PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

AGU journal highlights -- Oct. 5, 2010

2010-10-06
(Press-News.org) The following highlights summarize research papers that have been recently published in Geophysical Research Letters (GRL), Journal of Geophysical Research-Atmospheres (JGR-D), or Water Resources Research (WRR).

1. Antarctic sea ice increase not linked to ozone hole

While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simulations have indicated that the ozone hole induces a large change in atmospheric circulation in austral summer and that this change in circulation could contribute to the changing Antarctic sea extent.

To learn more, Sigmond and Fyfe use a climate model, forced by monthly varying observed stratospheric ozone changes from 1979 to 2005, to simulate the effects of stratospheric ozone depletion on Antarctic sea ice extent. Contrary to predictions of previous studies, their model finds that ozone depletion would lead to a year-round decrease in Antarctic sea ice extent rather than the increase that was observed. The results suggest that processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent. It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.

Title: Has the ozone hole contributed to increased Antarctic sea ice extent?

Authors: M. Sigmond: Department of Physics, University of Toronto, Toronto, Ontario, Canada;

J. C. Fyfe: Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada.

Source: Geophysical Research Letters, doi:10.1029/2010GL044301, 2010 http://dx.doi.org/10.1029/2010GL044301



2. Lunar topography gets closer look

Selection of landing sites for potential human or robotic lunar missions requires precise knowledge of lunar topography. Contributing to that knowledge, Smith et al. present initial observations from the Lunar Orbiter Laser Altimeter (LOLA) on board the Lunar Reconnaissance Orbiter. The LOLA measurements provide a high-resolution global model of lunar topography based on more observations and observations with greater accuracy than previous lunar topography maps. LOLA also collected high-resolution data on the slope, roughness, and reflectance of the lunar surface.

Title: Initial observations from the Lunar Orbiter Laser Altimeter (LOLA)

Authors: David E. Smith: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA and Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA;

Maria T. Zuber: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;

Gregory A. Neumann, Frank G. Lemoine, and Erwan Mazarico: Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA;



(For listing of all 20 authors, please see abstract at link below.)

Source: Geophysical Research Letters, doi:10.1029/2010GL043751, 2010 http://dx.doi.org/10.1029/2010GL043751

3. Earth's rotation affects flows in submarine channels

Coriolis forces due to the Earth's rotation deflect winds and ocean flows to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In sinuous submarine channels, Coriolis forces can drive secondary circulation of turbidity currents and determine where erosion and sediment deposition occur. Cossu and Wells conducted laboratory experiments with a channel in a rotating tank to study the conditions under which Coriolis forces dominate the channel flow and to investigate how these forces affect sediment deposition in large-scale submarine channels.

They find that channels at high latitudes and those with large bends are dominated by Coriolis forces, while channels at lower latitudes and those with smaller, tighter bends are less influenced by Coriolis forces. The researchers also show how Coriolis forces affect secondary circulation in successive bends of a sinuous channel. In Northern Hemisphere channels dominated by Coriolis forces, flow is directed toward the outer bank when the channel turns left and toward the inner bank when the channel turns right. In channels where the Coriolis force does not dominate, centrifugal forces direct flow toward the outer bank at all turns in the channel, regardless of the direction of the turn. These forces affect where sedimentation and erosion occur and contribute to the shape and levee asymmetry of the channel.

Title: Coriolis forces influence the secondary circulation of gravity currents flowing in large-scale sinuous submarine channel systems

Authors: Remo Cossu, Department of Geology, University of Toronto, Toronto, Ontario, Canada;

Mathew Wells, Department of Physical & Environmental Sciences, University of Toronto, Toronto, Ontario, Canada.

Source: Geophysical Research Letters, doi:10.1029/2010GL044296, 2010 http://dx.doi.org/10.1029/2010GL044296

4. No lightning detected on Mars during 5-year search

It has been suggested that dust storms on Mars might generate electric fields large enough to produce lightning-like electrical discharges, and a recent study reported evidence of such lightning. If lightning does occur on Mars, it could present a hazard for spacecraft or manned missions to the planet. However, Gurnett et al. report that a 5-year search using a radar receiver on board the Mars Express spacecraft finds no evidence of lightning at frequencies between 4.0 and 5.5 megahertz, although there were two major dust storms and many smaller storms during the time period. The search does not rule out the possibility of lightning on Mars at substantially higher or lower frequencies.

