Camouflaged Galactic cosmic microwave background polarization foregrounds: total and polarized contributions of the kinetic Sunyaev–Zeldovich effect     

André Waelkens  Matteo Maturi  Torsten Enßlin 《Monthly notices of the Royal Astronomical Society》2008,383(4):1425-1430

We consider the role of the Galactic kinetic Sunyaev–Zeldovich (SZ) effect as a cosmic microwave background (CMB) polarization foreground. While the Galactic thermal SZ effect has previously been studied and discarded as a potential CMB foreground, we find that the kinetic SZ effect is dominant in the Galactic case. We analyse the detectability of the kinetic SZ effect by means of an optimally matched filter technique applied to a simulation of an ideal observation. We obtain no detection, getting a signal-to-noise ratio of 0.1, thereby demonstrating that the kinetic SZ effect can also safely be ignored as a CMB foreground. However, we provide maps of the expected signal for inclusion in future high-precision data processing. Furthermore, we rule out the significant contamination of the polarized CMB signal by second scattering of Galactic kinetic SZ photons, since we show that the scattering of the CMB quadrupole photons by Galactic electrons is a stronger effect than the SZ second scattering, and has already been shown to produce no significant polarized contamination.  相似文献   

Determination of flow exits in the Soultz borehole GPK2 by using the brine displacement method     

Reinhard Jung  Marion Schindler  Patrick Nami  Torsten Tischner 《Comptes Rendus Geoscience》2010,342(7-8):636-643

The article presents a method to derive synthetic flow logs from low rate injection tests in wells, which are otherwise not accessible for logging. The tests were carried out in the 5 km deep geothermal well GPK2 in the Enhanced Geothermal System (EGS) project of Soultz-sous-Forêts (France) and were aimed at characterizing the status of the well before chemical treatments. The method consists of injecting water at constant flow rates into the well initially filled with brine. The wellhead pressure record of this test is transformed into log of the flow velocity versus depth by a technique described in the paper. Applying this method to borehole GPK2, three outlets could be detected and quantified within the cased and uncased section of this borehole. The outlet in the cased section at 3860 m absorbed 15% of the total flow. This depth corresponds to a known casing restriction, which makes the borehole inaccessible for logging operations. The two other outlets are at the casing shoe at 4420 m (15%) and at 4670 m (70%).  相似文献   

有机组分土-水分配系数的确定(英文)     

Erping BI　 Torsten SCHMIDT 《地学前缘》2005,12(Z1):199-208

有机组分的土水分配系数(Kd)是描述有机组分在地下系统中吸附特征的重要参数。同时,它也是物质运移模拟和环境评价中的主要参数之一。影响Kd的因素可概括为三个方面:土壤性质、有机组分本身特征及水相的物理化学性质。一般而言,对于非极性和弱极性有机组分,土壤中的有机质含量(foc )是影响Kd的最主要因素。但是,对于极性有机组分(POCs), 特别是在土壤有机质含量较低的情况下,土壤中矿物的种类和含量、水化学组分特征(pH、离子力等)经常在吸附过程中起重要作用。实验室内测定Kd的方法包括批实验和柱实验方法。批实验法适用于研究Kd较高情况下的吸附。在Kd较低的情况下,如低有机质土壤对极性有机污染物的吸附,土柱色谱法(SCC)是更适宜的选择。另外,可用土柱色谱法快速了解各种因素对吸附过程的影响,并获取详细的吸附和解吸信息。应用土柱色谱法时应当注意非平衡吸附和可能的柱堵塞问题。很多文献中提到结合柱实验和已有的吸附数据来预测土壤有机碳标准化的分配系数Koc(=Kd/foc)。但是,如果没有考虑吸附中特定的作用过程(如矿物吸附),对极性有机组分Koc的预测将会产生很大的误差。在环境评价中,将从一种土壤测定的Koc 应用到不同性质的土壤中,可能会导致错误的认识。在进行室内实验时,应把标准土(如Eurosoi  相似文献   

Discharge and transport processes along the German Baltic Sea Coast     

Herbert Siegel  Torsten Seifert  Gerald Schernewski  Monika Gerth  Thomas Ohde  Jan Reißmann  Victor Podsetchine 《Ocean Dynamics》2005,55(1):47-66

The western Baltic Sea infront of the German coast is a highly variable dynamical system, dominated by a complex and small-scale morphometry, the water exchange between the Baltic and North Seas, and driven by local wind. Neither data collection, nor satellite images or model simulations alone were able to explain the observed spatial patterns and transport processes. Therefore, all these methods were combined to explain the dynamical features and to systematise them according to the typical local wind pattern and time series. The aim was to develop an instrument for regional authorities which supports the interpretation of coastal water monitoring data and forms a basis for an improved monitoring strategy. Satellite data of sea surface temperature and ocean colour from the sensors NOAA-AVHRR and SeaWiFS were applied for synoptic investigations in the entire region and Landsat-7-ETM+ for regional studies. Model simulations were performed for the western Baltic using a 3D model MOM-3 and for the Szczecin Lagoon using 2D model FEMFLOW. For the first time, regional particularities in the coastal dynamical features and processes are derived for the main wind directions and for transitions between dominant wind situations west and east as derived from wind statistics. The simulated transport of particles released from different coastal and open sea sources indicate the affected areas during changing forcing conditions. The results support the interpretation of acquired coastal monitoring data as well as the assessment and optimisation of the monitoring programme.  相似文献   

Regional gravity modeling in terms of spherical base functions     

Michael Schmidt  Martin Fengler  Torsten Mayer-Gürr  Annette Eicker  Jürgen Kusche  Laura Sánchez  Shin-Chan Han 《Journal of Geodesy》2007,81(1):17-38

