New Spectroscopic Data of 17 Coplanar Polychlorinated Terphenyls Known as Scarcely Investigated Environmental Pollutants          下载免费PDF全文

Katharina Schäfer  Hubertus Wichmann  Frank Surup  Müfit Bahadir 《洁净——土壤、空气、水》2018,46(9)

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Effects of atmospheric stability conditions on heat fluxes from small water surfaces in (semi-)arid regions     

Ali Abbasi  Frank Ohene Annor  Nick van de Giesen 《水文科学杂志》2017,62(9):1422-1439

Atmospheric stability conditions over the water surface can affect the evaporative and convective heat fluxes from the water surface. Atmospheric instability occurred 72.5% of the time and resulted in 44.7 and 89.2% increases in the average and maximum estimated evaporation, respectively, when compared to the neutral condition for a small shallow lake (Binaba) in Ghana. The proposed approach is based on the bulk-aerodynamic transfer method and the Monin-Obukhov similarity theory (MOST) using standard meteorological parameters measured over the surrounding land. For water surface temperature, a crucial parameter in heat flux estimation from water surfaces, an applicable method is proposed. This method was used to compute heat fluxes and compare them with observed heat fluxes. The heat flux model was validated using sensible heat fluxes measured with a 3-D sonic anemometer. The results show that an unstable atmospheric condition has a significant effect in enhancing evaporation alongside the sensible heat flux from water surfaces.  相似文献   

Overview of tritium records from precipitation and surface waters in Germany     

Axel Schmidt  Gabriele Frank  Willibald Stichler  Lars Duester  Thomas Steinkopff  Christine Stumpp 《水文研究》2020,34(6):1489-1493

Tritium is one of the most important environmental tracers in isotope hydrology for understanding the dynamics of groundwater and connected surface water and has been used in a wide range of applications at different scales. A key requirement for using tritium as a tracer is the knowledge of its spatial and temporal distribution in different water types. As a fundamental input, quantity long-term time series of tritium in precipitation are of particular importance. In this paper, the authors present an overview of tritium data sets of the Federal Institute of Hydrology (BfG), the Helmholtz Zentrum München (HMGU) and the German Weather Service (DWD). Since the 1970s, all three institutions have monitored the tritium concentration at 53 surface water and 37 precipitation stations on a monthly basis. The primary purpose of the data set was to provide baseline information for different water types all over Germany as an integral part of the German radiation protection monitoring system. Additionally, as geochemically inert tracer, tritium provides a unique tool to different user groups in a wide range of research questions and applications.  相似文献   

Rapid visual screening of soft-story buildings from street view images using deep learning classification     

Yu  Qian  Wang  Chaofeng  McKenna  Frank  Yu  Stella X.  Taciroglu  Ertugrul  Cetiner  Barbaros  Law  Kincho H. 《地震工程与工程振动(英文版)》2020,19(4):827-838

Rapid and accurate identification of potential structural deficiencies is a crucial task in evaluating seismic vulnerability of large building inventories in a region. In the case of multi-story structures, abrupt vertical variations of story stiffness are known to significantly increase the likelihood of collapse during moderate or severe earthquakes. Identifying and retrofitting buildings with such irregularities—generally termed as soft-story buildings—is, therefore, vital in earthquake preparedness and loss mitigation efforts. Soft-story building identification through conventional means is a labor-intensive and time-consuming process. In this study, an automated procedure was devised based on deep learning techniques for identifying soft-story buildings from street-view images at a regional scale. A database containing a large number of building images and a semi-automated image labeling approach that effectively annotates new database entries was developed for developing the deep learning model. Extensive computational experiments were carried out to examine the effectiveness of the proposed procedure, and to gain insights into automated soft-story building identification.

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Historical seismogram reproductions for the source parameters determination of the 1902, Atushi (Kashgar) earthquake     

Galina Kulikova  Frank Krüger 《Journal of Seismology》2017,21(6):1577-1597

The majority of original seismograms recorded at the very beginning of instrumental seismology (the early 1900s) did not survive till present. However, a number of books, bulletins, and catalogs were published including the seismogram reproductions of some, particularly interesting earthquakes. In case these reproductions contain the time and amplitude scales, they can be successfully analyzed the same way as the original records. Information about the Atushi (Kashgar) earthquake, which occurred on August 22, 1902, is very limited. We could not find any original seismograms for this earthquake, but 12 seismograms from 6 seismic stations were printed as example records in different books. These data in combination with macroseismic observations and different bulletins information published for this earthquake were used to determine the source parameters of the earthquake. The earthquake epicenter was relocated at 39.87° N and 76.42° E with the hypocenter depth of about 18 km. We could further determine magnitudes m _B = 7.7 ± 0.3, M _S = 7.8 ± 0.4, M _W = 7.7 ± 0.3 and the focal mechanism of the earthquake with strike/dip/rake ? 260°± 20/30°± 10/90°± 10. This study confirms that the earthquake likely had a smaller magnitude than previously reported (M8.3). The focal mechanism indicates dominant thrust faulting, which is in a good agreement with presumably responsible Tuotegongbaizi-Aerpaleike northward dipping thrust fault kinematic, described in previous studies.  相似文献   

