Measuring Earth orientation with the global positioning system     

Adam P. Freedman 《Journal of Geodesy》1991,65(1):53-65

Summary A globally distributed network of high-precision receivers which obtain data from the full Global Positioning System (GPS) configuration of 18 or more satellites may soon become an efficient and economical method for the rapid determination of short-term variations in Earth orientation. A covariance analysis has been performed to evaluate the errors associated with GPS monitoring of Earth orientation. Earth orientation parameters were modeled either as constants over observing windows of various lengths, or as stochastic process-noise variables. The sensitivity of Earth orientation estimates to systematic errors in selected model parameters was also examined. GPS measurements appear to be highly competitive with those from other techniques, and have the potential to generate nearly continuous centimeter-level Earth orientation information to aid both spacecraft navigation and the study of high-frequency Earth orientation-related processes.  相似文献   

Book reviews     

Allan M. Rubin  Gerardo G. Tango  Jeremy Bloxham  Stanislaw Wybraniec  Adam Łyszkowicz  Gary A. Robbins  Benoit Cushman-Roisin  David S. Gutzler  Carlos Lozano  Hanna Pawłowska 《Pure and Applied Geophysics》1991,137(1-2):147-174

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The magnetotelluric phase over 2-D structures     

Gaston Fischer  L. Szarka  A. Adam  J. T. Weaver 《Geophysical Journal International》1992,108(3):778-786

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Mid-Holocene evolution of a tidal basin in the western Netherlands: a model for future changes in the northern Netherlands under conditions of accelerated sea-level rise?     

Adam J.F. van der Spek  Dirk J. Beets 《Sedimentary Geology》1992,80(3-4):185-197

A scenario for the future development of the Dutch Wadden Sea is derived from an evolutionary model for tidal basins during a rise in sea level. The model is based on the evolution of the Atlantic/Subboreal Holland tidal basin, between 7000 BP and 3500 BP. It emphasizes the balance between the storage capacity created by a sea-level rise and the amount of sediment available.

If the rate of relative sea-level rise exceeds the rate of sediment supply, the innermost (central) portions of the basin will not receive sufficient sediment for an intertidal morphology to be preserved. Eventually, sand will be deposited only in tidal channels and in the flood-tidal delta through which the sediment is supplied, mud deposition will occur in the interchannel areas and salt marshes will disappear.  相似文献   

Crustal and Upper Mantle Research in Pannonian Basin by Electromagnetic Induction:A Review     

Adam A.Sopron  Hungary 《中国地质大学学报(英文版)》1992

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变形模型可区分度量   总被引：3，自引：0，他引：3  

陈永奇 Chrza.  A 《测绘学报》1993,22(1):19-24

在监测网设计阶段，变形体的变形特性一般不是完全清楚。因此，设计的监测方案应当能有效地和足够灵敏地区分几种可能的模型。本文研究了模型的可区分度量，所用的方法具有思路明确、清晰等特点，特别适用于在设计阶段设置指标。文中通过一个模拟网的分析和讨论，说明采用模型可区分度量作为设计准则的必要性。分析的结果还和Forstner法所得的结果进行初步的比较。  相似文献   

Archean of Greenland and Fennoscandia     

Pentti Hoelttae Victor Balagansky Adam A. Garde Satu Mertanen Petri Peltonen Alexander Slabunov Peter Sorjonen-Ward Martin Whitehouse 《《幕》》2008,31(1):13-19

