bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new window opens on the Arctic
Authors: Francis Jennifer A. , Schweiger Axel J. 
Published: October 2006

The Arctic, which was once often excluded from global displays of geophysical fields, has moved to the forefront of climate research. Global climate models (GCMs) have long predicted that the high latitudes would be the bellwether of the climates response to anthropogenic modifications because of strong feedback mechanisms involving snow, sea ice, clouds, and radiation. Many questions and uncertainties surround parameterizations of polar processes in GCMs, however, and tremendous differences exist between model simulations for present‐day climate conditions [e.g., Gates et al., 1999],to say nothing of future climate predictions.In recognition of these issues and the potential contribution that satellite data could make to addressing them, NASA and the National Oceanic and Atmospheric Administration (NOAA) initiated the Pathfinder program (see Web site: http://xtreme.gsfc.nasa.gov/pathfinder/). The TIROS Operational Vertical Sounder (TOVS) Polar Pathfinder data set, produced with funding from this program, provides a new source of information about the Arctic surface and atmosphere that may offer insight into the complex processes that control the Arctic climate system.
UNAVCO Conference explores advances in volcanic geodesy
Authors: Stein Seth , Hamburger Michael , Meertens Charles , Dixon Timothy , Owen Susan 
Published: October 2006

Volcanic eruptions are among Earth's most spectacular surface phenomena. However, attempts to understand their basic physics face the challenge that the key processes occur at great depth and are difficult to observe. Thus volcanologists have been interested for years in using ground deformation measurements to study active volcanoes and predict their behavior during extended volcanic crises, such as the dramatic six weeks in 1980 between the initial and major eruptions of Mt. Saint Helens.The advent of new technologies in recent years—in particular the Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (INSAR)—has shown potential for significant advances in volcano studies. Progress in this direction was explored at a conference organized by the University Navstar Consortium (UNAVCO) on September 15–17, 1999, with financial support from the National Science Foundation (NSF), NASA, and the U.S. Geological Survey (USGS). The meeting aimed to assess the status of various geodetic technologies and their potential to address crucial scientific and social needs in volcanic science and monitoring, as well as to develop recommendations on ways to spur further progress in these areas.
Seismic evidence for volcanic activity discovered in central Arctic
Authors: Müller Christian , Jokat Wilfried 
Published: October 2006

An earthquake swarm of well over 200 events was recently detected along the Gakkel Ridge in the central Arctic Ocean. The swarm occurred between January and August of 1999 and was localized between longitudes 70°E and 90°E (Figure 1a ) . Over the past few decades, only a few randomly clustered earthquakes had been detected along the 1800‐km‐long ridge.Evidence from moment tensor solutions indicates that this swarm originated as a tectonic rifting episode, with double‐couple normal faulting, and transitioned in early March of 1999 to more volcanic origin with strongly non‐double‐couple events. This is the first direct evidence of recent volcanic activity in the high Arctic. Because seismic activity is low at slow and ultra‐slow spreading ridges, the swarm provides an unprecedented opportunity to investigate crustal processes along the ridge.
[Commnet on “Seismic predictors of El Niño revisited”] Comment on an atmospheric stochastic trigger for El Niño
Authors: Hunt A. G. 
Published: October 2006

A recent Eos article [Walker, 1999] describes a correlation between El Niño occurrence and seismicity along the most rapidly spreading portion of the East Pacific Rise, located below the eastern Pacific atmospheric high‐pressure zone most strongly influenced by El Niño.The correlation between seismicity and El Niño is accentuated by seismic precursors to the development of an El Niño. Walker suggests that a trigger for El Niño has not been unambiguously identified. Walker concludes that increased seismicity is likely to be associated with enhanced heat flow, which might ultimately trigger, or be connected with a trigger for, El Niño.Assuming that a correlation between seismicity and El Niño does exist, other explanations might be found, and one is suggested here to be at least more likely, if also improbable. Changes of sea level resulting from El Niño can induce small crustal stresses, which in an area of intense seismicity may have a small effect on earthquake statistics or trigger an earthquake that was about to happen anyway While I suspect that the counter‐proposal is, by itself, insufficient cause to discuss the correlation further, this argument is strengthened by the known correlation between reservoir filling and increased seismicity [Gupta and Chandha, 1995].The main problem with my counter‐argument is that the changes in sea level resulting from El Niño are only tens of centimeters, resulting in stresses of less than .lbar. Probably no seismologist would be comfortable with the suggestion that such a small stress could materially affect earthquake frequencies, even in an area with exceptionally high seismicity.The counterproposal is based on the statistics of global temperature and understanding the role of El Niño therein.
Turkish earthquakes reveal dynamics of fracturing along a major strike‐slip fault zone
Authors: Çemen Ibrahim , Gökten Ergun , Varol Baki , Kiliç Recep , Özaksoy Volkan , Erkmen Cenk , Pinar Ali 
Published: October 2006