Title: Non-detection of impulsive radio signals from lightning in Martian dust storms using the radar receiver on the Mars Express spacecraft

Authors: D. A. Gurnett, D. D. Morgan, and L. J. Granroth: Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA;

B. A. Cantor: Malin Space Science Systems, Inc., San Diego, California, USA;

W. M. Farrell and J. R. Espley: NASA Goddard Spaceflight Center, Greenbelt, Maryland, USA.

Source: Geophysical Research Letters, doi:10.1029/2010GL044368, 2010 http://dx.doi.org/10.1029/2010GL044368

5. Teasing out aerosol influences on precipitation

Aerosol particles such as dust, smog, smoke, and oceanic haze play an important role in the physics of cloud generation—with all other factors fixed, an increase in aerosol concentrations results in more numerous but smaller water droplets within clouds. Further, high concentrations of aerosols make it harder for cloud droplets to coalesce into larger droplets, thus suppressing the ability of clouds to form rain. But the nature and magnitude of this effect are highly uncertain, making it difficult to model how increased pollution levels will affect rain patterns.

Sorooshian et al. suggest that determining how aerosols influence clouds becomes easier to quantify if observations are classified into two categories: how aerosols interact with clouds, and how clouds form precipitation. This split allows for each process to be weighed against other meteorological factors that could mask the response of clouds to aerosols. Through testing this method with data from satellites, aircraft, and other models, the authors find that splitting cloud behavior into different components helps increase the certainty with which scientists can say that specific perturbations in aerosol levels are linked to changes in precipitation.

Title: Deconstructing the precipitation susceptibility construct: Improving methodology for aerosol-cloud precipitation studies

Authors: Armin Sorooshian: Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA; also at Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona, USA;

Graham Feingold and Hongli Jiang: Earth Systems Research Laboratory, U.S. National Oceanic and Atmospheric Administration. Boulder, Colorado, USA;

Matthew D. Lebsock and Graeme L. Stephens: Department of Atmospheric Sciences, Colorado State University, Fort Collins, Colorado, USA.

Source: Journal of Geophysical Research-Atmospheres, doi:10.1029/2009JD013426, 2010 http://dx.doi.org/10.1029/2009JD013426

6. Magma chamber imaged under ancient Indonesian caldera

The Toba caldera in northern Sumatra, Indonesia, was formed about 75,000 years ago by an enormous explosive volcanic eruption that had significant effect on global climate. To learn more about its underlying crustal structure, Stankiewicz et al. create a three-dimensional image of the magma chamber underneath the lake using a technique called ambient noise tomography, which they apply to seismic noise data recorded by an array of 40 stations around Lake Toba between May and October 2008. In addition to demonstrating the use of this recently developed imaging method, the study confirms that the geometry of the magma chamber under the Toba caldera is complex, with at least two separate subchambers.

Title: Lake Toba volcano magma chamber imaged by ambient seismic noise tomography

Authors: Jacek Stankiewicz, Trond Ryberg, and Christian Haberland: Deutsches GeoForschungsZentrum GFZ, Telegrafenberg 14473 Potsdam, Section 2.2, Germany;

Fauzi: Meteorological, Climatological and Geophysical Agency (BMKG), Jakarta, Indonesia;

Danny Natawidjaja: Indonesian Institute of Sciences (LIPI), Bandung, Indonesia.

Source: Geophysical Research Letters, doi:10.1029/2010GL044211, 2010 http://dx.doi.org/10.1029/2010GL044211

7. Modeling ionospheric variations

Plasma density irregularities in the ionosphere are important to understand and predict because they can cause radio scintillation that affects communications and navigation systems. During an ionospheric phenomenon known as equatorial spread F, or ESF, large-scale electron density bubbles can be generated and rise to high altitudes. Researchers would like to understand the day-to-day variability of ESF, but these variations are driven by complex processes and can be difficult to model. Huba and Joyce create a three-dimensional global model of the onset and evolution of ESF. They show that ESF can be triggered by presunset ionospheric density perturbations and that an existing ESF plasma bubble can trigger a new bubble.

Title: Global modeling of equatorial plasma bubbles

Authors: J.D. Huba: Plasma Physics Division, Naval Research Laboratory, Washington, DC, USA;

G. Joyce: Icarus Research, Inc., Bethesda, MD, USA.

Source: Geophysical Research Letters, doi:10.1029/2010GL044281, 2010 http://dx.doi.org/10.1029/2010GL044281



8. A less invasive method to measure groundwater permeability

Hydraulic conductivity quantifies how easily water moves through aquifers, a factor important for management of water resources, the design of wells, and remediation of contaminated sites. It typically shows strong spatial fluctuations, so determining hydraulic conductivity usually involves extensive, invasive, and often expensive installation of wells or sampling sites within the aquifer.