The North Atlantic craton in southern West Greenland mainly consists of a tectonic collage of Mesoarchean continental crustal terranes, which were amalgamated at c. 2.7 Ga and are currently exposed at mid-crustal amphibolite to granulite facies levels. Tonalitic orthogneisses predominate, intercalated with slightly older tholeiitic to andesitic metavolcanic rocks and associated gabbro-anorthosite intrusive complexes. The North Atlantic craton also contains enclaves of Eoarchean, c. 3.86-3.6 Ga orthogneisses and supracrustal rocks including the Isua greenstone （or supracrustal） belt. This is the oldest known assemblage of rocks deposited at the surface of the Earth, comprising mafic pillow lavas, banded iron formations and metasedimentary schists with local disseminated graphite of possible biogenic origin. Eoarchean rocks have not been found in Kola and Karelia in Fennoscandia where most rocks are 2.9-2.7 Ga tonalitic-trondhjemitic-granodioritic orthogneisses with intercalated coeval greenstone belts and amphibolites. Mesoarchean 3.0-3.2 Ga rocks are found in the eastern and western parts of the Karelian province. Subduction-related rocks like the Iringora supra-subduction type ophiolite and basalt-andesite-dacite-rhyolite series volcanic rocks in many greenstone belts, as well as eclogites are found in the Archean of Fennoscandia. A clear distinction between Greenland and Fennoscandia is the abundance of 2.75-2.65 Ga igneous rocks in Fennoscandia which indicates that these two cratons had a separate evolution during the Neoarchean.  相似文献   

Trends in heat-related mortality in the United States, 1975–2004     

Scott C. Sheridan  Adam J. Kalkstein  Laurence S. Kalkstein 《Natural Hazards》2009,50(1):145-160

This study addresses the long-term trends in heat-related mortality across 29 US metropolitan areas from 1975 to 2004 to discern the spatial patterns and temporal trends in heat vulnerability. Mortality data have been standardized to account for population trends, and seasonal and interannual variability. On days when a city experienced an “oppressive” air mass, mean anomalous mortality was calculated, along with the likelihood that oppressive days led to a mortality response at least one standard deviation above the baseline value. Results show a general decline in heat-related mortality from the 1970s to 1990s, after which the decline seems to have abated. The likelihood of oppressive days leading to significant increases in mortality has shown less of a decline. The number of oppressive days has stayed the same or increased at most metropolitan areas. With US homes near saturation in terms of air-conditioning availability, an aging population is still significantly vulnerable to heat events.  相似文献   

Remote Sensing of Biologically Reworked Sediments: A Laboratory Experiment     

Annelies De Backer  Stefanie Adam  Jaak Monbaliu  Erik Toorman  Magda Vincx  Steven Degraer 《Estuaries and Coasts》2009,32(6):1121-1129

The present study aims to test the application of remote sensing to address the impact of bioturbation on physical sediment properties. Therefore, a laboratory experiment was developed, using microcosms mimicking a marine intertidal water–sediment interface to test the influence of Corophium volutator densities on sediment properties. Three main variables (water content, clay content, and mean grain size) were measured in three treatments (no Corophium, 5,000 Corophium per square meter, and 20,000 Corophium per square meter) after 16 days of bioturbation. Results obtained with conventional—destructive—techniques showed a significant increase of water content and a significant, but small decrease of clay content in the presence of Corophium. The remote sensing technique detected the impact of Corophium on water content as an increase in absorption at 1,450 nm, but was not able to detect the animal impact on clay content. This study demonstrates that remote sensing data could be significantly modified by bioturbation activities and that remote sensing can be applied in the laboratory to address the impact of bioturbation on sediment properties. This possibly opens new perspectives for long-term experiments concerning the role of bioturbation on sedimentary processes.  相似文献   

Computational validation of static and dynamic plate load testing   总被引：1，自引：1，他引：0  

Christoph Adam  Dietmar Adam  Fritz Kopf  Ivan Paulmichl 《Acta Geotechnica》2009,4(1):35-55

In this paper, the static load plate test and the dynamic load plate test by means of the light falling weight device are assessed utilizing numerical simulations. Simplified computational models of the tested subsoil and of the testing devices are developed, which capture the main effects of both the static and the dynamic load plate test. In extensive parametric studies, the impact of various subsoil conditions on the test results and several sources of error are evaluated and discussed. Computational test results of the static load plate test and of the dynamic load plate test are set in contrast to an effort to demonstrate the differences and the common features of the outcomes.  相似文献