Reply to the comment by A. Revil on “Review of Self-potential methods in Hydrogeophysics” by L. Jouniaux et al. [C. R. Geoscience 341 (2009) 928–936]     

Laurence Jouniaux  Alexis Maineult  Véronique Naudet  Marc Pessel  Pascal Sailhac 《Comptes Rendus Geoscience》2010,342(10):810-813

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Benthic fluxes of copper,complexing ligands and thiol compounds in shallow lagoon waters     

Conrad S. Chapman  Gabriele Capodaglio  Clara Turetta  Constant M.G. van den Berg 《Marine environmental research》2009,67(1):17-24

Benthic fluxes of copper, copper complexing ligands and thiol compounds in the shallow waters of Venice Lagoon (Italy) were determined using benthic chambers and compared to porewater concentrations to confirm their origin. Benthic copper fluxes were small due to small concentration differences between the porewaters and the overlying water, and the equilibrium concentration was the same at both sites, suggesting that the sediments acted to buffer the copper concentration. Thiol fluxes were ～10 × greater at 50–60 pmol cm^?2 h^?1, at the two sites. Porewater measurements demonstrated that the sediments were an important source of the thiols to the overlying waters. The overlying waters were found to contain at least two ligands, a strong one, L1 (log K′_CuL1 = 14.2) and a weaker one, L2 (log K′_CuL2 = 12.5). The concentration of L1 remained relatively constant during the incubation and similar to that of copper, whereas that of L2 was in great excess of copper, its concentration balanced by porewater releases and breakdown, probably due to uptake by microorganisms, similar to that of the thiol compounds. Similarity of the thiol and L2 concentrations and similar complex stability with copper suggest that L2 was dominated by the thiols. The free copper concentration ([Cu´]) in the Lagoon waters was lowered by a factor of 10⁵ as a result of the organic complexation.  相似文献   

MOSES, a promising concept for marine research     

P. Y. Van den Berg  C. N. Van Bergen Henegouw  Th. C. J. Buisman 《Marine pollution bulletin》1994,29(6-12):569-572

The objective of the EUROMAR project Mobile Station for Environmental Services (MOSES) is the optimization, promotion and harmonization of the design and use of containerized laboratories. The project is designed to study and implement innovative mobile laboratories having the same dimensions as standard shipping containers. They are used in specific environmental activities and designed to be installed on board a ship, an offshore platform or used on land as a multi-activity operative base.  相似文献   

Using the pseudospectral technique on curved grids for 2D acoustic forward modelling1     

Per Nielsen  Flemming If  Per Berg  Ove Skovgaard 《Geophysical Prospecting》1994,42(4):321-341

The Fourier pseudospectral method has been widely accepted for seismic forward modelling because of its high accuracy compared to other numerical techniques. Conventionally, the modelling is performed on Cartesian grids. This means that curved interfaces are represented in a ‘staircase fashion‘causing spurious diffractions. It is the aim of this work to eliminate these non-physical diffractions by using curved grids that generally follow the interfaces. A further advantage of using curved grids is that the local grid density can be adjusted according to the velocity of the individual layers, i.e. the overall grid density is not restricted by the lowest velocity in the subsurface. This means that considerable savings in computer storage can be obtained and thus larger computational models can be handled. One of the major problems in using the curved grid approach has been the generation of a suitable grid that fits all the interfaces. However, as a new approach, we adopt techniques originally developed for computational fluid dynamics (CFD) applications. This allows us to put the curved grid technique into a general framework, enabling the grid to follow all interfaces. In principle, a separate grid is generated for each geological layer, patching the grid lines across the interfaces to obtain a globally continuous grid (the so-called multiblock strategy). The curved grid is taken to constitute a generalised curvilinear coordinate system, where each grid line corresponds to a constant value of one of the curvilinear coordinates. That means that the forward modelling equations have to be written in curvilinear coordinates, resulting in additional terms in the equations. However, the subsurface geometry is much simpler in the curvilinear space. The advantages of the curved grid technique are demonstrated for the 2D acoustic wave equation. This includes a verification of the method against an analytic reference solution for wedge diffraction and a comparison with the pseudospectral method on Cartesian grids. The results demonstrate that high accuracies are obtained with few grid points and without extra computational costs as compared with Cartesian methods.  相似文献   

Dynamic interaction of seismic activity along rising and sinking edges of plate boundaries     

Eduard Berg  George H. Sutton  Daniel A. Walker 《Tectonophysics》1977,39(4):559-578

Cumulative and differential cumulative seismic strain release of shallow earthquakes during 1964 through 1972 show significant time-delayed correlation for many of the rises and/or sinks of tectonic plate boundaries for the Atlantic, Indian and Pacific oceans. For the Pacific, time delays are almost exclusively from areas of higher to areas of lower strain release, and could imply viscous stress relaxation along or near the lithosphere—asthenosphere boundary. Seismically determined slip rates for many of the subduction zones during 1964–1972 are lower than those of the preceding part of the century by a factor of 5. The significant correlation between many rises and sinks suggests worldwide interaction and coupling of plate motion.  相似文献   

Seismic array evidence of lateral variations in the lower mantle     

D.J. Doornbos  J.M. Vermeulen  A.P. Van Den Berg  S.A.P.L. Cloetingh 《Physics of the Earth and Planetary Interiors》1979,18(1):34

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Gestalt und Veränderung der Niederschlagsgebiete Nordamerikanischer Hurrikane     

