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排序方式: 共有830条查询结果,搜索用时 15 毫秒
821.
Katrin M. Nissen Uwe Ulbrich Gregor C. Leckebusch Ivan Kuhnel 《Climate Dynamics》2014,43(5-6):1545-1555
The relationship between decadal variations in the North Atlantic meridional overturning circulation (MOC) and North Atlantic/Western European windstorm activity during the extended winter season is studied. According to an ensemble of three 240-year long simulations performed with the ECHAM5-MPIOM model, periods of high decadal windstorm activity frequently occur in the years following a phase of weak MOC (i.e. when the MOC starts to recover). These periods are characterised by a distinctive pattern in the mixed layer ocean heat content (OHC). A positive anomaly is located in the region 45°N?52°N/35°W?16°W (west of France). Negative anomalies are located to the North and South. The signal can be detected both in the heat content of the oceanic mixed layer and in the sea surface temperatures. Its structure is consistent with anomalously enhanced baroclinic instability in the region with the strong negative OHC gradient (30°W?10°W/45°N?60°N), which eventually produces a higher probability of windstorms. 相似文献
822.
Residuals from agricultural pesticides threaten the environment and human health. Climate change alters these externalities because it affects pest pressure and pesticide application rates. This study examines damages from pesticide externalities in US agriculture under different climate projections and the effects of alternative regulations. We find divergent impacts of externality regulation and climate change on agricultural production in the US. A Pigovian tax on pesticide externalities generally increases crop production cost, but farm revenue improves because of increased commodity prices. Climate change generally decreases US farm revenue because production increases and prices fall. Results also show a heterogeneous effect of climate change on pest management intensities across major crops. 相似文献
823.
Optimal mitigation strategies with negative emission technologies and carbon sinks under uncertainty
Sabine Fuss Wolf Heinrich Reuter Jana Szolgayová Michael Obersteiner 《Climatic change》2013,118(1):73-87
In recent years a body of literature has arisen on the topic of how to compose the optimal portfolio of mitigation options. The focus has been mainly on options involving shifts from high- to low- or even negative-carbon technologies. Natural sinks play an important role in any attempt to stabilize atmospheric CO2 and usually enter as a constant term in the overall carbon budget. In this paper, we introduce natural sinks to the carbon management problem and analyze the implications for negative emission technology deployment and the overall mitigation strategy. Amongst other sensitivity analyses, we also investigate the impact of uncertainty in the carbon sink, which we find to raise the importance of negative emissions in the mitigation portfolio significantly lowering the cost of the policy mix. 相似文献
824.
I. N. Ezau T. Wolf E. A. Miller I. A. Repina Yu. I. Troitskaya S. S. Zilitinkevich 《Russian Meteorology and Hydrology》2013,38(10):715-722
Considered is the application of MTP-5 meteorological temperature profiler used for the remote sensing of vertical profiles of the air temperature in the planetary boundary layer and the lower one-kilometer layer of the atmosphere. The measurements were carried out in Bergen (Norway) in 2011–2012. The obtained dataset of temperature profiles has temporal resolution of five minutes and vertical resolution of 50 m. The MTP-5 data are complemented with the measurements of the air temperature and the wind taken at two automatic weather stations and with the measurements of the rain intensity made with the rain radar. Studied is the impact of meteorological conditions and precipitation on the MTP-5 readings. It is revealed that formation of a thin water film (of ice or, to a smaller degree, of sleet) on the surface of the sensor cover of MTP-5 has a significant impact on the data of the temperature monitoring. The removal of intensive precipitation (the precipitation rate is >0.2 mm/hour) improved the reliability and quality of the temperature profile monitoring. In particular, it is demonstrated that significant air pollution and stably stratified atmospheric conditions which lead to low temperatures are reliably monitored with this instrument. 相似文献
825.
Zamponi Joaquin Giannetti Andrea Bovino Stefano Sabatini Giovanni Schleicher Dominik R. G. Krtgen Bastian Reissl Stefan Wolf Sebastian 《Astrophysics and Space Science》2022,367(6):1-9
Astrophysics and Space Science - Dynamical evolution of galaxies is a complex process, especially the centers. Gravitationally coupled gas and stellar discs have been observed to coexist in the... 相似文献
826.