During the last 5 months of 1999, northwestern Turkey experienced two major earthquakes along the North Anatolian Fault Zone (NAFZ). The first earthquake struck the country at 3:01 A.M. local time on August 17, and caused extensive damage in the towns of Yalova, Gölcük, Izmit, Adapazari, and Düzce (Figure 1). The second earthquake occurred at 6:57 P.M. local time on November 12 and caused damage mostly in Düzce and Kaynasli.The 7.4‐Mw main shock of the August 17 Izmit earthquake was centered at 40.702°N, 29.987°E and originated at a depth of 17 km. The center was about 11 km southeast of Izmit, a major industrial town (Figure 1). The earthquake was a devastating natural disaster that claimed close to 20,000 lives and left more than 100,000 people homeless.
Global lightning acquisition system installed
Authors: Füllekrug Martin , Constable Steven , Heinson Graham , Sato Mitsuteru , Takahashi Yukihiro , Price Colin , Williams Earle 
Published: October 2006

A global network of seven time‐synchronized, high‐precision magnetometers around the world is ready to triangulate individual lightning flashes on planet Earth to monitor the temporal and spatial evolution of global lightning activity.This global network of magnetometers is able to detect the electromagnetic radiation of distant lightning flashes and makes possible remote sensing of the temporal evolution and spatial migration of global lightning activity [Füllekrug and Constable, 2000]. These results have led to international interest in a new measurement campaign with a large network of high‐precision magnetometers. The magnetic field changes are measured with ∼10‐14 Tesla accuracy (which corresponds to ∼10‐7% of the main geomagnetic field). The Global Positioning Satellites (GPS) provide time alignment of 0.00002 seconds between two measurement stations at antipodal distances (20×103, km), and the digital equipment makes possible continuous, high‐frequency recordings with 2000 samples per second.
Extensive magmatic and hydrothermal activity documented in Manus Basin
Authors: Auzende Jean‐Marie , Ishibashi Jun‐Ishiro , Beaudoin Yannick , Charlou Jean‐Luc , Delteil Jean , Donval Jean‐Pierre , Fouquet Yves , Ildefonse Benoit , Kimura Hiroyuki , Nishio Yoshiro , Radford‐Knoery Joel , Ruøllan Etienne 
Published: October 2006

In 1995, a joint French‐Japanese cruise (ManusFlux) explored the Manus Spreading Center and some sites of the South Eastern Rift in the Manus Basin off the coast of Papua New Guinea (Figure 1) with the Japanese submersible [Auzende et al., 1996; Gamo et al., 1997]. In the framework of this joint project, called New STARMER, the French and Japanese teams completed the Manaute cruise with the R/V LAtalante and the Ifremer submersible Nautile in April and May 2000.The Manaute cruise explored and sampled volcanic and hydrothermal sites in the eastern part of Manus Basin and on the spreading axis of the Western Ridge (WR). The eastern part of the Manus Basin (Figure 2) was interpreted as a stretched‐back arc basin crust showing alternatively elongated ridges and isolated volcanoes where accretion and hydrothermal activity are distributed [Martinez and Taylor, 1996; Binns et al., 1993].
Nutrient over‐enrichment implicated in multiple problems in U.S. waterways
Authors: Showstack Randy 
Published: October 2006

