Book reviews     

Wolf Tietze  Gerhard Kortum  W. R. Mead  T. K. Poiker  C. Paddick  George Kish  A. Njøs  H. Mensching  V. Haarmann  Uzo M. Igbozurike  M. M. Yoshino  Mushtaqur Rahman  Lage Wahlström  J. Connell  Kazimierz Dziewonski  Wayland R. Swain  J. Humlum  G. W. Lüttig  Haruko Kishimoto  Mai Britt E. Mørk 《GeoJournal》1982,6(3):270-280

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GPS/GNSS Current Bibliography     

Tomás?SolerEmail author 《GPS Solutions》2003,7(3):206-208

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A note on frame transformations with applications to geodetic datums   总被引：1，自引：0，他引：1  

Tomás?SolerEmail author  John?Marshall 《GPS Solutions》2003,7(1):23-32

Rigorous equations in compact symbolic matrix notation are introduced to transform coordinates and velocities between ITRF frames and modern GPS-based geocentric geodetic datums. The theory is general but, after neglecting higher than second-order terms, it is shown that the equations revert to the formulation currently applied in most major continental datums. We discuss several examples: the North American Datum of 1983 (NAD83), the European Terrestrial Reference System of 1989 (ETRS89), the Geodetic Datum of Australia of 1994 (GDA94), and the South American Geocentric Reference System (SIRGAS). Electronic Publication  相似文献   

Stable Eocene Magnetization Carried by Magnetite and Iron Sulphides in Marine Marls (Pamplona-Arguis Formation,Southern Pyrenees,Northern Spain)     

Larrasoaña  J.C.  Parés  J.M.  Pueyo  E.L. 《Studia Geophysica et Geodaetica》2003,47(2):237-254

In order to establish the magnetic carriers and assess the reliability of previous paleomagnetic results obtained for Eocene marine marls from the south Pyrenean basin, we carried out a combined paleo- and rock-magnetic study of the Pamplona-Arguis Formation, which crops out in the western sector of the southern Pyrenees (N Spain). The unblocking temperatures suggest that the characteristic remanent magnetization (ChRM) is carried by magnetite and iron sulphides. The ChRM has both normal and reversed polarities regardless of whether it resides in magnetite or iron sulphides, and represents a primary Eocene magnetization acquired before folding. Rock magnetic results confirm the presence of magnetite and smaller amounts of magnetic iron sulphides, most likely pyrrhotite, in all the studied samples. Framboidal pyrite is ubiquitous in the marls and suggests that iron sulphides formed during early diagenesis under sulphate-reducing conditions. ChRM directions carried by magnetic iron sulphides are consistent with those recorded by magnetite. These observations suggest that magnetic iron sulphides carry a chemical remanent magnetization that coexists with a remanence residing in detrital magnetite. We suggest that the south Pyrenean Eocene marls are suitable for magnetostratigraphic and tectonic purposes but not for studies of polarity transitions, secular variations and geomagnetic excursions, because it is difficult to test for short time differences in remanence lock-in time for the two minerals. The presence of iron sulphide minerals contributing to the primary magnetization in Eocene marine marls reinforces the idea that these minerals can persist over long periods of time in the geological record.  相似文献   

Spatially explicit measures of production of young alewives in Lake Michigan: Linkage between essential fish habitat and recruitment     

Tomas?O.?H??kEmail author  Edward?S.?Rutherford  Shannon?J.?Brines  Doran?M.?Mason  David?J.?Schwab  Michael?J.?McCormick  Timothy?J.?DeSorcie 《Estuaries and Coasts》2003,26(1):21-29

The identification and protection of essential habitats for early life stages of fishes are necessary to sustain fish stocks. Essential fish habitat for early life stages may be defined as areas where fish densities, growth, survival, or production rates are relatively high. To identify critical habitats for young-of-year (YOY) alewives (Alosa pseud oharengus) in Lake Michigan, we integrated bioenergetics models with GIS (Geographic Information Systems) to generate spatially explicit estimates of potential population production (an index of habitat quality). These estimates were based upon YOY alewife bioenergetic growth rate potential and their salmonine predators’ consumptive demand. We compared estimates of potential population production to YOY alewife yield (an index of habitat importance). Our analysis suggested that during 1994–1995, YOY alewife habitat quality and yield varied widely throughout Lake Michigan. Spatial patterns of alewife yield were not significantly correlated to habitat quality. Various mechanisms (e.g., predator migrations, lake circulation patterns, alternative strategies) may preclude YOY alewives from concentrating in areas of high habitat quality in Lake Michigan.  相似文献   

Paleohydrology of Andean saline lakes from sedimentological and isotopic records, Northwestern Argentina     

Blas Valero-Garcés  Antonio Delgado-Huertas  Norma Ratto  Ana Navas  Larry Edwards 《Journal of Paleolimnology》2000,24(3):343-359