Short-term climate changes during the Last Glacial–Holocene transition: comparison between Mediterranean records and the GRIP event stratigraphy     

A. Asioli  F. Trincardi  J. J. Lowe  F. Oldfield 《第四纪科学杂志》1999,14(4):373-381

This paper presents biostratigraphical and stable isotope data obtained from core CM92–43, which was recovered from the central Adriatic as part of a comprehensive investigation of the palaeoenvironmental history of the basin. The data span the period of the Last Glacial–Holocene (LG–H) transition (ca. 18000 to 8000 GRIP ice-core yr BP). Regional biozones are defined on the basis of characteristic assemblages of planktic Foraminifera, and these are compared with other foraminiferal biostratigraphical schemes from the southern Adriatic and the Tyrrhenian Sea. Variations in relative abundance of selected planktic Foraminifera and in selected pollen types are shown alongside variations in δ¹⁸O and δ¹³C obtained from Globigerina bulloides and relative abundance of Globigerinoides ex. gr. ruber. The data are compared with the GRIP ice-core record and the event stratigraphy scheme based on this record, and it is concluded that the climate forcing mechanisms that controlled climate variations in the North Atlantic region during the LG–H transition also extended their influence into the Mediterranean region over the same period. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

The axial angular momentum balance of a global ocean general circulation model     

Frank O. Bryan 《Dynamics of Atmospheres and Oceans》1997,25(3):191-216

In this study we examine the axial angular momentum balance of a non-eddy-resolving global ocean general circulation model, from the perspective of the geographical and seasonal variability of angular momentum and from the perspective of the torques acting on the ocean through its surfaces. Our purpose is to provide an estimate of the magnitude of the seasonal storage of angular momentum in the ocean and hence the oceanic excitation of variability in length of day, and to elucidate the role of the ocean in transferring angular momentum between the atmosphere and the Earth's crust. We provide an assessment of the reliability of the model results by examining the sensitivity of the angular momentum and torque distributions to several model parameters.Although the Southern Ocean region containing the Antarctic Circumpolar Current (ACC) makes the largest contribution to both the annual mean oceanic angular momentum and its seasonal variability, inclusion of the rest of the world ocean reduces both of these quantities to about two-thirds of the value of the Southern Ocean alone. The annual, global mean angular momentum is found to be insensitive to most model choices except for the isopycnal diffusivity. The seasonal variability, on the other hand, is insensitive to the isopycnal diffusivity, but sensitive to the smoothness of the representation of topography and moderately sensitive to horizontal and vertical friction parameterizations. The torque balance at all latitudes, including within the Antarctic circumpolar belt, is between wind stress and bottom pressure torques. Horizontal friction torques are small but non-negligible. Bottom friction and storage of angular momentum are negligible in angular momentum budgets on seasonal time scales. Two commonly used wind stress climatologies, one based on historical marine meteorological observations and the other based on operational weather analyses, differ in the sign of the globally integrated wind stress torque.  相似文献   

Spatial dependency of cholera prevalence on potential cholera reservoirs in an urban area,Kumasi, Ghana     

Frank B. Osei  Alfred A. Duker  Ellen-Wien Augustijn  Alfred Stein 《International Journal of Applied Earth Observation and Geoinformation》2010

