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181.
Jonas Lundberg 《Solar physics》1994,154(2):215-230
The weakly nonlinear wave propagation of a slow sausage surface wave traveling along a magnetized slab with a thin nonuniform boundary layer is considered. The ideal incompressible MHD equations are used and the nonlinearities are assumed to be due to second harmonic generation. A nonlinear dispersion relation and the related nonlinear Schrödinger equation is derived. The existence of a continuous thin interface leads to sharply peaked field amplitudes due to resonant interaction with local Alfvén waves. It is shown that the nonlinear effects from processes within the thin layer are much more important than those from the main slab. Furthermore, the nonlinear interaction with local Alfvén waves yields a nonlinear damping rate of the wave that is much larger than the linear damping rate when the transition layer is sufficiently thin. 相似文献
182.
Norbert Kasch Marco Naujoks Jonas Kley Thomas Jahr 《International Journal of Earth Sciences》2013,102(5):1257-1270
Geodynamic observatories around the globe continuously monitor signals like gravity, tilt and strain as a function of time. However, global signals are often masked by local effects, caused by the direct surroundings of the station, including the local geological setting. This link is well established for superconducting gravimeters (SG) that observe the gravity field variations at very high resolution. An enhancement of the SG time series by the application of local correction is exemplarily shown here in a very practicable procedure for the Geodynamic Observatory Moxa, Germany. We show how the combination of geological and gravimetrical mapping and modelling around Moxa results in a significant correction of the original gravity data, as can be proven by comparison with the satellite-derived gravity field. Detailed geological mapping of the observatory surroundings, including measurements of fold axes, foliations and joints, was the basis of the present study. The fold structure in the area of interest was interpreted by geometrical 3D modelling. The complete representation of different rock types in space also provides a better understanding of the local hydro-geological situation. Using a combination of the 3D geological model with the high-resolution Bouguer map of the observatory surroundings, we developed a 3D density model. This model enables the correction of small gravity effects caused by mass variations close to the SG, in particular local hydro-geological mass changes. Thus, the procedure presented here, based on a close connection of geology and gravimetry, is a powerful tool for the reduction of local gravity effects on SG recordings. It should be applicable to SG stations worldwide, where similar hydrologically driven mass changes can be assumed. 相似文献
183.
Total uncertainty in greenhouse gas (GHG) emissions changes over time due to “learning” and structural changes in GHG emissions. Understanding the uncertainty in GHG emissions over time is very important to better communicate uncertainty and to improve the setting of emission targets in the future. This is a diagnostic study divided into two parts. The first part analyses the historical change in the total uncertainty of CO2 emissions from stationary sources that the member states estimate annually in their national inventory reports. The second part presents examples of changes in total uncertainty due to structural changes in GHG emissions considering the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) emissions scenarios that are consistent with the EU’s “20-20-20” targets. The estimates of total uncertainty for the year 2020 are made under assumptions that relative uncertainties of GHG emissions by sector do not change in time, and with possible future uncertainty reductions for non-CO2 emissions, which are characterized by high relative uncertainty. This diagnostic exercise shows that a driving factor of change in total uncertainty is increased knowledge of inventory processes in the past and prospective future. However, for individual countries and longer periods, structural changes in emissions could significantly influence the total uncertainty in relative terms. 相似文献
184.
Matthias Jonas Gregg Marland Volker Krey Fabian Wagner Zbigniew Nahorski 《Climatic change》2014,124(3):459-476
Our study focuses on uncertainty in greenhouse gas (GHG) emissions from anthropogenic sources, including land use and land-use change activities. We aim to understand the relevance of diagnostic (retrospective) and prognostic (prospective) uncertainty in an emissions-temperature setting that seeks to constrain global warming and to link uncertainty consistently across temporal scales. We discuss diagnostic and prognostic uncertainty in a systems setting that allows any country to understand its national and near-term mitigation and adaptation efforts in a globally consistent and long-term context. Cumulative emissions are not only constrained and globally binding but exhibit quantitative uncertainty; and whether or not compliance with an agreed temperature target will be achieved is also uncertain. To facilitate discussions, we focus on two countries, the USA and China. While our study addresses whether or not future increase in global temperature can be kept below 2, 3, or 4 °C targets, its primary aim is to use those targets to demonstrate the relevance of both diagnostic and prognostic uncertainty. We show how to combine diagnostic and prognostic uncertainty to take more educated (precautionary) decisions for reducing emissions toward an agreed temperature target; and how to perceive combined diagnostic and prognostic uncertainty-related risk. Diagnostic uncertainty is the uncertainty contained in inventoried emission estimates and relates to the risk that true GHG emissions are greater than inventoried emission estimates reported in a specified year; prognostic uncertainty refers to cumulative emissions between a start year and a future target year, and relates to the risk that an agreed temperature target is exceeded. 相似文献
185.
