Beiträge zur Hydrographie und Wärmebilanz der Nordsee     

Dr. Gerd Axel Becker 《Ocean Dynamics》1981,34(5):167-262

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Persistent organic pollutants in rough-toothed dolphins (Steno bredanensis) sampled during an unusual mass stranding event   总被引：1，自引：0，他引：1  

Struntz WD  Kucklick JR  Schantz MM  Becker PR  McFee WE  Stolen MK 《Marine pollution bulletin》2004,48(1-2):164-173

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Enhancement of aquifer vulnerability indexing using the analytic-element method     

K.?C.?FredrickEmail author  M.?W.?Becker  D.?M.?Flewelling  W.?Silavisesrith  E.?R.?Hart 《Environmental Geology》2004,45(8):1054-1061

Indexing methods are used for the evaluation of aquifer vulnerability and establishing guidelines for the protection of ground-water resources. The principle of the indexing method is to rank influences on groundwater to determine overall vulnerability of an aquifer to contamination. The analytic element method (AEM) of ground-water flow modeling is used to enhance indexing methods by rapidly calculating a potentiometric surface based primarily on surface-water features. This potentiometric map is combined with a digital-elevation model to produce a map of water-table depth. This is an improvement over simple water-table interpolation methods. It is physically based, properly representing surface-water features, hydraulic boundaries, and changes in hydraulic conductivity. The AEM software, SPLIT, is used to improve an aquifer vulnerability assessment for a valley-fill aquifer in western New York State. A GIS-based graphical user interface allows automated conversion of hydrography vector data into analytic elements.  相似文献   

Determination of HBCD, PBDEs and MeO-BDEs in California sea lions (Zalophus californianus) stranded between 1993 and 2003   总被引：1，自引：0，他引：1  

Stapleton HM  Dodder NG  Kucklick JR  Reddy CM  Schantz MM  Becker PR  Gulland F  Porter BJ  Wise SA 《Marine pollution bulletin》2006,52(5):522-531

Blubber samples from male California sea lions (Zalphophus californianus) stranded between 1993 and 2003 were analyzed for 27 polybrominated diphenyl ether (PBDE) congeners, three isomers of hexabromocyclododecane (HBCD) and 14 methoxylated polybrominated diphenyl ether (MeO-BDE) congeners. Total PBDEs ranged from 450 ng/g to 4740 ng/g wet mass and total HBCD ranged from < 0.3 ng/g to 12 ng/g wet mass. The concentration of HBCD increased from 0.7 ng/g to12.0 ng/g wet mass in sea lion blubber between 1993 and 2003. However, no significant temporal trend was observed for any of the other brominated compounds over this 10 year period. Only one of the 14 MeO-BDE congeners was detected in the blubber samples, 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE 47), and concentrations ranged from < 0.2 ng/g to 12 ng/g wet mass. A bromo-, chloro-heterocyclic compound, 1,1'-dimethyl-tetrabromo-dichloro-2,2'-bipyrrole (DBP-Br4Cl2), previously reported in marine species along the Pacific coast, was also identified in the sea lion blubber. DBP-Br4Cl2 ranged from 44 ng/g wet mass to 660 ng/g wet mass and was present at concentrations rivaling the dominant PBDE congener, BDE 47 (2,2',4,4'-tetrabromodiphenyl ether). Concentrations of DBP-Br4Cl2 were positively correlated with 6-MeO-BDE 47 (r = 0.7; p < 0.05). Both of these compounds have been identified in marine algae and sponges, and studies suggest they are both produced from natural sources. This study demonstrates that brominated compounds from both anthropogenic and biogenic sources can accumulate to similar levels in marine mammals. In addition, HBCD concentrations appear to be increasing in California sea lion populations, whereas PBDE concentrations, between 1993 and 2003, were highly variable.  相似文献   

The ‘throwntogetherness’ of research: Reflections on conducting fieldwork in South Africa     

Alistair Fraser 《Singapore journal of tropical geography》2012,33(3):291-295

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Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000?years     

Matthew J. Wooller  John W. Pohlman  Benjamin V. Gaglioti  Peter Langdon  Miriam Jones  Katey M. Walter Anthony  Kevin W. Becker  Kai-Uwe Hinrichs  Marcus Elvert 《Journal of Paleolimnology》2012,48(1):27-42