As scientists gathered to discuss the increasing problem of nutrient over‐enrichment of coastal and other water bodies during an October 11–13 symposium in Washington, D.C., federal, state, and tribal negotiators 1600 km away in Baton Rouge, Louisiana, reached what could be a landmark agreement to attempt to reduce the hypoxic “dead zone” region in the Mississippi River watershed and the Gulf of Mexico.That agreement, hammered out by the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force and announced on October 11, calls for reducing the 5‐year running average of the aerial extent of the hypoxic zone to less than 5000 square km by 2015. The mid‐summer aerial extent for bottom‐water hypoxia has exceeded 10,000 square km each year since 1993, and it was more than 20,000 square km in 1999.
Fifty‐year record of north polar temperatures shows warming
Authors: Kahl Jonathan D. W. , Jansen Mark , Pulrang Martin A. 
Published: October 2006

The Arctic Ocean has long been at the center of the global warming debate, since a significant reduction in sea ice could alter the Earth's radiation balance, as well as modify global atmospheric circulation. According to an August 19, 2000, report in The New York Times, passengers aboard a Russian icebreaker‐turned‐cruise ship observed a “mile‐wide” patch of ice‐free ocean at the pole. This observation immediately prompted speculation that global warming is already melting the polar icecap.Two types of open water commonly occur throughout the Arctic pack ice. The linear features, called leads, and curvilinear features, called polynyas, are not necessarily cause for concern. However, the overall extent of Arctic sea ice has decreased in recent decades and, hence, the issue of polar warming is of broad environmental interest.
Iridium satellites help map electrical currents in space
Authors: Showstack Randy 
Published: October 2006

The satellite constellation of Iridium LLC, which filed for Chapter 11 bankruptcy in 1999 after it failed to win enough business for its commercial satellite communications services, is still orbiting at an altitude of about 780 kilometers. Now, however, the satellites are helping to write a new chapter in understanding space weather.Magnetometers onboard each of the system's 66 polar‐orbiting satellites are working in conjunction with the high‐frequency, multinational Super Dual Auroral Radar Network, or SuperDARN, to provide the first continuous measurements of electrical currents between Earth's upper atmosphere and space. These tools also are generating the first global maps of electrical power flowing into the polar upper atmosphere.
New map reveals origin and geology of North American mid‐continent rift
Authors: Cannon W. F. , Daniels D. L. , Nicholson S. W. , Phillips J. , Woodruff L. G. , Chandler Val W. , Morey G. B. , Boerboom T. , Wirth K. R. , Mudrey M. G. 
Published: October 2006

New aeromagnetic data from the north central United States are helping geophysicists and geologists better understand the 1.1‐billion‐year‐old mid‐continent rift, one of the fundamental components of the Precambrian basement of North America.A detailed geologic map of part of the rift is being made and a myriad of new details concerning the history of rift subsidence, volcanism, sedimentation, and inversion are being deciphered. The data are also helping to establish a link between well‐known parts of the rift in the Lake Superior region, where exposures of rift‐related rocks are abundant and where a comprehensive geophysical data base has existed for more than a decade, and the buried extension of the rift to the southwest. Scientists from the U.S. Geological Survey (USGS), the Minnesota Geological Survey the Wisconsin Geological and Natural History Survey and Macalester College are using the new data in conjunction with field and laboratory investigations in a joint study that promises to produce new insights into the history and formation of the rift.
[Comment on “IPCC Report cautiously warns of potentially dramatic climate change impacts”] U.S. Administration reviewing Climate Policy
Authors: Pielke Roger A. 
Published: October 2006

In a news article in the February 27, 2001 issue [Showstack, 2001] Mike MacCracken, a scientist with the U.S. Global Change Research Program, was quoted as supporting the view that land‐use change is an important issue with respect to climate change.However, MacCracken is also quoted as stating that, “But for the 21st century, the kinds of changes that are projected for atmospheric composition are going to swamp anything due to land cover change.”
Vote using the Web
Authors: Schmoltner Anne‐Marie 
Published: October 2006

