Archive for July, 2016

If you are like me, you have probably fantasized about looking down and photographing Earth while floating in the zero gravity of space.

I suppose I should never say never, but my chances of becoming an astronaut do look pretty slim at this point in my life. But even if I can’t experience space firsthand, I may have have found the next best thing: merged panorama photographs that make me feel like I am up there. NASA astronaut Jeff Williams has been posting short video clips on his social media feeds and the results are stunning.

All of these panoramas were taken while he was orbiting about 250 miles (400 kilometers) above the surface of Earth on the International Space Station. At the time, he was moving about 17,150 miles (27,600 kilometers) per hour. The photos were taken from the Cupola, a dome-shaped module on the Space Station with bay windows that offer panoramic views of Earth. To make the videos, Williams (with help from NASA colleagues on the ground) stitched together several images into mosaics and then used computer software to pan across the mosaic.

I have posted a few of my favorites here: a sunset, the coastline of western Australia, the Andes Mountains, and Cuba’s Gulf of Batabano. Scroll down past the video for a view of one of the raw mosaics and some video of Williams explaining what it is like to take photographs from space. Browse more astronaut photography here and find more of Williams’ photography on Facebook, Twitter, and Instagram. In related stories from the Earth Observatory, learn more about sunsets seen from space, the Andes, and coastal Australia.

Here is how the raw mosaic of the Gulf of Batabano looked.

And here is Williams explaining the cameras he uses and how he makes the merged panoramas.

Research Roundup: The Latest on Methane

July 11th, 2016 by Adam Voiland

Global atmospheric concentrations of methane are rising—along with scientific scrutiny of this potent greenhouse gas. In March 2016, we published a feature story that took a broad look at why methane matters. Since that story came out, several new studies have been published. But first, some broader context from that feature story…

The long-term, global trend for atmospheric methane is clear. The concentration of the gas was relatively stable for hundreds of thousands of years, but then started to increase rapidly around 1750. The reason is simple: increasing human populations since the Industrial Revolution have meant more agriculture, more waste, and more fossil fuel production. Over the same period, emissions from natural sources have stayed about the same.

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The Zeppelin Observatory in Svalbard monitors methane concentrations. It is one of several stations that helps scientists assemble a global picture of atmospheric aerosols and pollutants. Photo courtesy of AGAGE.

If you focus on just the past five decades—when modern scientific tools have been available to detect atmospheric methane—there have been fluctuations in methane levels that are harder to explain. Since 2005, methane has been on the rise, and no one is quite sure why. Some scientists think tropical wetlands have gotten a bit wetter and are releasing more gas. Others point to the natural gas fracking boom in North America and its sometimes leaky infrastructure. Others wonder if changes in agriculture may be playing a role.

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A combination of historical ice core data and air monitoring instruments reveals a consistent trend: global atmospheric methane concentrations have risen sharply in the past 2000 years. (NASA Earth Observatory image by Joshua Stevens, using data from the EPA.)

The stakes are high when it comes to sorting out what is going on with methane. Global temperatures in 2014 and 2015 were warmer than at any other time in the modern temperature record, which dates back to 1880. The most recent decade was the warmest on the record.  The current year, 2016, is already on track to be the warmest. And carbon emissions — including methane — are central to that rise.

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Atmospheric methane has continued to increase, though the rate of the increase has varied considerably over time and puzzled experts. (NASA Earth Observatory image by Joshua Stevens, using data from NOAA.)

 

Isotope Data Suggests Fossil Fuels Not to Blame for Increase
Methane bubbles up from swamps and rivers, belches from volcanoes, rises from wildfires, and seeps from the guts of cows and termites (where is it made by microbes). Human settlements are awash with the gas. Methane leaks silently from natural gas and oil wells and pipelines, as well as coal mines. It stews in landfills, sewage treatment plants, and rice paddies. With so many different sources, many scientists who study methane are hesitant to pin the rising concentration of the gas on a particular source until more data is collected and analyzed.

However, an April 2016 study led by a researcher from New Zealand’s National Institute of Water and Atmospheric Research came down squarely on one side. After measuring the isotopic composition, or chemical structure, of carbon trapped in ice cores and archived air samples from a global network of monitoring stations, the scientists concluded that blaming the rise in atmospheric methane on fossil fuel production makes little sense.

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Chart from Schaefer et al.

 

When methane has extra neutrons in its chemical structure, it is said to be a “heavier” isotope; fewer neutrons make for “lighter” methane. Different processes produce different proportions of heavy and light methane. Lighter isotopes of a carbon (meaning they have a lower ratio of Carbon 13 to Carbon 12 than the atmosphere), for instance, are usually associated with methane recovered from fossil fuels.