Prof. Dr. Hellmut Berg 《Pure and Applied Geophysics》1954,28(1):273-284

Zusammenfassung Für zwei nordamerikanische Hurrikane wurden aufeinanderfolgende Karten der stündlichen Niederschlagsmengen gezeichnet. Sie lassen eine Beurteilung der Entwicklung der Niederschlagsgebiete im Laufe der Entwicklung des Hurrikans zu. Nur anfangs ist das Niederschlagsgebiet annähernd kreisförmig. Sehr rasch deformiert es in der Art, daß auf der Rückseite das Regengebiet sehr rasch abbricht und auch links von der Zugrichtung keine sehr große Ausdehnung hat. Dagegen ist der Niederschlag sehr ausgedehnt nach vorn und nach rechts in der Zugrichtung gesehen. Im letzten Stadium löst sich der Niederschlag sogar vom Kern des Hurrikans ab. Eine Erklärung für diese Entwicklung wird dynamisch versucht, Einflüsse von Luftmassengegensätzen werden abgelehnt, solche des Untergrundes gering eingeschätzt. Konvergenzen, die zur Wolken-und Niederschlagsbildung führen können, entstehen einmal durch Abweichungen vom Gradientwind bei der Vertiefung des Wirbels und infolge des raschen Druckfalles vor dem wandernden Wirbelsturm, zum anderen als Strömungskonvergenzen im Einzugsgebiet. Divergenzen entstehen beim Auffüllen, ferner beim Druckanstieg hinter dem wandernden Kern und im Delta der Isobaren. Durch Ueberlagerung dieser Vorgänge lassen sich prinzipiell die Aenderungen des Niederschlagsgebietes erklären.

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Summary Maps of hourly precipitation were drawn for two hurricanes of North-America. The development of precipitation areas can be shown in the course of the development of the hurricane. The precipitation area is rather circular only in the beginning. It changes very quickly: The rain area ends suddenly on the rear; moreover it is not large on the left side of the path. But there is extended precipitation ahead and on the right side. In the last stage the precipitation area leaves the center of the hurricane. A dynamical explanation is tried; influences of different air masses are rejected; influences of the surface of the earth are supposed to be very small. Convergences which may lead to the formation of clouds or to precipitation are formed on the one hand by deviation from geostrophic wind with the deepening of the vortex and because of the falling of pressure in front of the hurricane, on the other hand by convergences of flow in the area of entrance («Einzugsgebiet»). Divergences are formed in filling up and in the rising of pressure behind the moving center and in the delta of the isobars. The changing of precipitation areas may be explained by superposition of these facts.

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Vortrag, gehalten am 24. April 1954 vor der 2. allgem. Versammlung der «Società Italiana di Geofisica e Meteorologia», Genova (23.–25. April 1954).  相似文献   

Tagung über Physik der Ionosphäre in Cambridge 6.–9. September 1954     

Hellmut Berg 《Pure and Applied Geophysics》1954,29(1):230-233

Ohne Zusammenfassung  相似文献   

Ionosphärentagung 1954 der Arbeitsgemeinschaft Ionosphäre der Deutschen Geophysikalischen Institute in Kleinheubach 28.–30. Oktober 1954     

Hellmut Berg 《Pure and Applied Geophysics》1954,29(1):234-235

Ohne Zusammenfassung  相似文献   

Kritische Bemerkungen zu denPb-Angaben bei Nahbeben     

Prof. Dr. Hellmut Berg 《Pure and Applied Geophysics》1954,28(1):66-74

Zusammenfassung Die in den «Bulletins» der Erdbebenstationen angegebenen Einsatzbezeichnung en haben zweifellos nicht die Sicherheit wie die aus einer monographischen Bearbeitung eines Bebens gewonnenen Ergebnisse. Doch sollte man annehmen, daß die Verwertung der Bulletin-Angaben als statistisches Kollektiv möglich ist. Um dies an denPb-Einsätzen zu prüfen, wurden vor allen die DifferenzenPb-Pn einer Reihe europäischer Stationen als Funktion der Epizentralentfernung der Beben und als Funktion der ZeitdifferenzSg-Pg dargestellt. Der Auswertung der EinsätzePg undSg wurde dabei von vornherein eine größere Sicherheit zugeschrieben als derjenigen derPb-Einsätze. Es ergab sich in dieser Darstellung eine sehr starke Streuung der DifferenzenPb-Pn als Funktion vonSg-Pg, die so weit geht, daß man annehmen muß, daß vielfachPg-Einsätze alsPb gedeutet wurden und umgekehrt. Auffällig ist, daß die ebenfalls als Funktion vonSg-Pg dargestellte DifferenzPg-Pn beim Fehlen einer Angabe vonPb kleiner ist als bei gleichzeitig angegebenemPb undPg. Teile von Laufzeitkurven nach den Angaben der «Bulletins» verstärken den Eindruck, daß von den einzelnen Stationen verschiedene und nicht sich entsprechende Einsätze alsPb gedeutet wurden. Es wird deshalb die Forderung erhoben, diePb-Einsätze zum Studium von Einzeluntersuchungen zu machen.

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Summary The notations of the different phases of an earthquake published in the seismic bulletins will certainly not be so reliable as the results from a monographic study of a single earthquake. Nevertheless one should suppose, that it is possible, to use these dates of the bulletins as a statistic collective. To test this opinion all the differencesPb-Pn of some european stations were plotted as a function of the epicentre distance of the seism and as a function of the differenceSg-Pg. This latter difference was supposed to be more reliable than that ofPb-Pn. In this diagram a very wide scattering of the dots (Pb-Pn againstSg-Pg) resultet, which is so suspicious, that one is obliged to suppose, that oftenPb had been interpreted instead ofPg and viceversa. It is striking, that the differencePg-Pn plotted as well againstSg-Pg is smaller, when there is no date ofPb but whenPb is published besidesPg. Parts of hodographs according to the dates of the bulletins strengthen the impression, that different and not corresponding indents have been interpreted to representPb. Therefore detailed inquirations are required, to check the detailedPb dates as published in the bulletins.

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