Experimental study of mechanical and hydraulic properties of bedded rock salt from the Jintan location 总被引:1,自引:0,他引:1
Wei Xing Juan Zhao Uwe Düsterloh Dieter Brückner Zhengmeng Hou Lingzhi Xie Jianfeng Liu 《Acta Geotechnica》2014,9(1):145-151
A series of triaxial compression tests, triaxial extension tests, and triaxial compression creep tests were conducted to evaluate the strength, deformability, and permeability of rock salt from the Jintan location. Based on a previous analysis, the measured data can be physically modeled very well as shown by the constitutive model Hou/Lux and indicate that China’s representative bedded rock salt from the Jintan location is characterized by good ductility and deformation properties, similar to the European high-purity rock salt. Based on a comparison of compression as well as extension failure strength determined at rock salt from Jintan location, a similarity of compression and extension failure strength could be demonstrated. Permeation flow seems to be an anisotropic process because the permeability measured at samples prior to failure by compression tests differs to those measured at samples prior to failure by extension tests. The anisotropy of damage and destruction of rock salt has a significant influence on permeability. In case of triaxial compression tests, the measured permeability increases two to six orders of magnitude because of consistent direction of injection and cracks. In case of triaxial extension tests, however, the permeability increases less with a maximum of two orders in magnitude. The test results are significant for understanding the load-bearing behavior of rock salt from Jintan location and investigations with reference to the stability and tightness of underground caverns. 相似文献
827.
Victoria Burke Doreen Richter Ulrike Hass Uwe Duennbier Janek Greskowiak Gudrun Massmann 《Environmental Earth Sciences》2014,71(8):3685-3695
The biodegradation of various wastewater-derived organic trace pollutants occurring in different aquatic compartments of the environment was previously reported to be influenced by the prevailing redox conditions. However, comparative studies on the redox-dependent degradation behavior of organic trace pollutants are scarce. The objective of the study presented herein, was to compile and evaluate data from several comparable previous tank experiments, thus, providing an overview on the redox-dependent removal of a total of 27 wastewater-derived trace compounds, including phenazone type compounds, antimicrobials, ß-blockers, psychoactive drugs and sulfonamides. Removal rate constants were fitted assuming first-order degradation kinetics. Six compounds were identified to be removed solely under oxic, three compounds solely under anoxic conditions. Others persisted under all experimental conditions, while some were removed under both oxic and anoxic conditions. 相似文献
828.
Uwe R. Kackstaetter 《Central European Journal of Geosciences》2014,6(2):170-181
Normative mineralogical calculations from bulk geochemistry of sedimentary rocks are problematic because of variable depositional environments, particle hydraulics and sedimentary source systems. The development of SEDMIN, a Microsoft Excel? spreadsheet solution, is a practical attempt for a computational routine focusing specifically on smectite, chlorite, kaolinite, illite and the ambiguous sericite within various pelitic sedimentary lithologies. While in essence a mathematical approach, the use of statistical evaluation of empirical lithogeochemical data combined with modal analytical procedures yields reasonable geochemical associations, more precise chemical phases and revised procedural allotment paradigms. Thus, an algorithm using TiO2 as a key to the normative calculation of kaolinite is proposed. Incorporating additional parameters, such as LOI (Loss-on-ignition) in conjunction with carbon, sulfur, carbonate and sulfate, provides that clay phases can be more accurately determined than from bulk oxides alone. Even when presented with atypical sample data, the spreadsheet solution is able to accurately predict predominant clay minerals. Besides some drawbacks, the likely benefit from SEDMIN is the incorporation of results in classification norms and diagrams indicative of sedimentary lithologies. The ”SEDMIN Sedimentary Mineral Calculator.xlsx” spreadsheet can be freely downloaded from http://earthscienceeducation.net/SEDMINSedimentaryMineralCalculator.xlsx. 相似文献
829.
C. Wolf 《Astronomische Nachrichten》1992,313(3):133-137
Looking for repetitive signals within a γ burst may provide evidence for a massive KeV pseudo-scalar coupled to electromagnetism. We study the possible signatures that may occur for pseudo-scalar electromagnetic propagation and outline possible probes to the pseudo-scalar mass as well as its coupling to electromagnetism. 相似文献
830.
Three eclipsing binary systems with astrometric orbit have been studied. For a detailed analysis two circular‐orbit binaries (VW Cep and HT Vir) and one binary with an eccentric orbit (ζ Phe) have been chosen. Merging together astrometry and the analysis of the times of minima, one is able to describe the orbit of such a system completely. The O – C diagrams and the astrometric orbits of the third bodies were analysed simultaneously for these three systems by the least‐squares method. The introduced algorithm is useful and powerful, but also time consuming, due to many parameters which one is trying to derive. The new orbits for the third bodies in these systems were found with periods 30, 221, and 261 yr, and eccentricities 0.63, 0.37, and 0.64 for VWCep, ζ Phe, and HT Vir, respectively. Also an independent approach to compute the distances to these systems was used. The use of this algorithm to VW Cep gave the distance d = (27.90 ± 0.29) pc, which is in excellent agreement with the previous Hipparcos result. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献