In an effort to increase the strength of AGU by increasing participation in voting, you will be able to cast your ballot for AGU officers on the Web this year. The Tellers Committee is working with an experienced firm, election.com, to develop procedures for conducting AGU's first electronic election in November and December 2001. You will be able to cast your votes for the officers of your choice, among the 62 candidates, by going to a secure Web site, or by requesting a paper ballot.An amendment to the District of Columbia law now permits non‐profit organizations incorporated in Washington, D.C. to conduct elections using electronic voting. AGU was instrumental in getting the amendment adopted by the Council of the District of Columbia in spring 2001.
New computer promises to accelerate climate change research
Authors: Showstack Randy 
Published: October 2006

The acquisition of a new IBM SP supercomputer and advanced technologies, announced on November 9 by a Boulder, Colorado‐based research organization, could accelerate research into global and regional climate change, short‐ and long‐range weather prediction, atmospheric chemistry, space weather, and other areas.The equipment, announced by the National Center for Atmospheric Research (NCAR) and its parent organization, the University Corporation for Atmospheric Research (UCAR), will provide atmospheric scientists with access to new computational, storage, and communications capabilities. The U.S. National Science Foundation (NSF) purchased the machine for use at NCAR to advance geoscience research.
Panel urges measures to minimize effects of future abrupt climate changes
Authors: Showstack Randy 
Published: October 2006

Future abrupt climate changes are likely, according to a new report issued by the U.S. National Research Council (NRC),and research into their causes, patterns, and probability is needed to help minimize potentially large impacts on societies, ecosystems, and natural resources such as water.The December 10 report, “Abrupt Climate Changes: Inevitable Surprises,” notes that abrupt regional or global climate changes that may occur within the span of a human generation could be triggered either by natural or anthropogenic causes, including global warming. Such changes could affect temperature, precipitation, evaporation, and extreme weather events.
Survey of “emerging contaminants” in U.S. streams indicates need for further research
Authors: Showstack Randy 
Published: October 2006

The first nationwide reconnaissance of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in U.S. streams has found one or more targeted compounds in 80% of the streams sampled. The U.S. Geological Survey (USGS) study, released on 13 March, detected 82 of 95 specific compounds in the 139 streams sampled.Herbert Buxton, coordinator of the USGS Toxic Substances Hydrology Program, which conducted the study, said, “This is the first hard environmental occurrence information on a large number of environmental compounds on which we did not have information before.” Buxton said the findings may aid research on potential human and ecological effects from these compounds and on understanding in what concentrations the compounds occur individually and in combinations.
Optimizing Reservoir Resources: Including a New Model for Reservoir Reliability
Authors: Houck Mark H. 
Published: October 2006

Optimizing Reservoir Resources: Including a New Model for Reservoir Reliability is a fascinating blend of text and monograph with an unusual range of material. The first part is clearly textual and the second half reports on some very interesting research done for the Institute of Water Resources of the U.S. Army Corps of Engineers.The successive chapters are evolutionary; one leads to another and offers a base for the subjects covered subsequently Part I contains five chapters on relatively established topics in water resources systems. These are the “text” chapters in the text‐monograph combo referred to above.
Deep sea borehole observatories ready and capturing seismic waves in the western Pacific
Authors: Suyehiro Kiyoshi , Araki Eiichiro , Shinohara Masanao , Kanazawa Toshihiko 
Published: October 2006

Digital broadband seismometer networks and GPS networks are the recent sources of rapid progress in solid Earth geophysics. But they do not exist beneath the oceans. The lack of observatories in deep oceans that cover 71% of the Earth's surface has been considered a major deficiency in the seismic network by the scientific community. About 80% of the present plate boundary is located in the oceans and about 90% of seismic energy release is earthquakes beneath the sea floor, mostly at plate subduction zones.Ocean basins and continents that make up our environments are not mere superficial features. They are surface manifestations of plate tectonics, mantle mixing, and core‐mantle interactions invigorated by the recycling of the oceanic plates.
A new deep‐sea towed digital camera and multi‐rock coring system
Authors: Fornari Daniel J. ,   WHOI TowCam Group
Published: October 2006

