April 28, 2008, 8:27 PM CT

Satellite Mission To Map Earth's Water Cycle

MIT Professor Dara Entekhabi will lead the science team designing a NASA satellite mission to make global soil moisture and freeze/thaw measurements, data essential to the accuracy of weather forecasts and predictions of global carbon cycle and climate. NASA announced recently that the Soil Moisture Active-Passive mission (SMAP) is scheduled to launch December 2012.

At present, researchers have no network for gathering soil moisture data as they do for rainfall, winds, humidity and temperature. Instead, that data is gathered only at a few scattered points around the world.

"Soil moisture is the lynchpin of the water, energy and carbon cycles over land. It is the variable that links these three cycles through its control on evaporation and plant transpiration. Global monitoring of this variable will allow a new perspective on how these three cycles work and vary together in the Earth system," said Entekhabi, director of the Parsons Laboratory for Environmental Science and Engineering in MIT's Department of Civil and Environmental Engineering.

"Additionally because soil moisture is a state variable that controls both water and energy fluxes at the land surface, we anticipate that assimilation of the global observations will improve the skill in numerical weather prediction, particularly for events that are influenced by these fluxes at the base of the atmosphere," he said......... Posted by: Brooke      Read more         Source

April 28, 2008, 4:54 PM CT

'New' ancient Antarctic sediment reveals climate change history

Recent additions to the premier collection of Southern Ocean sediment cores at Florida State Universitys Antarctic Marine Geology Research Facility will give international researchers a close-up look at fluctuations that occurred in Antarcticas ice sheet and marine and terrestrial life as the climate cooled considerably between 20 and 14 million years ago.

FSUs latest Antarctic sediment core acquisition was extracted from deep beneath the sea floor of Antarcticas western Ross Sea, the Earths largest floating ice body. The new samples -- segments of a drill core that measures more than 1,100 meters in length -- offer an extraordinary stratigraphic record of sedimentary rock from the Antarctic continental margin that documents key developments in the areas Cenozoic climatic and glacial history.

By correlating that stratigraphic record with existing data and climate and ice sheet models, researchers from FSU and around the world expect to learn how local changes in the Southern Ocean region relate to regional and global climate events.

Such knowledge will significantly increase our understanding of Antarcticas potential responses to future global-scale climate changes, said Sherwood W. Wise, Jr., an FSU geological science professor and co-principal investigator at the Antarctic Marine Geology Research Facility. This is critical for low-lying regions such as Florida that could be directly affected by the future behavior of the Antarctic Ice Sheets and any resulting sea-level changes. By studying these glacial records of the past, geologists and climatologists seek to better predict the future......... Posted by: Tyler      Read more         Source

April 24, 2008, 10:28 PM CT

Biodiversity Is Crucial to Ecosystem Productivity

In the first experiment involving a natural environment, researchers at Brown University have shown that richer plant diversity significantly enhances an ecosystem's productivity. The finding underscores the benefits of biodiversity, such as capturing carbon dioxide, a main contributor to global warming.

Osvaldo Sala, director of the Environmental Change Initiative and the Sloan Lindeman Professor of Biology at Brown, and Pedro Flombaum, a postdoctoral research associate in the Department of Ecology and Evolutionary Biology at Brown, said the results confirmed tests charting how biodiversity affects aboveground plant productivity in artificial ecosystems. Aboveground plant productivity (ANPP) is the amount of biomass, or organic material, produced by plant growth.

But the Brown team also learned that the connection between plant species richness - the number of plant species in a unit of area - and ANPP in a natural ecosystem was greater than had been expected. What that means, the scientists wrote in a paper published online this week in the Proceedings of the National Academy of Sciences, is that the greater the number of plant species, the more productive the ecosystem.

On the other hand, species loss has a decidedly negative impact on ecosystems. This is particularly true in light of the role ecosystems play in capturing the global warming gas carbon dioxide: The fewer the plant species in a given natural environment, the less carbon dioxide they capture......... Posted by: Tyler      Read more         Source

April 24, 2008, 9:37 PM CT

Geological faults threaten Houston

HOUSTON, April 24, 2008 After finding more than 300 surface faults in Harris County, a University of Houston geologist now has information that could be vitally useful to the regions builders and city planners.

This information the most accurate and comprehensive of its kind was discovered by Shuhab Khan, assistant professor of geology, and Richard Engelkemeir, a geology Ph.D. student, using advanced radar-like laser technology. Eventhough geologists have long known of the existence of faults in Southeast Texas, only recently have UH scientists produced a comprehensive map pinpointing the locations of the faults. A Houston-area map showing active surface faults is available at http://www.uh.edu/news-events/archive/nr/2008/04april/geological-faultsph.html.

