August 13, 2009, 7:03 AM CT

Hurricane seasons are more active

For a number of Americans who live on the Atlantic coast, Andrew, Ivan and Katrina are more than just names--they are reminders of the devastating impact of cyclonic activity in the region during hurricane season. If it seems like hurricane seasons have been more active in recent years, you're on to something. As per a paper reported in the August 13 issue of Nature, the frequency and strength of these powerful storms has grown in recent decades.

"We are at levels now that are about as high as anything we have seen in the past 1,000 years," said Michael Mann, director of the Earth System Science Center at Pennsylvania State University and the main author of the paper. Mann and his collaborators, Jeffrey P. Donnelly of the Woods Hole Oceanographic Institution, Jonathan D. Woodruff of the University of Massachusetts and Zhihua Zhang of Pennsylvania State University examined sediment samples from across the North Atlantic coast and statistical models of historic hurricane activities.

Their analysis allowed them to measure the severity of hurricane seasons over the past 1,500 years. The sediment samples match up relatively well with the computer models, both of which show a period of high activity around 1,000 AD, followed by a lull in activity. This medieval peak rivals and possibly exceeds the level of activity seen in recent decades......... Posted by: Tyler      Read more         Source

August 4, 2009, 8:20 AM CT

Technology to support deepwater crustal drilling

The Integrated Ocean Drilling Program (IODP), in collaboration with industry partner AGR Drilling Services, has engineered an ultra-deepwater drilling technology for use by IODP drilling vessels in scientific research. Originally developed for shallow-water oil and gas exploration, the "riserless mud recovery" technology (RMR) holds great promise for researchers striving to reach the long-held goal of Project Mohole in the 1950s: drilling all the way through ocean crust into the Earth's mantle; a frontier still not explored today. Drilled cores from the mantle could provide researchers with answers to questions about the structure, composition, mineralogy, and in situ physical properties of oceanic crust and the geological nature of the seismic Moho.

"With AGR Drilling Services' support," says Engineering Manager Greg Myers, "IODP led an engineering effort to adapt existing technology to drill very deep holes in very deep regions of the ocean. Up to now," he adds, "riserless mud recovery drilling was limited to shallower water depths. This ultra-deepwater drilling technology allows researchers to investigate subseafloor areas in great depths, where oceanic crust appears to be thinnersuch as in waters off Hawaii." As per Myers, an ultra-deepwater RMR system could be implemented as early as July 2011......... Posted by: Tyler      Read more         Source

July 31, 2009, 0:15 AM CT

Scientists refine, redefine seawater equation

This summer, one of the world's leading ocean science bodies, the United Nations Educational, Scientific and Cultural Organization's (UNESCO's) and Intergovernmental Oceanographic Commission (IOC) adopted the new international thermodynamic equation of state for seawater called TEOS-10. A complex, dynamic mixture of dissolved minerals, salts, and organic material, seawater has historically presented difficulties in terms of determining its physical chemical properties.

For 30 years, climate models have relied on a series of equations called the International Equation of State of Seawater or EOS-80, which uses the Practical Salinity Scale of seawater. This equation was used to determine the pressure, volume, temperature proprieties of seawater. Other thermodynamic properties, including heat capacity, enthalpy and sound speed were obtained using separate equations.

The Scientific Committee on Oceanic Research (SCOR) established a working group to look at the thermodynamic properties of seawater in 2005. The team included researchers from the Leibniz-Institut fr Ostseeforschung in Warnemnde (Gera number of), University of Miami (USA), Desert Research Institute - Nevada System of Higher Education (USA), Bedford Institute of Oceanography (Canada), the Commonwealth Scientific and Research Organization (Australia), the National Oceanographic Centre (United Kingdom) and the Institute of Marine Geology and Chemistry (China)......... Posted by: Tyler      Read more         Source

July 28, 2009, 11:20 PM CT

Wildfires to increase as climate warms

As the climate warms in the coming decades, atmospheric researchers at Harvard's School of Engineering and Applied Sciences (SEAS) and their colleagues expect that the frequency of wildfires will increase in a number of regions. The spike in the number of fires could also adversely affect air quality due to the greater presence of smoke.

The study, led by SEAS Senior Research Fellow Jennifer Logan, was reported in the June 18th issue of Journal of Geophysical Research In their pioneering work, Logan and her collaborators investigated the consequences of climate change on future forest fires and on air quality in the western United States. Prior studies have probed the links between climate change and fire severity in the West and elsewhere. The Harvard study represents the first attempt to quantify the impact of future wildfires on the air we breathe.

