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31.
FerryBox - Application of continuous water quality observations along transects in the North Sea 总被引:1,自引:2,他引:1
In 2002, the Helmholtz-Zentrum Geesthacht, Germany, started to use FerryBox-automated monitoring systems on Ships of Opportunity
to continuously record standard oceanographic, biological and chemical in situ data in the North Sea. The present study summarises
the operational experience gathered since the beginning of this deployment and reflects on the potential and limits of FerryBox
systems as a monitoring tool. One part relates to the instrumental performance, constancy of shipping services, and the availability
and quality of the recorded in situ data. The other considers integration of the FerryBox observations in scientific applications
and routine monitoring campaigns. Examples are presented that highlight the added value of the recorded data for the study
of both long- and short-term variability in water mass stability, plankton communities and surface water productivity in the
North Sea. Through the assessment of technical and scientific performance, it is evident that FerryBoxes have become a valuable
tool in marine research that helps to fill gaps in coastal and open ocean operational observation networks. 相似文献
32.
Wilhelm Nümann 《Aquatic Sciences - Research Across Boundaries》1973,35(2):206-238
Statistics for all important fish for the past 60 years and the management measures taken, together with the scientific results,
have been evaluated, in order to recognize the development trend and the success or failure of the measures. Although total
yields have increased by 500%, the catches for some species i.e. pike, pike-perch and lake trout, have decreased in the past
15 years in spite of enormous measures. The possible reasons are discussed. Cannibalism and decimation through rapacious fish
regulate the yield and cause oscillations. Therefore studies on the biology of fish must rather consider the correlations
between the single species. For good management, it is more important to plant alevins than fry.
Meinem Mitarbeiter Heinz Quoss danke ich recht herzlich für die Zusammenstellung der einzelnen statistischen Werte und für die zahlreichen Berechnungen. 相似文献
Meinem Mitarbeiter Heinz Quoss danke ich recht herzlich für die Zusammenstellung der einzelnen statistischen Werte und für die zahlreichen Berechnungen. 相似文献
33.
34.
James C. Hower Jennifer M.K. O'Keefe Kevin R. Henke Amirhossein Bagherieh 《International Journal of Coal Geology》2011,88(4):227
Coal fires in natural outcrops, in abandoned and active coal mines, and in coal and coal-refuse piles are responsible for the uncontrolled emissions of gases, including CO, CO2, H2S, hydrocarbons, and volatile aromatics. Typically, measurements of gases at a mine vent are made over a short time interval, perhaps no more than 10 min, including the time for replicate measurements. Such timing provides little information on longer-term variations in emissions, although comparisons of seasonal measurements suggest such changes do occur. To address this problem, we placed temperature and CO data loggers in coal fire vents to collect time series measurements for a period of up to three weeks. For one experiment, 11 days of data at one-minute intervals indicated that the CO emissions were generally in the 400–550 ppmv range. However near daily depressions in CO concentrations occurred and in some cases fell below 50 ppmv; followed by an increase to ~ 700–800 ppmv; in turn followed by a return to the ambient conditions. Data for a separate 21-day collection period in a different vent of the same fire exhibited similar trends, albeit at a higher CO concentration. The drop in CO concentration may be associated with a meteorologically-driven inhalation cycle of the fire, whereby air diluted the combustion generated CO. We propose this was followed by an increase in the intensity of the fire due to increased O2 from the inhaled air, producing increased CO concentrations, before settling back to the ambient conditions. 相似文献
35.
Wilhelm Bierther 《International Journal of Earth Sciences》1948,35(2):106-115
Ohne Zusammenfassung 相似文献
36.
W. Salomon Wilckens Steinmann Wilhelm Salomon Donath 《International Journal of Earth Sciences》1928,19(5):425-432
Ohne Zusammenfassung 相似文献
37.
B. Wilhelm F. Arnaud P. Sabatier O. Magand E. Chapron T. Courp K. Tachikawa B. Fanget E. Malet C. Pignol E. Bard J. J. Delannoy 《第四纪科学杂志》2013,28(2):189-199
A high‐resolution sedimentological and geochemical study of a high‐altitude proglacial lake (Lake Blanc, Aiguilles Rouges, 2352 m a.s.l.) revealed 195 turbidites, 190 of which are related to flood events over the last 1400 years. We used the coarsest sediment fraction of each turbidite as a proxy for the intensity of each flood event. Because most flood events at this locality are triggered by localized summer convective precipitation events, the reconstructed sedimentary record reveals changes in the frequency and intensity of such events over the last millennium. Comparisons with other temperature, palaeohydrological and glacier reconstructions in the region suggest that the most intense events occurred during the warmest periods, i.e. during the Medieval Climate Anomaly (AD 800–1300) and the current period of global warming. On a multi‐decadal time scale, almost all the flood frequency peaks seem to correspond to warmer periods, whereas multi‐centennial variations in flood frequency appear to follow the regional precipitation pattern. Consequently, this new Alpine flood record provides further evidence of a link between climate warming and an increase in the frequency and intensity of flooding on a multi‐decadal time scale, whereas the centennial variability in flood frequencies is related to regional precipitation patterns. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
38.
Geochemical exploration for platinum-group elements in the Bushveld Complex, South Africa 总被引:2,自引:0,他引:2
H. J. Wilhelm H. Zhang F. L. Chen J. H. Elsenbroek M. Lombard D. de Bruin 《Mineralium Deposita》1997,32(4):349-361
Analyses of stream sediment and soil samples from the Bushveld Complex, South Africa have revealed enhanced precious metal
concentrations, which can be related both to mining activities and the presence of hidden concentrations of platinum-group
elements (PGEs) and gold. The economically important PGE deposits hosted by the Upper Critical Zone of the Rustenburg Layered
Suite are revealed by a high PGE and Au content in the overlying soils. A second zone of elevated precious metal concentrations
straddles the boundary between the Main and Upper Zones and has to date been traced for more than 100 km. This zone follows
the igneous layering of the Rustenburg Layered Suite and is offset by the Brits Graben. It is therefore thought to be the
reflection of a magmatic PGE-Au mineralisation.
Received: 31 May 1996 / Accepted: 7 January 1997 相似文献
39.
A humic acid extracted from a peat was easily hydrolysed by 6N HCl after oxidation with peracetic acid. The proportion of amino-acids in the hydrolysate was high (11,7 g of aminoacids per 100 g of humic acid), when the proportion of NH3 was relatively low. 17 aminoacids were identified and titrated. On the opposite, a humic acid with the same origin, which was not oxidised with peracetic acid, gave less amino-acids on hydrolysis, but tenfold more NH3, which is probably produced by partial decomposition of the amino-acids. 相似文献
40.
K. Wilhelm 《Astronomische Nachrichten》2010,331(5):502-511
Quantitative solar spectroscopy must be based on calibrated instrumentation. The basic requirement of a calibration, i.e., a comparison between the instrument under test and a primary laboratory standard through appropriate procedures, will be briefly reviewed, and the application to modern space instruments will be illustrated. Quantitative measurements of spectral radiances with high spectral and spatial resolutions as well as spectral irradiances yield detailed information on temperatures, electron densities, bulk and turbulent motions, element abundances of plasma structures in various regions of the solar atmosphere – from the photosphere to the outer corona and the solar wind. The particular requirements for helioseismology and magnetic‐field observations will not be covered in any depth in this review. Calibration by a laboratory standard is necessary, but not sufficient, because an adequate radiometric stability can only be achieved together with a stringent cleanliness concept that rules out a contamination of the optical system and the detectors as much as possible. In addition, there is a need for calibration monitoring through inter‐calibration and other means (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献