As shown in the chart above, the authors observed a decrease in the isotopes associated with fossil fuels at all latitudes beginning in 2006. But at the same time, global concentrations of methane (blue line in the top chart) have risen. “The finding is unexpected, given the recent boom in unconventional gas production and reported resurgence in coal mining and the Asian economy. Either food production or climate-sensitive natural emissions are the most probable causes of the current methane increase,” the authors noted.

If fossil fuel production is not responsible for increasing concentrations of atmospheric methane, than what is? The authors say that more research is needed to be certain, but that there are indications that the agricultural sector in southeast Asia (especially rice cultivation and livestock production) is likely responsible.

Large Increase in U.S. Emissions over Past Decade
A March 2016 study led by Harvard researchers based on surface measurements and satellite observations  detected a 30 percent increase in methane emissions from the United States between 2002 and 2014 — an amount the authors argue could account for between 30 to 60 percent of the global growth in atmospheric methane during the past decade.

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Chart from Turner et al.

The most significant increase (in red, as observed with Japan’s Greenhouse Gases Observing Satellite) occurred in the central United States. However, the authors avoid making claims about why. “The U.S. has seen a 20 percent increase in oil and gas production and a nine-fold increase in shale gas production from 2002 to 2014, but the spatial pattern of the methane increase seen by GOSAT does not clearly point to these sources. More work is needed to attribute the observed increase to specific sources.”

First Time Satellite View of Methane Leaking from a Single Facility
For the first time, an instrument on a spacecraft has measured the methane emissions leaking from a single facility on Earth’s surface. The observation, detailed in a June 2016 study, was made by the hyperspectral spectrometer Hyperion on NASA’s Earth Observing-1 (EO-1) satellite. On three separate overpasses, Hyperion detected methane leaking from the Aliso Canyon gas leak, the largest methane leak in U.S. history.

“The percentage of atmospheric methane produced through human activities remains poorly understood. Future satellite instruments with much greater sensitivity can help resolve this question by surveying the biggest sources around the world and helping us to better understand and address this unknown factor in greenhouse gas emissions,” David Thompson, an atmospheric chemist at NASA’s Jet Propulsion Laboratory and an author of the study. For instance, the upcoming Environmental Mapping and Analysis Program (EnMAP) is a satellite mission (managed by the German Aerospace Center) that will provide new hyperspectral data for scientists for monitoring methane.

As detailed in a July 2016 study, scientists and engineering are also working on a project called GEO-CAPE that will result in the deployment of a new generation of methane-monitoring instruments on geostationary satellites that can monitor methane sources in North and South America on a more continuous basis. Current methane sensors operate in low-Earth orbit, and thus take several days or even weeks before they can observe the same methane hot spot. For instance, EO-1 detected the Aliso Canyon plume just three times between December 29, 2015 and February 14, 2016, due to challenges posed by cloud cover and the lighting angle. A geostationary satellite would have detected it on a much more regular basis.

July Puzzler

July 5th, 2016 by Adam Voiland

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Every month on Earth Matters, we offer a puzzling satellite image. The July 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 a blog post, 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!

Update: The answer is posted here.

May Puzzler Answer: Camp Springs Wind Farm

July 1st, 2016 by Adam Voiland

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Congratulations to Dan Mahr for being the first to solve our May puzzler. As Dan pointed out: “These are wind turbines, probably viewed from Landsat 8 OLI. The shadows of some turbines are visible from the diagonal roads connecting them.” Indeed, the Operational Land Imager on Landsat 8 captured this image of the Camp Springs Wind Farm in Scurry County, Texas, on April 29, 2015. You can learn more about these wind farms and surrounding landscape in our May 28, 2016, Image of the Day.

If you are interested in learning more about America’s wind infrastructure, check out WindFarm, an online database and interactive mapping tool from the U. S. Geological Survey. The database includes the location and other details about more than 47,000 wind turbines. Just choose one of the turbines and WindFarm will serve up key details (capacity, blade length, height, etc.) about it. The image below is a screenshot from WindFarm showing turbines that are part of the Camp Springs project in blue.

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To get a quick sense of where wind turbines in the United States are located, see the screenshot below. Turbines are shown with colored circles. The highest capacity turbines are red and yellow; lower capacity turbines are green and blue. Note the lack of turbines in the Southeast—a region known for having relatively weak winds. While development has lagged there as a result, the advent of a new generation of wind turbine with taller towers and more efficient blades is poised to change this.

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The U.S. Geological Survey developed the map by tapping publicly available data from the Federal Aviation Administration Digital Obstacle File and the using high-resolution aerial imagery to verify the locations of wind turbines. For more detailed description of the data used, see this report. For a more detailed overview of WindFarm, see this story and view this video.

Programming Note: The puzzler was on summer vacation in June, but it will return in July.