Pollock and Cirpka have come up with an alternative method. They inject a salt solution into the subsurface, thus changing its electrical properties. The propagation of the solution through the aquifer can then be followed by electrical measurements scattered over the survey area. By innovatively coupling the system of groundwater flow, solute transport, and electrical currents, they can directly deduce the spatial distribution of hydraulic conductivity in the aquifer, and also resolve fine-scale features without major invasions into the subsurface.

Title: Fully coupled hydrogeophysical inversion of synthetic salt tracer experiments

Authors: Davina Pollock: Center for Applied Geoscience, University of Tübingen, Tübingen, Germany; also at Department of Environmental Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland;

Olaf A. Cirpka: Center for Applied Geoscience, University of Tübingen, Tübingen, Germany.

Source: Water Resources Research, doi:10.1029/2009WR008575, 2010 http://dx.doi.org/10.1029/2009WR008575

9. Ocean color affects tropical cyclone formation

The color of the ocean can alter the frequency of tropical cyclones, according to a recent study. The absorption of sunlight is affected by the concentration of chlorophyll, with the Sun's heat penetrating deeper in clear, low-chlorophyll waters. In ocean gyres, this heat can get carried away, so that lower concentrations of chlorophyll are associated with colder surface waters. Ocean surface temperatures can affect atmospheric circulation patterns, and thus the formation of cyclones and other weather patterns.

Gnanadesikan et al. use a coupled climate model to study how chlorophyll levels could affect tropical cyclones. They simulate the formation rate of cyclones in the subtropical North Pacific under scenarios with current chlorophyll levels, with half of current chlorophyll levels, and with no chlorophyll. They find that reducing chlorophyll focused the paths of cyclones along the equator. Eliminating all chlorophyll would reduce tropical cyclone activity poleward of 15 degrees North latitude by two thirds.

Although a no-chlorophyll scenario is extreme, the researchers note other research suggesting that 1960s chlorophyll levels in the Pacific were about 50 percent lower than at present. As tropical cyclone activity has increased since that time, they suggest that ocean color could be a factor that should be taken into account in explaining and predicting such changes.

See 13 August press release at: http://www.agu.org/news/press/pr_archives/2010/2010-25.shtml

Title: How ocean color can steer Pacific tropical cyclones

Authors: Anand Gnanadesikan: Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA;

Kerry Emanuel:Department of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;

Gabriel A. Vecchi, Whit G. Anderson, and Robert Hallberg: Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA.

Source: Geophysical Research Letters, doi:10.1029/2010GL044514, 2010 http://dx.doi.org/10.1029/2010GL044514



10. Simulations show deep oil from leak confined to Gulf of Mexico

The Deepwater Horizon oil leak was one of the largest environmental disasters in recent history, and aspects of its environmental impact are still unknown. In addition to surface oil slicks, large underwater plumes of oil were found. To help evaluate the potential environmental impact, Adcroft et al. ran simulations of underwater plumes of dissolved and suspended oil originating from a point source in the Gulf of Mexico. They assess dispersal and decay mechanisms, examining the possibility that toxic concentrations of dissolved oil might exit the Gulf of Mexico. They find that when ocean circulation and microbial oxidation rates are taken into account, toxic levels of dissolved oil were confined to the northern Gulf of Mexico, indicating that the environmental impact would be limited to that area.

See 19 August press release at: http://www.agu.org/news/press/pr_archives/2010/2010-26.shtml

Title: Simulations of underwater plumes of dissolved oil in the Gulf of Mexico

Authors: Alistair Adcroft: Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey, USA and Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA;

Robert Hallberg, John P. Dunne, and Bonita L. Samuels: Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA;

J. A. Galt, Christopher H. Barker, and Debra Payton: Office of Response and Restoration, NOAA, Seattle, Washington, USA.

Source: Geophysical Research Letters, doi:10.1029/2010GL044689, 2010 http://dx.doi.org/10.1029/2010GL044689

11. Limiting global warming might not limit heatwave risk

Recent policy discussions on climate change have focused on limiting global average temperature increases. For instance, the European Union has set a goal of limiting global warming to 2 degrees Celsius (3.6 degrees Fahrenheit). However, this goal represents a global average—regional and local temperature changes may vary, and substantial increases in regional extreme heat events could occur, possibly with serious consequences for some communities. To help inform discussion, Clark et al. used an ensemble of climate simulations to study the potential increase in extreme heat waves under a scenario in which global warming is limited. They found that even if average warming is limited to 2 degrees C, estimated increases in temperature during the hottest days range from 2 degrees C to 6 degrees C (11 degrees F) for parts of Europe, North America, and Asia. The researchers also investigate the sources of uncertainty in estimates of regional changes.

