Geochemistry of a piston core from Ontong Java Plateau (western equatorial Pacific): evidence for sediment redistribution and changes in paleoproductivity     

B. Schwarz  A. Mangini  M. Segl 《International Journal of Earth Sciences》1996,85(3):536-545

We discuss geochemical proxies, reflecting processes of primary productivity, CaCO₃ dissolution, and sediment redistribution in a piston core (RNDB 74P) from the Ontong Java Plateau. Due to the shallow water depth, biogenic carbonate is well preserved and a very goodδ ¹⁸O stratigraphy is available down to isotopic stage 11.²³⁰Th_ex gives evidence that the sediment accumulation pattern is driven mainly by processes of sediment focusing or winnowing. Due to the constant production of²³⁰Th in the water column, the bulk sediment accumulation rates could be corrected for the particle rain deriving from the water column above. The²³⁰Th_ex ⁰/CaCO₃ ratio reflects the well-known Pacific CaCO₃ preservation pattern with ice growth dissolution spikes and deglacial preservation spikes. The record of the grain size fraction >63 μm supports these results. The downcore concentrations and accumulation rates of barium (Ba) are on a higher level during interglacials and show several peaks. Normalization of Ba with²³⁰Th_ex ⁰ delivers a more uniform level of the Ba accumulation rates throughout the core. This pattern suggests a constantly higher biological productivity (nearly tenfold) in this area throughout the past 200 kyr compared with an open ocean environment. Barium peaks observed at the climatic transitions 2/1 and 6/5 and in stage 5 are in contrast to a predicted reduction of interglacial productivity at this location. A possible explanation might be the onset of the modern circulation pattern. The transition from Ba-enriched deep water to lower contents in the Atlantic might have resulted in an enhanced deposition of Ba in the Pacific.  相似文献   

Verfahren zur Verhinderung von Verockerungserscheinungen an Steigleitungen,Filterbrunnen, Brunnenelementen und anderen wasserführenden Objekten. Teil 3: Einsatzmöglichkeiten und Ergebnisse an Praxisanlagen     

R. Fischer  H. Reissig  J. Bach  U. Sauer  H. Schwarz  K.-O. Gottschalk  S. Petrich 《洁净——土壤、空气、水》1991,19(1):97-102

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A consistency test of airborne GPS using multiple monitor stations   总被引：2，自引：1，他引：2  

M. E. Cannon  K. P. Schwarz  M. Wei  D. Delikaraoglou 《Journal of Geodesy》1992,66(1):2-11

In October 1990, several airborne GPS tests were conducted in the Ottawa region by the Canada Centre for Surveying (CCS) and the Canada Centre for Remote Sensing (CCRS). Ashtech XII receivers were located at up to three monitor stations with baseline lengths to the aircraft ranging from 1–200 km. Approximately two hours of airborne data, collected at a 2 Hz rate, were available for each of the three test days. Post-processing of the differential data was done using the University of Calgary's SEMIKIN package which utilizes a Kalman filter algorithm to estimate both the remote receiver's position and velocity. Comparisons were made between the aircraft position and velocity determined from each of the monitor stations to assess the consistency of differential GPS when different reference stations are used. Results show that the degree of consistency is dependent upon the distance to the monitor stations. Agreement at the decimetre-level is achieved in position when the baseline lengths are within 100 km. Agreement in velocity is usually better than 1 cm s^–1 (RMS).  相似文献   

Biomasseuntersuchungen am Zooplankton der ostmecklenburgischen Küstengewässer - ein Beitrag zum Eutrophiestatus Teil 5: Zur Biomasse des Kleinen Jasmunder Bodden     

S. Schwarz 《洁净——土壤、空气、水》1978,6(4):353-356

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Biomasseuntersuchungen am Zooplankton der ostmecklenburgischen Küstengewässer - ein Beitrag zum Eutrophiestatus. Teil 6: Zur Biomasse des Strelasundes (Hafen Stralsund)     

S. Schwarz 《洁净——土壤、空气、水》1978,6(4):357-359

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Biomasseuntersuchungen am Zooplankton der ostmecklenburgischen Küstengewässer — ein Beitrag zum Eutrophiestatus Teil 2: Hydrographische Untersuchungen im Küstenbereich nördlich Hiddensee     

S. Schwarz 《洁净——土壤、空气、水》1977,5(5):465-472

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Local characteristics of the gravity anomaly covariance function     

K. P. Schwarz  G. Lachapelle 《Journal of Geodesy》1980,54(1):21-36

Summary Using a data set of 260 000 gravity anomalies it is shown that common characteristics for a local covariance function exist in an area as large as Canada excluding the Rocky Mountains. After eliminating global features by referencing the data to the GEM-10 satellite solution, the shape of the covariance function is remarkably consistent from one sample area to the next. The determination of the essential parameters and the fitting of the covariance function are discussed in detail. To test the reliability of the derived function, deflections of the vertical are estimated at about 230 stations where astrogeodetic data are available. Results show that the standard error obtained from the discrepancies is about1″ for each component and that the error covariance matrix of least-squares collocation reflects this accuracy remarkably well.  相似文献   

Least squares collocation and regularization     

R. Rummel  K. -P. Schwarz  M. Gerstl 《Journal of Geodesy》1979,53(4):343-361

Certain geodetic problems such as the downward continuation of gravity information from satellite or aerial altitudes to the surface of the earth or the inverse Stokes problem are improperly posed in the sense that the best approximate solution does not continuously depend on the given observations. In order to obtain a stable solution a technique of regularization is discussed which can be shown to be identical to the method of least squares collocation. The characteristic features of regularization are analysed transferring the problem through a singular value decomposition into the spectral domain which allows an easy interpretation as a special method of filtering. In practical applications the stability depends not only on the observational errors including the computer round-off but in the same way on the number of observations and their distribution. The regularized solution should achieve a proper trade-off between sufficient smoothness and highest possible resolution with a limit defined through the internal accuracy of the computer.  相似文献   

Biomasseuntersuchungen am Zooplankton der ostmecklenburgischen Küstengewässer - ein Beitrag zum Eutrophiestatus Teil 1: Zur Biomasse und Hydrodynamik der Darßer Boddenkette     

S. Schwarz 《洁净——土壤、空气、水》1975,3(3):227-237

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Sea level fluctuation during the past 6000 yr at the coast of Mauritania     

G. Einsele  D. Herm  H.U. Schwarz 《Quaternary Research》1974,4(3):282-289

In an area regarded to be very favorable for the study of Holocene sea level changes one or several eustatic (?) oscillations of sea have been found using sedimentological and ecological methods. After a maximum of +3 m during the Nouakchottian stage (= Middle Flandrian or Late Atlantic) about 5500 YBP a drop of sea to ?3.5 ± 0.5 m about 4100 YBP is testified by stromatolitic algae indicating the former sea level within the tidal zone with high accuracy. This evidence is supported by the observation of post-Nouakchottian regressive and transgressive geologic sequences, by buried beach deposits and flooded hardgrounds, post-Nouakchottian marine terraces of different height and age, the cutting off of one large and several small bays from the open sea, etc. Possibly one or two smaller oscillations followed between 4000 and 1500 YBP (derived sea level curve Fig. 3).  相似文献