratory (JPL) have found that over the last decade the deepest part of the world’s ocean has not warmed measurably. The scientists analyzed ocean temperatures from between 2005 and 2013 and found that below a depth of approximately 2 km (~1.2 mi)—roughly halfway to the bottom at this location—the global ocean has not warmed nearly as quickly as the top half. The scientists collected the temperature data using both satellite measurements and data from the Argo array, a network of some 3500 floating probes scattered throughout the world that measure ocean temperatures and salinity. “The sea level is still rising,” said study coauthor Josh Willis [JPL] in a news release. “We’re just trying to understand the nitty-gritty details.”

Antarctic Sea Ice Level Breaks Record, NASA Says; CBSNews.com. Sea ice surrounding Antarctica is at an all-time high, even as global temperature averages continue to climb. NASA reports that ice formation in the continent’s southern oceans peaked this year, breaking ice-measuring satellite records dating back to the late 1970s. For the first time since 1979, on September 19, 2014, Antarctic sea ice extent exceeded ~20 million km2 (~7.7 million mi2) whereas the average maximum extent between 1981 and 2010 was ~19 million km2 (~7.3 million mi2). Despite this trend, sea ice as a whole is decreasing on a global scale. Researchers say that, just like global warming, trends have different outcomes in different parts of the world; not every location with sea ice will experience ice loss or gain. “When we think about global warming we would expect intuitively that ice should also be declining in the Antarctic region as in the Arctic,” explained senior research scientist Josefino Comiso [GSFC]. “But station and satellite data currently show that the trends in surface temperatures are most positive in the Arctic, while in the Antarctic region the trends are a mixture of positive and negative trends,” he said, adding that cooling and declining sea surface temperatures could also contribute to a “more rapid advance at the ice edge.”

1934’s Dust Bowl Drought Was the Worst in a Thousand Years for U.S.; NBCNews.com. The drought of 1934 wasn’t just bad, it was the worst. That’s the finding of a reconstruction of North American drought history over the past 1000 years, done by scientists from NASA and Columbia University’s Lamont-Doherty Earth Observatory. Their study, published in the October 17 issue of Geophysical Research Letters, concludes the drought of 1934, during the Dust Bowl years in the North American Plains, was 30% more severe than the next worst, which occurred in 1580, NASA scientists said. The scientists used tree ring records from 1000 to 2005 along with modern observations. They found that the 1934 drought extended across over 71% of western North America, compared with almost 60% during the 2012 drought. “It was the worst by a large margin,” said lead author of the study Ben Cook [NASA’s Goddard Institute for Space Studies—Climate Scientist]. The scientists found two main reasons: a winter high-pressure system over the West Coast that blocked precipitation and spring dust storms that suppressed rainfall.

GRACE Spacecraft Changed the Way Groundwater was Measured; CBS’ 60 Minutes. Leslie Stahl hosted a segment on California’s groundwater issues. The segment described the difficulty in sampling groundwater levels until NASA’s Gravity Recovery and Climate Experiment (GRACE) spacecraft was launched. Mike Watkins [JPL—GRACE Project Scientist] described how GRACE “can tell whether an area has gained water weight or lost it.” Jay Famiglietti [University of California, Irvine] said that he thought the method was “complete nonsense” until he started examining the data, which changed his position. The broadcast noted that Famiglietti was so worried by what he saw in the data that he is working “to alert governments and academics to the problem.”

November Puzzler

November 25th, 2014 by Mike Carlowicz

puzzler-November-2014

Every month we offer a puzzling satellite image, and the November 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 five days 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!

Holuhruan: Still Erupting

November 14th, 2014 by Adam Voiland
holuhraun_oli_2014249

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

OctoberPuzzler_2014_annotated

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

OctoberPuzzler_2014

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

SeptPuzzler_2014

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!