See 17 August post on AGU's Geospace blog at: http://blog.agu.org/geospace/2010/08/17/dangerous-heat-waves-to-worsen-even-with-strong-climate-action/

Title: Do global warming targets limit heatwave risk?

Authors: Robin T. Clark, James M. Murphy, Simon J. Brown: Met Office Hadley Centre, Exeter, UK.

Source: Geophysical Research Letters, doi:10.1029/2010GL043898, 2010 http://dx.doi.org/10.1029/2010GL043898

### Anyone may read the scientific abstract for any already-published paper by clicking on the link provided at the end of each Highlight. You can also read the abstract by going to http://www.agu.org/pubs/search_options.shtml and inserting into the search engine the full doi (digital object identifier), e.g. 10.1029/2010GL044301. The doi is found at the end of each Highlight above.

Journalists and public information officers (PIOs) at educational or scientific institutions, who are registered with AGU, also may download papers cited in this release by clicking on the links above. Instructions for members of the news media, PIOs, and the public for downloading or ordering the full text of any research paper summarized above are available at http://www.agu.org/news/press/papers.shtml.

END



ELSE PRESS RELEASES FROM THIS DATE:

Oldest evidence of dinosaurs found in Polish footprints

Oldest evidence of dinosaurs found in Polish footprints
2010-10-06
The oldest evidence of the dinosaur lineage—fossilized tracks—is described this week in Proceedings of the Royal Society B. Just one or two million years after the massive Permian-Triassic extinction, an animal smaller than a house cat walked across fine mud in what is now Poland. This fossilized trackway places the very closest relatives of dinosaurs on Earth about 250 million years ago—5 to 9 million years earlier than previously described fossilized skeletal material has indicated. The paper also described the 246-million-year-old Sphingopus footprints, the oldest evidence ...

Study: Small firms need more access to credit during financial troubles

Study: Small firms need more access to credit during financial troubles
2010-10-06
CHAMPAIGN, Ill. – When the economy sours, small firms seeking credit tend to face higher costs of financing, leading them to reinvest their profits before they pay off creditors, according to research published by a University of Illinois finance expert. Small firms, especially those considered financially constrained as a result of their size, low dividend payment or lack of bond rating, often become bogged down in debt because they "get hooked on cheap money, when they can find it" says U. of I. finance professor Murillo Campello. "Since small firms are usually financially ...

New fisheries system will save about $20 million, Iowa State University researchers find

New fisheries system will save about $20 million, Iowa State University researchers find
2010-10-06
AMES, Iowa - Some fisheries in the United States are poised to undergo major changes in the regulations used to protect fish stocks, and Iowa State University researchers have estimated that the new system will be an economic boon to the fishing industry. Quinn Weninger and Rajesh Singh, both associate professors in economics, estimated harvesting costs under the old system and compared that to the newly proposed fishing regulations that lift many restrictions that cause inefficiency while still limiting amounts to be harvested. Their analysis focused on the Pacific Groundfish ...

Animations show extent of marcellus shale development

2010-10-06
The pace and extent of Marcellus Shale development across Pennsylvania can be "seen" in animated maps produced by the Penn State Marcellus Center for Outreach and Research. Based on data from the Pennsylvania Department of Environmental Protection, the animations (http://www.marcellus.psu.edu/resources/maps.php) show both the number of drilling permits issued for the Marcellus Shale target and the number of wells drilled by year from 2007 through August 2010. Although permits were issued prior to 2007, information on those permits did not include latitude and longitude. "These ...

A thirst for excitement is hidden in your genes

2010-10-06
Sensation seeking—the urge to do exciting things—has been linked to dopamine, a chemical that carries messages in your brain. For a new study published in Psychological Science, a journal of the Association for Psychological Science, scientists analyzed genes in the dopamine system and found a group of mutations that help predict whether someone is inclined toward sensation seeking. Sensation seeking has been linked to a range of behavior disorders, such as drug addiction. It isn't all bad, though. "Not everyone who's high on sensation seeking becomes a drug addict. They ...

UNH researcher helps identify key reproductive hormone in oldest vertebrate

2010-10-06
DURHAM, N.H. -- Looking at a hagfish – an eyeless, snot-covered, worm-like scavenger of the deep –the last thing that comes to mind is sex. Yet the reproductive functioning of these ancient vertebrates is such an enduring enigma that a gold medal was once offered to anyone who could elucidate it. Although the prize expired, unclaimed, long ago, University of New Hampshire professor of biochemistry Stacia Sower and colleagues at two Japanese universities have identified the first reproductive hormone of the hagfish – a gonadatropin -- representing a significant step toward ...