Photographs of the sea floor provided some of the first clues about the abundance of life in the deep ocean, lava flows on the mid‐ocean ridge crest, and evidence for hydrothermal venting [e.g., Hersey, 1967; Heezen and Hollister, 1971; Ballard and Moore, 1977; Lonsdale, 1977]. These direct observations of the ocean floor are critical to understanding the physical, chemical, and biological processes occurring there.Last year, a team of engineers at the Woods Hole Oceanographic Institution (WHOI), in collaboration with engineers at DeepSea Power and Light (DSPL) of San Diego, California, designed and successfully built and tested a new, digital deep‐sea camera and multi‐rock coring system. The system has been used during three expeditions thus far: the East Pacific Rise at 9°50′N, the Galápagos Rift at 86°–89°W and most recently to the Hess Deep in the equatorial eastern Pacific. To date, it has acquired ˜20,000 digital sea floor images and 50 volcanic glass chip samples during 20 lowerings.
Investigating a 65‐Ma‐old smoking gun: Deep drilling of the Chickxulub Impact Structure
Authors: Dressler B. O. , Sharpton V. L. , Morgan J. , Buffler R. , Moran D. , Smit J. , Stöffler D. , Urrutia J. 
Published: October 2006

The Phanerozoic paleontological record is marked by several biological extinction events. One of them, at the Cretaceous/Tertiary (K/T) boundary, was responsible for the demise of about 50% of genera and 75% of species, including the dinosaurs. These drastic and abrupt changes in the development of life on Earth puzzled paleontologists in the past. Many a cause was put forward to account for them, amongst them climate changes, disease, or overspecialization.About 20 years ago, Alvarez et al. [1980] discovered a high iridium concentration in an Italian K/T boundary clay layer.They proposed that the iridium was derived from an extra‐terrestrial impact 65 Ma ago, and that the impact was the cause for the K/T boundary extinctions. The iridium layer was subsequently found at K/T boundary locations worldwide. Further evidence for a K/T impact came from the discovery of shocked quartz, nano‐diamonds, glass spherules, and nickel‐rich spinels in microkrystites in the iridium‐rich layer. There was evidence for an impact event, but no crater.
An Introduction to Seismology, Earthquakes, and Earth Structure
Authors: Thurber Clifford 
Published: October 2006

S. Stein and M. Wysession's An Introduction to Seismology, Earthquakes, and Earth Structure is the textbook I've been waiting for. It combines the pedagogical strengths of Introduction to Seismology by P. Shearer (1999) and the breadth of coverage of Modern Global Seismology by T. Lay and T. Wallace (1995). The “price” of this combination is a rather lengthy text, but it is so well written that the length can be easily forgiven.At first glance, An Introduction to Seismology Earthquakes, and Earth Structure appears to follow a very traditional path, beginning with a nice overview chapter on the relevance of seismology, followed by chapters on seismic waves that include stress and strain basics, Earth structure, earthquake sources, and seismology and plate tectonics. On closer inspection, though, the reader will find many chapter sections that are rather novel. Included among these are waves on a string, an excellent way to introduce students to the complexity of seismic waves; earthquake geodesy which establishes the important connection between seismology and deformation studies; and plate kinematics, a clearly presented “short‐course” on plate motion studies. These sections, and others like them, significantly enhance the text. The latter two in particular help give the book a broader perspective that is rare in standard seismology texts.
When Earth's freezer door is left ajar
Authors: Gildor Hezi 
Published: October 2006

The expected response of the Earth's cryosphere to global warming is a critical open research area in which model certainty is still unsatisfactory On the other hand, past climate history can teach us quite a bit. If one had returned from a vacation to find that the freezer door was left partially open and ice had collected in it, one would have learned an important climate lesson: ice does not form when conditions are merely cold, but when there is a supply of warm, moist air to a sufficiently cold environment.While it is good practice to close one's freezer door and not experience this climate lesson personally, numerous observations and model results demonstrate that the large ice sheets that developed during past ice ages grew when the climate was relatively warm, and therefore moist. One must conclude that statements such as “…glaciers grow when climate is cold, not warm and moist” [Rahmstorf, 2002] contradicts a large body of scientific evidence, observations, and dynamical arguments. We now understand that the ocean also plays an important role in this feedback due to the role of sea ice in glacial dynamics.