"Warmer temperatures can dry out underbrush, leading to a more serious conflagration once a fire is started by lightening or human activity," says Logan. "Because smoke and other particles from fires adversely affect air quality, an increase in wildfires could have large impacts on human health".

Using a series of models, the researchers predict that the geographic area typically burned by wildfires in the western United States could increase by about 50% by the 2050s due mainly to rising temperatures. The greatest increases in area burned (75-175%) would occur in the forests of the Pacific Northwest and the Rocky Mountains. In addition, because of extra burning throughout the western U.S., one important type of smoke particle, organic carbon aerosols, would increase, on average, by about 40 percent during the roughly half-century period......... Posted by: Tyler      Read more         Source

July 26, 2009, 12:43 AM CT

Improved air quality during Beijing Olympics

The air in Beijing during the 2008 Olympics was cleaner than the prior year's, due to aggressive efforts by the Chinese government to curtail traffic, increase emissions standards and halt construction in preparation for the games, as per a Cornell study.

Led by Max Zhang, assistant professor of mechanical and aerospace engineering, the study indicates that such measures as regulating traffic density and encouraging public transportation can have a significant impact on local air quality.

"We hope our study can help or advise local regulators and policymakers to adopt long-term sustainable emission controls to improve air quality," Zhang said. "That's our mission".

Published online July 11 in the journal Atmospheric Environment, the study was based on air quality readings before, during and after the Olympics. Leading up to the Olympics, the Chinese government barred more than 300,000 heavy-emission vehicles -- mostly trucks -- from the roads. The city also implemented rules in which only some people were allowed to drive on certain days based on their license plate numbers. As a result, close to 2 million vehicles were pulled from the roads. Other mandates involved halting construction and decreasing the use of coal in favor of natural gas for electricity......... Posted by: Tyler      Read more         Source

July 26, 2009, 12:32 AM CT

Hydrocarbons in the deep Earth?

The oil and gas that fuels our homes and cars started out as living organisms that died, were compressed, and heated under heavy layers of sediments in the Earth's crust. Researchers have debated for years whether some of these hydrocarbons could also have been created deeper in the Earth and formed without organic matter. Now for the first time, researchers have observed that ethane and heavier hydrocarbons can be synthesized under the pressure-temperature conditions of the upper mantle the layer of Earth under the crust and on top of the core. The research was conducted by researchers at the Carnegie Institution's Geophysical Laboratory, with colleagues from Russia and Sweden, and is reported in the July 26, advanced on-line issue of Nature Geoscience

Methane (CH₄) is the main constituent of natural gas, while ethane (C₂H₆) is used as a petrochemical feedstock. Both of these hydrocarbons, and others linked to fuel, are called saturated hydrocarbons because they have simple, single bonds and are saturated with hydrogen. Using a diamond anvil cell and a laser heat source, the researchers first subjected methane to pressures exceeding 20 thousand times the atmospheric pressure at sea level and temperatures ranging from 1,300 F to over 2,240 F. These conditions mimic those found 40 to 95 miles deep inside the Earth. The methane reacted and formed ethane, propane, butane, molecular hydrogen, and graphite. The researchers then subjected ethane to the same conditions and it produced methane. The transformations suggest heavier hydrocarbons could exist deep down. The reversibility implies that the synthesis of saturated hydrocarbons is thermodynamically controlled and does not require organic matter......... Posted by: Tyler      Read more         Source

July 21, 2009, 11:23 PM CT

Tiny diamonds on Santa Rosa Island

Nanosized diamonds found just a few meters below the surface of Santa Rosa Island off the coast of Santa Barbara provide good evidence of a cosmic impact event in North America approximately 12,900 years ago, as per a newly released study by scientists. Their hypothesis holds that fragments of a comet struck across North America at that time.

The research, published this week in the Proceedings of the National Academy of Sciences (PNAS), was led by James Kennett, professor emeritus at UC Santa Barbara, and Douglas J. Kennett, first author, of the University of Oregon. The two are a father-son team. They were joined by 15 other researchers.

"The pygmy mammoth, the tiny island version of the North American mammoth, died off at this time," said James Kennett. "Since it coincides with this event, we suggest it is related." He explained that this site, with its layer containing hexagonal diamonds, is also linked to other types of diamonds and with dramatic environmental changes and wildfires. They are part of a sedimentary layer known as the Younger Dryas Boundary.

