Scientist to Gather Greenhouse Gas Emissions from Melting Permafrost

Goddard scientist Emily Wilson poses here with an early version or prototype of her recently miniaturized laser heterodyne radiometer — an instrument for which she received a patent in 2014. Image Credit: NASA

A NASA scientist who has developed a novel suitcase-size instrument to measure column carbon dioxide and methane is taking her recently patented instrument on the road this summer to comprehensively measure emissions of these important greenhouse gases from Alaska’s melting permafrost. 

Emily Wilson, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will use her recently patented miniaturized laser heterodyne radiometer (mini-LHR) to carry out a multi-disciplinary field campaign at three sites — each representing a different type of permafrost — near Fairbanks, Alaska, in June. Her team has designed a unique and comprehensive experiment that records permafrost depth and structure, meteorological data, and concentrations of methane and carbon dioxide during the seasonal ground melt.

Multi-Disciplinary Approach

“With the global mean temperature rising, the release of these gases could create an amplified effect,” she said. “These data will allow us to estimate fluctuation of emissions from the melting permafrost.”

Permafrost is permanently frozen soil. Comprising 24 percent of the Northern Hemisphere, permafrost contains old organic carbon deposits — some relicts from the last glaciation — that are locked up beneath the surface. Scientists have observed that more of the permafrost’s upper layer, or the active layer, is melting each summer, creating concern that the thawing could lead to the significant greenhouse-gas emissions.

Further exacerbating the situation is the fact that while methane doesn’t linger as long as carbon dioxide in the atmosphere, it is more potent and effective at absorbing heat, creating a positive feedback, where emissions leads to more warming, which in turn accelerates the thaw.

Highly portable, the mini-LDR is ideal for permafrost studies, Wilson said. Made up of commercially available components, the instrument literally can go anywhere to measure carbon dioxide and methane in the atmospheric column — that is, the levels of these gases in a vertical column extending from the ground to space. Currently, the only ground-based network that measures these two greenhouse gases in the atmospheric column is the Total Carbon Column Observing Network. However, the network has 22 operational sites globally, with limited coverage in the Arctic.

“We’re targeting areas where there is limited coverage,” she said.

To prepare for the campaign, Wilson made her instrument more rugged and more sensitive. She added a satellite communications port to remotely retrieve data, a thermally controlled instrument housing to protect the instrument from changing temperatures, and a solar grid and battery storage system for powering the instrument in remote locations.

Source: Nasa

The Cosmic radio burst caught red-handed

A schematic illustration of CSIRO’s Parkes radio telescope receiving the polarised signal from the new ‘fast radio burst’. Credit: Swinburne Astronomy Productions.

Pasadena, CA— Fast radio bursts are quick, bright flashes of radio waves from an unknown source in space. They are a mysterious phenomenon that last only a few milliseconds, and until now they have not been observed in real time. An international team of astronomers, including three from the Carnegie Observatories, has for the first time observed a fast radio burst happening live. Their work is published in Monthly Notices of the Royal Astronomical Society.

There is a great deal of scientific interest in fast radio bursts, particularly in uncovering their origin.

“These events are one of the biggest mysteries in the Universe” noted Carnegie Observatories' Acting Director John Mulchaey. “Until now, astronomers were not able to catch one of these events in the act.”

Only seven fast radio bursts have previously been discovered, since the first one found in 2007. All were found retroactively by combing through data from the Parkes radio telescope in eastern Australia and the Arecibo telescope in Puerto Rico.

“These bursts were generally discovered weeks or months or even more than a decade after they happened! We’re the first to catch one in real time,” said Emily Petroff, a PhD candidate from Swinburne University of Technology in Melbourne, Australia and lead author of the publication.
Swinburne is a member institution of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO).

In order to observe the fast radio burst in real time, the team mobilized 12 telescopes around the world and in space, including Carnegie’s Magellan and Swope telescopes. Each telescope followed-up on the original burst observation at different wavelengths.

Measurements of the interaction between previously detected fast radio burst’s flashes and the free electrons their signals encountered in space as they traveled to reach us had previously indicated that the bursts likely originated far outside of our galaxy. But the idea was controversial.

The team’s data indicates that the burst originated up to 5.5 billion light years away. This means that the sources of theses bursts are extremely bright and could perhaps be used as a cosmological tool for measuring and understanding our universe once we come to understand them better.

“Together, our observations allowed the team to rule out some of the previously proposed sources for the bursts, including nearby supernovae,” explained Carnegie’s Mansi Kasliwal who was on the team along with Mulchaey and colleague Yue Shen. “Short gamma-ray bursts are still a possibility, as are distant magnetic neutron stars called magnetars, but not long gamma ray bursts.”

Gamma ray bursts are high-energy explosions that form some of the brightest celestial events. Long bursts can signify energy released during a supernova and are followed by an afterglow, which emits lower wavelength radiation than the original explosion.

Another interesting piece of information the team was able to gather about the burst is its polarization. The orientation of the radio waves indicates that the burst likely originated near or passed through a magnetic field, information that can help narrow down potential sources going forward.

“As we continue to search for the source of fast radio bursts, Carnegie is well positioned to make big strides in the field,” Mulchaey said. “Quick access to big telescopes like Magellan may be the key to solving this mystery.”