Atmospheric contributions of methane from Arctic wetlands during the Holocene are dynamic and linked to climate oscillations. However, long-term records linking climate variability to methane availability in Arctic wetlands are lacking. We present a multi-proxy ~12,000?year paleoecological reconstruction of intermittent methane availability from a radiocarbon-dated sediment core (LQ-West) taken from a shallow tundra lake (Qalluuraq Lake) in Arctic Alaska. Specifically, stable carbon isotopic values of photosynthetic biomarkers and methane are utilized to estimate the proportional contribution of methane-derived carbon to lake-sediment-preserved benthic (chironomids) and pelagic (cladocerans) components over the last ~12,000?years. These results were compared to temperature, hydrologic, and habitat reconstructions from the same site using chironomid assemblage data, oxygen isotopes of chironomid head capsules, and radiocarbon ages of plant macrofossils. Cladoceran ephippia from ~4,000?cal?year BP sediments have ??¹³C values that range from ~?39 to ?31??, suggesting peak methane carbon assimilation at that time. These low ??¹³C values coincide with an apparent decrease in effective moisture and development of a wetland that included Sphagnum subsecundum. Incorporation of methane-derived carbon by chironomids and cladocerans decreased from ~2,500 to 1,500?cal?year BP, coinciding with a temperature decrease. Live-collected chironomids with a radiocarbon age of 1,640?cal?year BP, and fossil chironomids from 1,500?cal?year BP in the core illustrate that ??old?? carbon has also contributed to the development of the aquatic ecosystem since ~1,500?cal?year BP. The relatively low ??¹³C values of aquatic invertebrates (as low as ?40.5??) provide evidence of methane incorporation by lake invertebrates, and suggest intermittent climate-linked methane release from the lake throughout the Holocene.  相似文献   

Projection of economic impacts of climate change in sectors of Europe based on bottom up analysis: human health     

Paul Watkiss  Alistair Hunt 《Climatic change》2012,112(1):101-126

This paper scopes a number of the health impacts of climate change in Europe (EU-27) quantitatively, using physical and monetary metrics. Temperature-related mortality effects, salmonellosis and coastal flooding-induced mental health impacts resulting from climate change are isolated from the effects of socio-economic change for the 2011–2040 and 2071–2100 time periods. The temperature-induced mortality effects of climate change include both positive and negative effects, for winter (cold) and summer (heat) effects, respectively, and have welfare costs (and benefits) of up to 100 billion Euro annually by the later time-period, though these are unevenly distributed across countries. The role of uncertainty in quantifying these effects is explored through sensitivity analysis on key parameters. This investigates climate model output, climate scenario, impact function, the existence and extent of acclimatisation, and the choice of physical and monetary metrics. While all of these lead to major differences in reported results, acclimatisation is particularly important in determining the size of the health impacts, and could influence the scale and form of public adaptation at the EU and national level. The welfare costs for salmonellosis from climate change are estimated at potentially several hundred million Euro annually by the period 2071–2100. Finally, a scoping assessment of the health costs of climate change from coastal flooding, focusing on mental health problems such as depression, are estimated at up to 1.5 billion Euro annually by the period 2071–2100.  相似文献   

Identification of mid-latitudinal regional and urban temperature variabilities based on regional reanalysis data     

Woonsup Choi  Anke Keuser  Stefan Becker 《Theoretical and Applied Climatology》2012,107(1-2):87-98

The objective of the study is to detect geographical and temporal variations of near surface air temperatures over Minnesota and Wisconsin, USA derived from the North American Regional Reanalysis (NARR) dataset. In addition, the study serves to assess the usefulness of NARR temperature data to analyze regional and local temperature variations. Particular emphasis was placed on the analyses on the temperature-modifying effects of the Great Lakes and large urban environments. We analyzed annual mean, daily maximum and minimum, and January minimum and July maximum temperatures for the period 1979–2006 by using methods such as ordinary kriging, principal component analysis, and the Mann–Kendall test. On a regional scale, we found significant effects of the latitude and the Great Lakes on the spatial variability of the data. Furthermore, we found clearly identifiable effects of large urban areas in the study region (Minneapolis—Saint Paul and Milwaukee), which are more evident in the principal component scores than in the temperature data themselves. While we failed to detect significant July maximum temperature trends, we detected significantly increasing trends in January minimum and mean annual temperature datasets in the eastern part of the region. Overall, the present study has demonstrated the potential of using NARR data for urban climate research.  相似文献   

Quasi periodicities of extreme precipitation events in the Yangtze River basin, China   总被引：1，自引：0，他引：1  

S. Becker  H. Hartmann  M. Coulibaly  Q. Zhang  T. Jiang 《Theoretical and Applied Climatology》2008,94(3-4):139-152

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Solar System Observations with MIRI, The Mid InfraRed Instrument on the James Webb Space Telescope     

John K. Davies  Gillian S. Wright  Alistair C. H. Glasse 《Earth, Moon, and Planets》2009,105(2-4):73-80

MIRI is the Mid InfraRed Instrument for the James Webb Space Telescope (JWST) and will provide imaging, coronography and integral field spectroscopy in the range between 4.9 and 28.6  $\upmu \hbox{m}.$ We summarise solar system observations which may be possible with this instrument, drawing on examples of observations made with previous space missions such as IRAS, ISO and Spitzer.  相似文献