While the ground moving beneath Houstonians feet is not felt at the magnitude of recent earthquakes in San Antonio and Illinois, this shaky ground could mean trouble for buildings, roads and pipelines located on one of these hundreds of faults traversing the regions surface.

These shifting fault lines originated millions of years ago during the formation of the Gulf of Mexico, Khan said. While they are not the kinds that wreak havoc in earthquake-prone California and now the Midwest, they can move up to 1 inch a year, causing serious damage over the course of several years to buildings and streets that straddle a fault line. Additionally, structures on the subsiding side of the fault line could be more susceptible to flooding due to the lower elevation over time......... Posted by: Tyler      Read more         Source

April 24, 2008, 8:58 PM CT

Injecting Sulfate Particles into Stratosphere

A much-discussed idea to offset global warming by injecting sulfate particles into the stratosphere would have a drastic impact on Earth's protective ozone layer, new research concludes.

The study, led by Simone Tilmes of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., warns that such an approach would delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic.

The study results are published recently in the journal Science Express. The research was funded by the National Science Foundation (NSF), NCAR's principal sponsor, as well as by NASA and other agencies.

"Our research indicates that trying to artificially cool off the planet may be a perilous endeavor," Tilmes says. "While climate change is a major threat, this solution could create severe problems for society".

"The challenges of global warming mitigation are extremely complex," said Cliff Jacobs, program director in NSF's Division of Atmospheric Sciences. "Continued investment in basic research will allow the most cost-effective solutions--and those of the most benefit to society--to be found".

Climate scientists, concerned that society is not taking sufficient action to prevent significant changes in climate, have studied various "geoengineering" proposals to cool the planet and mitigate the most severe impacts of global warming......... Posted by: Tyler      Read more         Source

April 24, 2008, 8:55 PM CT

Earthquake in Illinois

To the surprise of a number of, the earthquake on April 18, 2008, about 120 miles east of St. Louis, originated in the Wabash Valley Fault and not the better-known and more-dreaded New Madrid Fault in Missouri's bootheel.

The concern of Douglas Wiens, Ph.D., and Michael Wysession, Ph.D., seismologists at Washington University in St. Louis, is that the New Madrid Fault may have seen its day and the Wabash Fault is the new kid on the block.

The earthquake registered 5.2 on the Richter scale and hit at 4:40 a.m. with a strong aftershock occurring at approximately 10:15 a.m. that morning, followed by lesser ones in subsequent days. The initial earthquake was felt in parts of 16 states.

"I think everyone's interested in the Wabash Valley Fault because a lot of the attention has been on the New Madrid Fault, but the Wabash Valley Fault could be the more dangerous one, at least for St. Louis and Illinois," said Wiens, professor of earth and planetary sciences in Arts & Sciences. "The strongest earthquakes in the last few years have come from the Wabash Valley Fault, which needs more investigation."

Wiens said that seismologist Robert Hermann of Saint Louis University, Gary Pavils of Indiana University, and several geologists including Steven Obermeir of the U.S. Geological Survey (USGS), have made studies of the Wabash Valley Fault. Pavils also has run a dense local array of stations and recorded a number of very small earthquakes at the Wabash Valley Fault. Hermann has studied the 1968 magnitude 5.5 earthquake, the largest ever recorded there. Obermeir and others have found disturbed sediments from prior earthquakes along the fault with estimated magnitudes of about 7 on the Richter scale over the past several thousand years......... Posted by: Tyler      Read more         Source

April 21, 2008, 8:21 PM CT

The Antarctic deep sea gets colder

The Antarctic deep sea gets colder, which might stimulate the circulation of the oceanic water masses. This is the first result of the Polarstern expedition of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association that has just ended in Punta Arenas/Chile. At the same time satellite images from the Antarctic summer have shown the largest sea-ice extent on record. In the coming years autonomous measuring buoys will be used to find out whether the cold Antarctic summer induces a new trend or was only a "slip".

The Polarstern expedition ANT-XXIV/3 was dedicated to examining the oceanic circulation and the oceanic cycles of materials that depend on it. Core themes were the projects CASO (Climate of Antarctica and the Southern Ocean) and GEOTRACES, two of the main projects in the Antarctic in the International Polar Year 2007/08.