This article provides a survey on modern methods of regional gravity field modeling on the sphere. Starting with the classical theory of spherical harmonics, we outline the transition towards space-localizing methods such as spherical splines and wavelets. Special emphasis is given to the relations among these methods, which all involve radial base functions. Moreover, we provide extensive applications of these methods and numerical results from real space-borne data of recent satellite gravity missions, namely the Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE). We also derive high-resolution gravity field models by effectively combining space-borne and surface measurements using a new weighted level-combination concept. In addition, we outline and apply a strategy for constructing spatio-temporal fields from regional data sets spanning different observation periods.  相似文献   

Indications for pedogenic formation of perylene in a terrestrial soil profile: Depth distribution and first results from stable carbon isotope ratios     

Tilman Gocht  Johannes A.C. Barth  Michaela Epp  Maik Jochmann  Michaela Blessing  Torsten C. Schmidt  Peter Grathwohl 《Applied Geochemistry》2007,22(12):2652

Concentrations and isotope compositions of polycyclic aromatic hydrocarbons (PAHs) were determined in natural soils of Southern Germany. In selected profiles perylene concentrations increased with soil depth when compared to the other PAH compounds present. However, its low solubility made vertical transport by seepage water unlikely. Therefore two mechanisms are discussed that could have caused the unusual distribution of perylene in these soils:

(a) Atmospheric deposition of combustion-derived (i.e. pyrogenic) perylene in the top-soil and

(b) in situ generation in the sub-soil of these specific terrestrial environments. This could have been caused by microbial activities or other catalytic processes yet unknown.

In order to distinguish between pyrogenic and natural generation compound-specific ¹³C/¹²C ratios (δ¹³C) were compared between perylene and other PAHs in samples from the top-soil and sub-soil. Despite successful clean-up of the extracts, low perylene concentrations and peak overlaps with benzo(e)pyrene and benzo(a)pyrene prevented determination of a unique δ¹³C value for perylene in the upper horizon. However, the δ¹³C value of perylene in the sub-soil was 5.7 permille more negative than other equal-mass PAHs (with m/z of 252) in the top-soil, which rather supports in situ generation of perylene in the sub-soil.  相似文献   

Erosion and Flooding—Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island,Yukon Territory,Canada     

Boris Radosavljevic  Hugues Lantuit  Wayne Pollard  Paul Overduin  Nicole Couture  Torsten Sachs  Veit Helm  Michael Fritz 《Estuaries and Coasts》2016,39(4):900-915

Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale. The objectives of this paper are to provide such a tool by assessing potential erosion and flood hazards at Herschel Island, a UNESCO World Heritage candidate site. This study focused on Simpson Point and the adjacent coastal sections because of their archeological, historical, and cultural significance. Shoreline movement was analyzed using the Digital Shoreline Analysis System (DSAS) after digitizing shorelines from 1952, 1970, 2000, and 2011. For purposes of this analysis, the coast was divided in seven coastal reaches (CRs) reflecting different morphologies and/or exposures. Using linear regression rates obtained from these data, projections of shoreline position were made for 20 and 50 years into the future. Flood hazard was assessed using a least cost path analysis based on a high-resolution light detection and ranging (LiDAR) dataset and current Intergovernmental Panel on Climate Change sea level estimates. Widespread erosion characterizes the study area. The rate of shoreline movement in different periods of the study ranges from ?5.5 to 2.7 m·a^?1 (mean ?0.6 m·a^?1). Mean coastal retreat decreased from ?0.6 m·a^?1 to ?0.5 m·a^?1, for 1952–1970 and 1970–2000, respectively, and increased to ?1.3 m·a^?1 in the period 2000–2011. Ice-rich coastal sections most exposed to wave attack exhibited the highest rates of coastal retreat. The geohazard map combines shoreline projections and flood hazard analyses to show that most of the spit area has extreme or very high flood hazard potential, and some buildings are vulnerable to coastal erosion. This study demonstrates that transgressive forcing may provide ample sediment for the expansion of depositional landforms, while growing more susceptible to overwash and flooding.  相似文献   

On the automatic parameter calibration of a hypoplastic soil model     

Machaček  Jan  Staubach  Patrick  Tavera  Carlos Eduardo Grandas  Wichtmann  Torsten  Zachert  Hauke 《Acta Geotechnica》2022,17(11):5253-5273

Acta Geotechnica - This paper presents an approach for the automatic parameter calibration (AC) of a hypoplastic constitutive soil model. The calibration software developed in this work simplifies...  相似文献   

A state-dependent hyperelastic-plastic constitutive model considering shear-induced particle breakage in granular soils     

Irani  Nazanin  Lashkari  Ali  Tafili  Merita  Wichtmann  Torsten 《Acta Geotechnica》2022,17(11):5275-5298

Acta Geotechnica - An elastic–plastic constitutive model considering particle breakage for simulation of crushable granular soils behavior is proposed. In the model, elastic strain rates are...  相似文献   

Decision bias in marine spatial planning of offshore wind farms: Problems of singular versus cumulative assessments of economic impacts on fisheries     

Jörg Berkenhagen  Ralf Döring  Heino O. Fock  Matthias H.F. Kloppmann  Søren A. Pedersen  Torsten Schulze 《Marine Policy》2010

The current approval procedure for wind farm proposals in the German EEZ only considers site specific conflict analysis between the wind farm and fisheries. Due to the relatively small spatial coverage of the sites potential opportunity losses to the fisheries are always considered as low or negligible. Cumulative effects on fisheries that will occur once all proposed wind farms are in place are not yet considered adequately. However, those cumulative effects will be quite substantial because, in particular, opportunities to catch such valuable species as flatfish will be considerably reduced.  相似文献