"There was a major event 12,900 years ago," said James Kennett. "It is hard to explain this assemblage of materials without a cosmic impact event and associated extensive wildfires. This hypothesis fits with the abrupt climatic cooling as recorded in ocean-drilled sediments beneath the Santa Barbara Channel. The cooling resulted when dust from the high-pressure, high-temperature, multiple impacts was lofted into the atmosphere, causing a dramatic drop in solar radiation"......... Posted by: Tyler      Read more         Source

July 21, 2009, 10:30 PM CT

Mother's exposure to urban air pollutants

A mother's exposure to urban air pollutants known as polycyclic aromatic hydrocarbons (PAHs) can adversely affect a child's intelligence quotient or IQ, a study reports. PAHs are chemicals released into the air from the burning of coal, diesel, oil and gas, or other organic substances such as tobacco. In urban areas motor vehicles are a major source of PAHs.

The study, funded by the National Institute of Environmental Health Sciences (NIEHS), a component of the National Institutes of Health, the U.S. Environmental Protection Agency and several private foundations, observed that children exposed to high levels of PAHs in New York City had full scale and verbal IQ scores that were 4.31 and 4.67 points lower than those of less exposed children. High PAH levels were defined as above the median of 2.26 nanograms per cubic meter (ng/m3). A difference of four points, which was the average seen in this study, could be educationally meaningful in terms of school success, as reflected, for example, in standardized testing and other measures of academic performance. However, the scientists point out that the effects may vary among individual children.

"This research clearly shows that environmental PAHs at levels encountered in an urban setting can adversely affect a child's IQ," said Linda Birnbaum, Ph.D., director of NIEHS. "This is the first study to report an association between PAH exposure and IQ, and it should serve as a warning bell to us all. We need to do more to prevent environmental exposures from harming our children"......... Posted by: Tyler      Read more         Source

July 17, 2009, 0:01 AM CT

Solar cycle linked to global climate

Establishing a key link between the solar cycle and global climate, research led by researchers at the National Science Foundation (NSF)-funded National Center for Atmospheric Research (NCAR) in Boulder, Colo., shows that maximum solar activity and its aftermath have impacts on Earth that resemble La Nia and El Nio events in the tropical Pacific Ocean.

The research may pave the way toward predictions of temperature and precipitation patterns at certain times during the approximately 11-year solar cycle.

"These results are striking in that they point to a scientifically feasible series of events that link the 11-year solar cycle with ENSO, the tropical Pacific phenomenon that so strongly influences climate variability around the world," says Jay Fein, program director in NSF's Division of Atmospheric Sciences. "The next step is to confirm or dispute these intriguing model results with observational data analyses and targeted new observations".

The total energy reaching Earth from the sun varies by only 0.1 percent across the solar cycle. Researchers have sought for decades to link these ups and downs to natural weather and climate variations and distinguish their subtle effects from the larger pattern of human-caused global warming.

Building on prior work, the NCAR scientists used computer models of global climate and more than a century of ocean temperature to answer longstanding questions about the correlation between solar activity and global climate......... Posted by: Tyler      Read more         Source

July 16, 2009, 11:52 PM CT

Ancient global warming episode holds clues to future climate

When researchers take Earth's temperature, they commonly use thermometers. But when researchers want to figure out Earth's temperature in the past, they have to rely on other tools. One of these is deep-sea sediment cores (see Figure). Deep-sea sediments contain fossil remains of tiny marine creatures and other materials that sink to the ocean floor. Over millions of years, these materials pile up and build climate archives that tell stories about Earth's history. Today, researchers recover those archives during ocean drilling expeditions aboard research vessels such as the JOIDES Resolution (see Figure).

Now a team of scientists, led by Richard Zeebe of the University of Hawai'i at Manoa's School of Ocean and Earth Science and Technology, has examined data from sediment cores from around the world to study an ancient global warming episode, known as the Paleocene-Eocene Thermal Maximum. This warming event occurred about 55 million years ago and provides important clues about what the future may hold. By studying the past, the scientists contribute to better forecasting the future a principle once expressed by the English historian Edward Gibbon: "I know no way of judging of the future but by the past".

There is little doubt among researchers that the Earth is warming because of carbon dioxide emissions from human activities. But exactly how much the Earth will warm say until the end of the 21st century is still uncertain. In their study reported in the journal Nature Geoscience, Zeebe and his team help to resolve the question by studying a possible analog in the past. Using sediment archives and theoretical tools, they provide estimates of the amount of carbon dioxide in the atmosphere during the warming episode 55 million years ago......... Posted by: Tyler      Read more         Source