The paleohydrological evolution of several high altitude, saline lakes located in the southernmost Altiplano (El Peinado and San Francisco basins, Catamarca province, NW Argentina) was reconstructed applying sedimentological, geochemical and isotopic techniques. Several playa lakes from the San Francisco basin (26° 56 S; 68° 08 W, 3800-3900 m a.s.l.) show evidence of a recent raise in the watertable that led to modern deposition of carbonate and diatomaceous muds. A 2 m - long core from El Peinado Lake (26° 29 59 S, 68°05 32 W, 3820 m a.s.l.) consists of calcitic crusts (unit 3), overlaid by an alternation of macrophyte-rich and travertine clast- rich, laminated muds (unit 2), and topped by travertine facies (unit 1). This sedimentary sequence illustrates a paleohydrological evolution from a subaerial exposure (unit 3) to a high lake stand (unit 2), and a subsequent smaller decrease in lake level (unit 1). The ¹³C_{organic matter}record also reflects the lake transgression between units 3 and 2. Although there is a general positive correlation between ¹⁸O_carbonate and salinity proxies (Na, Li and B content), the large data dispersion indicates that other factors besides evaporation effects control chemical and isotopic composition of lakewater. Consequently, the oxygen isotopic composition cannot be interpreted exclusively as an indicator of salinity or evaporation ratio. The degassing of CO₂ during groundwater discharge can explain the enriched ¹³C values for primary carbonates precipitated. The carbon budget in these high altitude, saline lakes seems to be controlled by physical rather than biological processes.The Altiplano saline lakes contain records of environmental and climatic change, although accurate ¹⁴C dating of these lacustrine sediments is hindered by the scarcity of terrestrial organic material, and the large reservoir effects. Sedimentologic evidence, a ²¹⁰Pb-based chronology, and a preliminary U/Th chronology indicate a very large reservoir effect in El Peinado, likely as a result of old groundwaters and large contributions of volcanic and geothermal ¹⁴C-free CO₂ to the lake system. Alternative chronologies are needed to place these paleorecords in a reliable chronological framework. A period of increased water balance in the San Francisco basin ended at about 1660 ± 82 yr B.P. (calendar yr U/Th age), and would correlates with the humid phase between 3000 and 1800 yr B.P detected in other sites of the southern Altiplano. Both, ²¹⁰Pb and preliminary U/Th dating favor a younger age for the paleohydrological changes in El Peinado. The arid period reflected by subaerial exposure and low lake levels in unit 3 would have ended with a large increase in effective moisture during the late 17th century. The increased lake level during deposition of unit 2 would represent the period between AD1650 - 1900, synchronous to the Little Ice Age. This chronological framework is coherent with other regional records that show an abrupt transition from more arid to more humid conditions in the early 17th century, and a change to modern conditions in the late 19th century. Although there are local differences, the Little Ice Age stands as a significant climatic event in the Andean Altiplano.  相似文献   

A new scheme for numerical modelling of flow and transport processes in 3D fractured porous media     

Andrés Peratta  Viktor Popov 《Advances in water resources》2006

The objective of this work is to develop a new numerical approach for the three-dimensional modelling of flow and transient solute transport in fractured porous media which would provide an accurate and efficient treatment of 3D complex geometries and inhomogeneities. For this reason, and in order to eliminate as much as possible the number of degrees of freedom, the fracture network, fractures and their intersections, are solved with a coupled 2D–1D model while the porous matrix is solved independently with a 3D model. The interaction between both models is accounted for by a coupling iterative technique. In this way it is possible to improve efficiency and reduce CPU usage by avoiding 3D mesh refinements of the fractures. The approach is based on the discrete-fracture model in which the exact geometry and location of each fracture in the network must be provided as an input. The formulation is based on a multidimensional coupling of the boundary element method-multidomain (BEM-MD) scheme for the flow and boundary element dual reciprocity method-multidomain (BE-DRM-MD) scheme for the transport. Accurate results and high efficiency have been obtained and are reported in this paper.  相似文献   

Glacier development and topographic context     

J. I. Lpez‐Moreno  D. Nogus‐Bravo  J. Chueca‐Cía  A. Julin‐Andrs 《地球表面变化过程与地形》2006,31(12):1585-1594

This paper analyses the topographic context of the remaining glaciated areas in the Maladeta Massif (Central Spanish Pyrenees). These ice‐covered surfaces have been incorporated into a geographic information system (GIS) in an attempt at correlating the presence of ice with a range of topographic variables obtained from a digital elevation model. The use of generalized additive models and binary regression tree models enabled us (i) to quantify the spatial variability in the distribution of glaciers attributable to characteristics of the local terrain, (ii) to investigate the interaction between the variables that account for the ice cover distribution and (iii) to map the probability of glacier development. Our results show that although the development of glaciers depends on regional climate conditions, the topographic context is of paramount importance in determining the location, extent, shape and recent evolution of each glacial body. Thus, the joint effect of altitude, exposure to incoming solar radiation, slope and mean curvature is able to explain more than 70 per cent of the observed variance. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

GPS/GNSS Current Bibliography     

Tomás Soler 《GPS Solutions》2006,10(1):63-66

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A summer and winter apportionment of particulate matter at urban and rural areas in northern France     

F. Ledoux  L. Courcot  D. Courcot  A. Aboukaïs  E. Puskaric   《Atmospheric Research》2006,82(3-4):633

The apportionment of atmospheric aerosols undertaken in Northern France during two sampling campaigns allowed to determine the influence of the atmospheric contribution of a heavy industrialized urban center on the particulate matter composition at a nearby rural site. The concentrations of major components and trace elements sampled by bulk filtration have been determined on June–July 2000 and January–February 2001, and the comparison of these two campaigns shows very well the importance of wind directions. The sources of 10 trace elements (Al, Ba, Cu, Fe, K, Mn, Pb, Sr, Ti and Zn) and 7 major components (Cl⁻, NO₃⁻, SO₄²⁻, NH₄⁺, Na, Mg and Ca) are better identified by studying their elemental contribution at each sampling site according to wind sectors. This kind of study shows that the concentrations recorded at the urban sampling site are always higher than those observed at the rural site as well during the summer campaign (about + 35%) as during the winter campaign (+ 90%), because of the predominance of the W–NW wind sector, corresponding to the influence of the urban and industrialized areas.  相似文献