Under the direction of Dr. Eberhard Fahrbach, Oceanographer at the Alfred Wegener Institute, 58 researchers from ten countries were on board the research vessel Polarstern in the Southern Ocean from 6 February until 16 April, 2008. They studied ocean currents as well as the distribution of temperature, salt content and trace substances in Antarctic sea water. „We want to investigate the role of the Southern Ocean for past, present and future climate," chief scientist Fahrbach said. The sinking water masses in the Southern Ocean are part of the overturning in this region and thus play a major role in global climate. „While the last Arctic summer was the warmest on record, we had a cold summer with a sea-ice maximum in the Antarctic. The expedition shall form the basis for understanding the opposing developments in the Arctic and in the Antarctic," Fahrbach said......... Posted by: Tyler      Read more         Source

April 21, 2008, 8:05 PM CT

Arctic Ice More Vulnerable to Sunny Weather

The shrinking expanse of Arctic sea ice is increasingly vulnerable to summer sunshine, new research concludes. The study, by researchers at the National Center for Atmospheric Research (NCAR) and Colorado State University (CSU), finds that uncommonly sunny weather contributed to last summer's record loss of Arctic ice, while similar weather conditions in past summers do not appear to have had comparable impacts.

The study, which draws on observations from instruments on a new group of NASA satellites known as the "A-Train," will be published tomorrow in Geophysical Research Letters. It was funded by NASA and the National Science Foundation, which is NCAR's principal sponsor.

"In a warmer world, the thinner sea ice is becoming increasingly sensitive to year-to-year variations in weather and cloud patterns," says NCAR's Jennifer Kay, the lead author. "A single uncommonly clear summer can now have a dramatic impact".

The findings indicate that summer sunshine in the Arctic produces more pronounced melting than in the past, largely because there is now less ice to reflect solar radiation back into space. As a result, the presence or absence of clouds now has greater implications for sea ice loss.

Satellite data offer clues to record-shattering 2007 melt........ Posted by: Tyler      Read more         Source

April 21, 2008, 6:17 PM CT

How climate change impacts food production

The old adage, We are what we eat, may be the latest recipe for success when it comes to curbing the perils of global climate warming. Despite the recent popular attention to the distance that food travels from farm to plate, aka food miles, Carnegie Mellon scientists Christopher L. Weber and H. Scott Matthews argue in an upcoming article in the prestigious Environmental Science & Technology journal that it is dietary choice, not food miles, which most determines a households food-related climate impacts.

Our analysis shows that despite all the attention given to food miles, the distance that food travels is only around 11% of the average American households food-related greenhouse gas emissions, said Weber, a research professor in Carnegie Mellons department of civil and environmental engineering and engineering and public policy.

The scientists report that fruit, vegetables, meat and milk produced closer to home rack up fewer petroleum-based transport miles than foods trucked cross country to your table. Yet despite the large distances involvedthe average distance traveled for food in the U.S. is estimated at 4,000-5,000 miles the large non-energy based greenhouse gas emissions linked to producing food make food production matter much more than distance traveled......... Posted by: Tyler      Read more         Source

April 17, 2008, 7:33 PM CT

Dam removal increases property values

Two new studies appearing in Contemporary Economic Policy explore the impact of dam removal on local property values and find that property values increase after dams are removed.

Lynne Y. Lewis, Ph.D., of Bates College and scientists utilized geographic information systems mapping software to examine the effects of small hydropower dams on property values in Maine. The study examined the effects on property values of the Edwards dam in Augusta which was removed in 1999, as well as two other existing dams located elsewhere on the Kennebec River.

The study observed that there is a penalty for being near the dam sites. Properties near the dams have lower value than properties further away. However, this penalty has shrunk substantially since the removal of Edwards Dam. The penalty for being close to the two existing dams is approximately three times larger than the penalty for being close to the site of the former Edwards Dam.

Removal of the Edwards dam has also had significant positive effects on fisheries and recreational value of the Kennebec River. Since its removal, commercially important fish have returned to the river above the dam site. Recreation on the river including fly fishing, canoeing, and kayaking has also increased.

A study led by Bill Provencher, Ph.D. of the University of Wisconsin-Madison also examined the impact of small dam removal on property values. His work focused on small dam removal in south-central Wisconsin. The study applied statistical techniques to market sales data to determine the relative contribution to property values. The results are quite similar to those found by Lewis. Residential property by a river but not by a dam is more valuable than identical property located by a dam......... Posted by: Tyler      Read more         Source