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1. |
Antarctic mass balance and sea level change |
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Eos, Transactions American Geophysical Union,
Volume 74,
Issue 50,
1993,
Page 585-586
Charles R. Bentley,
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摘要:
The Antarctic ice, remote as it is, has the potential to affect coastal communities and habitats around the world, because any change in its mass will directly affect mean sea level. Despite all the study of the ice sheet in the last several decades, however, it is still uncertain whether the ice sheet is growing, shrinking, or unchanging in mass. The most recent studies are contradictory—glaciological evidence from the continent suggests that the ice sheet is slowly growing, oceanographic evidence around the continent suggests that it is shrinking, and indirect satellite evidence relating to changes in mass distribution over the surface of the globe suggests that changes of either sign must be small.The glaciological evidence has most recently been summarized byBentley and Giovinetto[1991]. By analyzing all available measurements on the rate of snow accumulation on the ice sheet (the mass input) and the mass flux across the boundary between the land‐based and floating margins of the ice sheet (the mass output), they came to the conclusion that there is a net gain of about 200 Gt yr−1, that is, a sea‐level lowering of about 0.5 mm yr−1. The data cover the large drainage systems that encompass the vast interior plateaus where the mass input rates are small. Much less is known about more limited coastal systems characterized by higher specific mass input rates. Nevertheless, it seems unlikely that these smaller regions could be losing mass rapidly enough to make up for the mass gain over the majority of the
ISSN:0002-8606
DOI:10.1029/93EO00653
年代:1993
数据来源: WILEY
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2. |
In Memoriam |
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Eos, Transactions American Geophysical Union,
Volume 74,
Issue 50,
1993,
Page 586-586
Anonymous,
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摘要:
John W . Vanderwilt,95, died on November 15, 1992. He joined AGU (Volcanology, Geochemistry, and Petrology) in 1947.Andrew J. Gratzdied recently at age 31. He had been a member of AGU (Tectonophysics) since 1983.
ISSN:0002-8606
DOI:10.1029/EO074i050p00586-02
年代:1993
数据来源: WILEY
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3. |
Global Younger Dryas? |
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Eos, Transactions American Geophysical Union,
Volume 74,
Issue 50,
1993,
Page 587-589
R. Alley,
G. Bond,
J. Chappellaz,
C. Clapperton,
A. Del Genio,
L. Keigwin,
D. Peteet,
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摘要:
Researchers examining the Younger Dryas (YD) paleoclimatic oscillation were brought together at an international, interdisciplinary workshop sponsored by PAGES (Past Global Climate Changes) and the Lamont‐ GISS (Goddard Institute for Space Studies) Climate Center and organized by D. Peteet. The workshop was held April 29–30 at Lamont‐Doherty Earth Observatory in Palisades, N.Y.The YD event was a major return to cold conditions that occurred approximately 11‐10,000 radiocarbon years B.P., after the warming trend following the last ice age. This pronounced and rapid cooling, identified almost a century ago in terrestrial records, continues to challenge our thinking about how various components of the biosphere, ocean, atmosphere, and cryosphere interact on short time scales. Because it is clearly evident in terrestrial, marine, and ice core repositories, the evidence provides an intriguing example of past climate fluctuation that is relevant for future climate
ISSN:0002-8606
DOI:10.1029/93EO00499
年代:1993
数据来源: WILEY
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4. |
Recommendations for NASA's Space Physics Data System |
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Eos, Transactions American Geophysical Union,
Volume 74,
Issue 50,
1993,
Page 589-590
Rikhi Sharma,
Ray Walker,
Jim Willett,
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摘要:
Approximately seventy‐five scientists gathered at Rice University in Houston, Tex. from June 1 to 3 for a community‐wide workshop on NASA's Space Physics Data System (SPDS). The purpose of the workshop was to consider community needs for data access and to make recommendations to guide the Space Physics Division (SPD) in managing space physics data in the 1990s and beyond.The workshop was organized into four panels: policy, data issues, data systems, and software. Participants reviewed the SPDS concept document prepared by the SPDS Steering Committee and were asked to approve or give an alternative view regarding any or all ideas discussed in the document, through one or more of the appropriate panels. The panels were also charged with identifying and prioritizing key requirements in their area of interest and commenting on relevant issues of implementat
ISSN:0002-8606
DOI:10.1029/93EO00538
年代:1993
数据来源: WILEY
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5. |
Symposium probes materials science approaches in geophysics |
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Eos, Transactions American Geophysical Union,
Volume 74,
Issue 50,
1993,
Page 590-591
Reid F. Cooper,
Joanne T. Fredrick,
David J. Green,
Andreas K. Kronenberg,
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摘要:
The mechanisms of fracture and flow in rocks and ceramics are remarkably similar. As a result, studies of the mechanical properties of Earth materials that ultimately govern the behavior of the lithosphere have benefitted from mineral and rock physics approaches resembling those taken in the study of structural ceramics. Laboratory studies of fracture propagation and frictional sliding in rocks have led to advances in our understanding of earthquake mechanics [e.g.,Tullis,1986;Segall,1991] much as experimental studies of engineering materials have aided in the prediction of failure and wear of critical structural components.Studies of mineral plasticity and ductile flow of rocks [e.g.,Evans and Dresen,1991] have revealed that nonlinear time‐dependent rheologies, as first described for metals and ceramics, govern mechanical response at high temperatures and pressures with pronounced effects on the scaling and evolution of continental collisions [England et al,1985;Houseman and England,1993]. Studies of the mechanical and transport properties of partial melts and glass ceramics [Cooper,1990] are now providing insights into the delivery of melts to active ridge axes [e.g.,Phipps Morgan,1991]. Investigations of phase transformations in silicate and oxide systems have revealed mechanisms that are both thermally driven and stress‐induced, and experiments designed to examine phase transformations under nonhydrostatic stresses have provided insight into the source mechanisms of deep‐focus earthquakes [Kirby et al.,1991;Green et al.,
ISSN:0002-8606
DOI:10.1029/93EO00518
年代:1993
数据来源: WILEY
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