Cholera has been a public health burden in Ghana since the early 1970s. Between 1999 and 2005, a total of 25,636 cases and 620 deaths were officially reported to the WHO. In one of the worst affected urban cities, fecal contamination of surface water is extremely high, and the disease is reported to be prevalent among inhabitants living in close proximity to surface water bodies. Surface runoff from dump sites is a major source of fecal and bacterial contamination of rivers and streams in the study area. This study aims to determine (a) the impacts of surface water contamination on cholera infection and (b) detect and map arbitrary shaped clusters of cholera. A Geographic Information System (GIS) based spatial analysis is used to delineate potential reservoirs of the cholera vibrios; possibly contaminated by surface runoff from open space refuse dumps. Statistical modeling using OLS model reveals a significant negative association between (a) cholera prevalence and proximity to all the potential cholera reservoirs (R² = 0.18, p < 0.001) and (b) cholera prevalence and proximity to upstream potential cholera reservoirs (R² = 0.25, p < 0.001). The inclusion of spatial autoregressive coefficients in the OLS model reveals the dependency of the spatial distribution of cholera prevalence on the spatial neighbors of the communities. A flexible scan statistic identifies a most likely cluster with a higher relative risk (RR = 2.04, p < 0.01) compared with the cluster detected by circular scan statistic (RR = 1.60, p < 0.01). We conclude that surface water pollution through runoff from waste dump sites play a significant role in cholera infection.  相似文献   

Origin of blocky aragonite cement in Cenozoic glaciomarine sediments,McMurdo Sound,Antarctica     

Mingyu Yang  Tracy D. Frank  Christopher R. Fielding  Megan E. Smith  Peter K. Swart 《Sedimentology》2020,67(2):721-741

Inorganic aragonite occurs in a wide spectrum of depositional environments and its precipitation is controlled by complex physio-chemical factors. This study investigates diagenetic conditions that led to aragonite cement precipitation in Cenozoic glaciomarine deposits of McMurdo Sound, Antarctica. A total of 42 sandstones that host intergranular cement were collected from the CIROS-1 core, located proximal to the terminus of Ferrar Glacier. Standard petrography, Raman spectroscopy and electron microprobe analysis reveal a prominent aragonite cement phase that occurs as a pore-filling blocky fabric throughout the core. Oxygen isotope compositions (δ¹⁸O = −30·0 to −8·6‰ Vienna Pee-Dee Belemnite) and clumped isotope temperatures (TΔ₄₇ = 13·1 to 31·5°C) determined from the aragonite cements provide precise constraints on isotopic compositions (δ¹⁸O_w) of the parent fluid, which mostly range from −10·8 to −7·2‰ Vienna Standard Mean Ocean Water. The fluid δ¹⁸O_w values are consistent with those of pore water, previously identified as cryogenic brine in the nearby AND-2A core. Petrographic and geochemical data suggest that aragonite cement in the CIROS-1 core precipitated from a similar brine. The brine likely formed and infiltrated sediments in flooded glacial valleys along the western margin of McMurdo Sound during the middle Miocene Climatic Transition, and subsequently flowed basinward in the subsurface. Consequently, the brine forms as a longstanding subsurface fluid that has saturated Cenozoic sediments below southern McMurdo Sound since at least the middle Miocene. Aragonite cementation in the CIROS-1 core is interpreted to reflect its proximal position to sites of brine formation and greater likelihood of experiencing brines with sustained high carbonate saturation states and Mg/Ca ratios. This unusual occurrence expands the range of known natural occurrences of aragonite cement. Given the potential for cryogenic brine formation in glaciomarine settings, blocky aragonite, as the end member of the spectrum of aragonite cement morphology, may be more widespread in glaciomarine sediments than currently thought.  相似文献   

Interhemispheric synchrony of Late-glacial climatic instability as recorded in proglacial Lake Mascardi,Argentina     

Daniel Ariztegui  María Martha Bianchi  Julieta Masaferro  Eric Lafargue  Frank Niessen 《第四纪科学杂志》1997,12(4):333-338

Several high-resolution continental records have been reported recently in sites in South America, but the extent to which climatic variations were synchronous between the northern and southern hemispheres during the Late-glacial–Holocene transition, and the causes of the climatic changes, remain open questions. Previous investigations indicated that, east of the Andes, the middle and high latitudes of South America warmed uniformly and rapidly from 13 000 ¹⁴C yr BP, with no indication of subsequent climate fluctuations, equivalent, for example, to the Younger Dryas cooling. Here we present a multiproxy continuous record, radiocarbon dated by accelerated mass spectroscopy, from proglacial Lake Mascardi in Argentina. The results show that unstable climatic conditions, comparable to those described from records obtained in the Northern Hemisphere, dominated the Late-glacial–Holocene transition in Argentina at this latitude. Furthermore, a significant advance of the Tronador ice-cap, which feeds Lake Mascardi, occurred during the Younger Dryas Chronozone. This instability suggests a step-wise climatic history reflecting a global, rather than regional, forcing mechanism. The Lake Mascardi record, therefore, provides strong support for the hypothesis that ocean–atmosphere interaction, rather than global ocean circulation alone, governed interhemispheric climate teleconnections during the last deglaciation. © 1997 John Wiley & Sons, Ltd.  相似文献