Caption: A schematic illustration of CSIRO’s Parkes radio telescope receiving the polarised signal from the new fast radio burst. Image is credited to Swinburne Astronomy Productions.

Other co-authors are: M. Bailes (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics); E.D. Barr (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics); B. R. Barsdell (Harvard-Smithsonian Center for Astrophysics); N. D. R. Bhat (ARC Centre of Excellence for All-sky Astrophysics and Curtin University) ; F. Bian (Australian National University); S. Burke-Spolaor (Caltech); M. Caleb(Australian National University, Swinburne University of Technology, ARC Centre of Excellence for All-sky Astrophysics); D. Champion (Max Planck Institut für Radioastronomie); P. Chandra (Tata Institute of Fundamental Research Pune University Campus); G. Da Costa (Australian National University); C. Delvaux (Max-Planck-Institut für extraterrestrische Physik); C. Flynn (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics); N. Gehrels (NASA Goddard Space Flight Center); J. Greiner (Max-Planck-Institut für extraterrestrische Physik); A. Jameson (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics); S. Johnston (CSIRO Astronomy & Space Science Australia Telescope National Facility); E. F. Keane (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics); S. Keller (Australian National University); J. Kocz (Harvard-Smithsonian Center for Astrophysics and Jet Propulsion Laboratory, Caltech); M. Kramer (Max Planck Institut für Radioastronomie and University of Manchester) G. Leloudas (University of Copenhagen and Weizmann Institute of Science); D. Malesani (University of Copenhagen); C. Ng (Max Planck Institut für Radioastronomie); E. O. Ofek (Weizmann Institute of Science); D. A. Perley (Caltech); A. Possenti (Osservatorio Astronomico di Cagliari); B. P. Schmidt (Australian National University and ARC Centre of Excellence for All-sky Astrophysics); B. Stappers (University of Manchester); P. Tisserand (Australian National University and ARC Centre of Excellence for All-sky Astrophysics); W. van Straten (Swinburne University of Technology and ARC Centre of Excellence for All-sky Astrophysics ); and C. Wolf (Australian National University and ARC Centre of Excellence for All-sky Astrophysics).

The Parkes radio telescope and the Australia Telescope Compact Array are part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility and managed by CSIRO. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO). GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. Research with the ANU SkyMapper telescope is supported in part through an ARC Discovery Grant. Part of the funding for GROND was granted from a Leibniz-Prize. The Dark Cosmology Centre is supported by the Danish National Research council. Other support came from Curtin Research Fellowship;, EXTraS, funded from the European Union's Seventh Framework Programme for research, technological development and demonstration; Hubble Fellowships; a Carnegie-Princeton Fellowship; the Arye Dissentshik career development; the Willner Family Leadership Institute Ilan Gluzman (Secaucus, N.J.), the Israeli Ministry of Science; Israel Science Foundation; Minerv;, Weizmann-UK; the I-CORE Program of the Planning and Budgeting Committee.

The Carnegie Institution for Science (carnegiescience.edu) is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

watch video


Source: Royal Astronomical Society

Scientists twist radio beams to send data: Transmissions reach speeds of 32 gigibits per second

Graphic showing the intensity of the radio beams after twisting.
Credit: Courtesy of Alan Willner / USC Viterbi

Building on previous research that twisted light to send data at unheard-of speeds, scientists at USC have developed a similar technique with radiowaves, reaching high speeds without some of the hassles that can go with optical systems.

The researchers, led by electrical engineering professor Alan Willner of the USC Viterbi School of Engineering, reached data transmission rates of 32 gigabits per second across 2.5 meters of free space in a basement lab at USC.

For reference, 32 gigabits per second is fast enough to transmit more than 10 hour-and-a-half-long HD movies in one second and is 30 times faster than LTE wireless.

"Not only is this a way to transmit multiple spatially collocated radio data streams through a single aperture, it is also one of the fastest data transmission via radio waves that has been demonstrated," Willner said.

Faster data transmission rates have been achieved -- Willner himself led a team two years ago that twisted light beams to transmit data at a blistering 2.56 terabits per second -- but methods to do so rely on light to carry the data.

"The advantage of radio is that it uses wider, more robust beams. Wider beams are better able to cope with obstacles between the transmitter and the receiver, and radio is not as affected by atmospheric turbulence as optics," Willner said.

Willner is the corresponding author of an article about the research that will be published in Nature Communications on Sept. 16. The study's co-lead authors Yan Yan and Guodong Xie are both graduate students at USC Viterbi, and other contributors came from USC, the University of Glasgow, and Tel Aviv University.

To achieve the high transmission rates, the team took a page from Willner's previous work and twisted radio beams together. They passed each beam -- which carried its own independent stream of data -- through a "spiral phase plate" that twisted each radio beam into a unique and orthogonal DNA-like helical shape. A receiver at the other end of the room then untwisted and recovered the different data streams.

"This technology could have very important applications in ultra-high-speed links for the wireless 'backhaul' that connects base stations of next-generation cellular systems," said Andy Molisch of USC Viterbi. Molisch, whose research focuses on wireless systems, co-designed and co-supervised the study with Willner.

Future research will focus on attempting to extend the transmission's range and capabilities.

The work was supported by Intel Labs University Research Office and the DARPA InPho (Information in a Photon) Program.

Source: University of Southern California