Early lung cancer detection

2010-10-06
Researchers from Northwestern University and NorthShore University HealthSystem (NorthShore) have developed a method to detect early signs of lung cancer by examining cheek cells in humans using pioneering biophotonics technology. "By examining the lining of the cheek with this optical technology, we have the potential to prescreen patients at high risk for lung cancer, such as those who smoke, and identify the individuals who would likely benefit from more invasive and expensive tests versus those who don't need additional tests," said Hemant K. Roy, M.D., director ...

Air pollution alters immune function, worsens asthma symptoms

2010-10-06
Berkeley – Exposure to dirty air is linked to decreased function of a gene that appears to increase the severity of asthma in children, according to a joint study by researchers at Stanford University and the University of California, Berkeley. While air pollution is known to be a source of immediate inflammation, this new study provides one of the first pieces of direct evidence that explains how some ambient air pollutants could have long-term effects. The findings, published in the October 2010 issue of the Journal of Allergy and Clinical Immunology, come from ...

Doppler radars help increase monsoon rainfall prediction accuracy

2010-10-06
WEST LAFAYETTE, Ind. - Doppler weather radar will significantly improve forecasting models used to track monsoon systems influencing the monsoon in and around India, according to a research collaboration including Purdue University, the National Center for Atmospheric Research and the Indian Institute of Technology Delhi. Dev Niyogi, a Purdue associate professor of agronomy and earth and atmospheric sciences, said modeling of a monsoon depression track can have a margin of error of about 200 kilometers for landfall, which can be significant for storms that produce as ...

GOES-13 sees another potential tropical depression in Caribbean Sea

GOES-13 sees another potential tropical depression in Caribbean Sea
2010-10-06
The GOES-13 satellite passed over a low pressure area designated as "System 97L" earlier today and captured a visible image of the low in the eastern Caribbean Sea. System 97L appears in a good place for development into a tropical depression in the next day or two. The National Hurricane Center currently gives the low pressure area known as System 97L an "80 percent chance of developing into a tropical depression in the next 48 hours." The low pressure area is located just north of the Virgin Islands near 19.0 North latitude and 65.3 West longitude. The visible image ...

LAST 30 PRESS RELEASES:

UT Health San Antonio ranks at the top 5% globally among universities for clinical medicine research

Fayetteville police positive about partnership with social workers

Optical biosensor rapidly detects monkeypox virus

New drug targets for Alzheimer’s identified from cerebrospinal fluid

Neuro-oncology experts reveal how to use AI to improve brain cancer diagnosis, monitoring, treatment

Argonne to explore novel ways to fight cancer and transform vaccine discovery with over $21 million from ARPA-H

Firefighters exposed to chemicals linked with breast cancer

Addressing the rural mental health crisis via telehealth

Standardized autism screening during pediatric well visits identified more, younger children with high likelihood for autism diagnosis

Researchers shed light on skin tone bias in breast cancer imaging

Study finds humidity diminishes daytime cooling gains in urban green spaces

Tennessee RiverLine secures $500,000 Appalachian Regional Commission Grant for river experience planning and design standards

AI tool ‘sees’ cancer gene signatures in biopsy images

Answer ALS releases world's largest ALS patient-based iPSC and bio data repository

2024 Joseph A. Johnson Award Goes to Johns Hopkins University Assistant Professor Danielle Speller

Slow editing of protein blueprints leads to cell death

Industrial air pollution triggers ice formation in clouds, reducing cloud cover and boosting snowfall

Emerging alternatives to reduce animal testing show promise

Presenting Evo – a model for decoding and designing genetic sequences

Global plastic waste set to double by 2050, but new study offers blueprint for significant reductions

Industrial snow: Factories trigger local snowfall by freezing clouds

Backyard birds learn from their new neighbors when moving house

New study in Science finds that just four global policies could eliminate more than 90% of plastic waste and 30% of linked carbon emissions by 2050

Breakthrough in capturing 'hot' CO2 from industrial exhaust

New discovery enables gene therapy for muscular dystrophies, other disorders

Anti-anxiety and hallucination-like effects of psychedelics mediated by distinct neural circuits

How do microbiomes influence the study of life?

Plant roots change their growth pattern during ‘puberty’

Study outlines key role of national and EU policy to control emissions from German hydrogen economy

Beloved Disney classics convey an idealized image of fatherhood

[Press-News.org] AGU journal highlights -- Oct. 5, 2010