Jens Wendler Jens Köster Jens Götze Norbert Kasch Norbert Zisser Jonas Kley Dieter Pudlo Georg Nover Reinhard Gaupp 《International Journal of Earth Sciences》2012,101(1):159-176
Fracture-related bleaching of Lower Triassic Buntsandstein red beds of central Germany was related to significant carbonate
diagenesis and feldspar alteration caused by CO2-rich fluids. Using cathodoluminescence microscopy and spectroscopy combined with electron microprobe analysis and stable
carbon isotope study, two major fluid–mineral interactions were detected: (1) zoned, joint-filling calcites and zoned pore-filling
calcite cements, the latter replacing an earlier dolomite, were formed during bleaching. During the calcite formation and
dolomite–calcite transformation, iron was incorporated into the calcite cement crystal cores due to Fe availability from the
coeval bleaching. The dedolomitisation was ultimately associated with a volume increase. The related permeability decrease
implies a certain degree of sealing and increasing retention of CO2, and the volume increase offers a minor CO2 sink. Carbonate-rich sandstone, therefore, can provide advantages for underground CO2 storage especially when situated in the fringes of the reservoir. (2) Alkali-feldspar alteration due to the bleaching fluids
is reflected in cathodoluminescence spectra predominantly by the modulation of a brown luminescence emission peak (~620 nm).
This peak represents a newly discovered effect related to alkali-feldspar alteration not solely associated with bleaching.
Its modulation by the bleaching is interpreted to be due to Na depletion or a lattice defect in the Si–O bonds of the SiO4-tetrahedron. Alteration reflected by this luminescence feature has a destructive effect on the feldspars implying the possibility
of diminished rock integrity due to bleaching and, hence, CO2-rich fluids. Two further CL spectral changes related to bleaching occur, (a) decreased intensity between around 570 nm assigned
to Mn-depletion, and (b) increased amplitude and wavelength shift of the red (~680 nm) band. Converging evidence from carbonate
and feldspar diagenesis, stable carbon isotope data and analysis of fracture directions suggests that CO2 fluids contributed to a significant extent to the bleaching phenomena and alteration in the studied Buntsandstein strata. 相似文献
186.
The mountain belts of the Dzungarian Alatau (SE Kazakhstan) and the Tien Shan are part of the actively deforming India–Asia collision zone but how the strain is partitioned on individual faults remains poorly known. Here we use terrace mapping, topographic profiling, and 10Be exposure dating to constrain the slip rate of the 160-km-long Usek thrust fault, which defines the southern front of the Dzungarian Alatau. In the eastern part of the fault, where the Usek River has formed five terraces (T1–T5), the Usek thrust fault has vertically displaced terrace T4 by 132 ± 10 m. At two sites on T4, exposure dating of boulders, amalgamated quartz pebbles, and sand from a depth profile yielded 10Be ages of 366 ± 60 ka and 360 + 77/− 48 ka (both calculated for an erosion rate of 0.5 mm/ka). Combined with the vertical offset and a 45–70° dip of the Usek fault, these age constraints result in vertical and horizontal slip rates of ~ 0.4 and ~ 0.25 mm/a, respectively. These rates are below the current resolution of GPS measurements and highlight the importance of determining slip rates for individual faults by dating deformed landforms to resolve the pattern of strain distribution across intracontinental mountain belts. 相似文献
187.
During Typhoon Morakot which hit Taiwan from 6 to 9 August, 2009, Kaohsiung City was highly affected by devastating debris-flows and flooding. Recorded casualties were 699 deaths and 1,766 damaged homes, mostly in the mountainous areas of Kaohsiung City. Due to a largely malfunctioning or absent early-warning system, residents in those mountainous villages were required to rely on individual- and/or community-based capacities to evacuate and respond to debris-flow-related disasters. Hence, this study investigates the response behaviour of selected debris-flow-affected communities in Kaohsiung City, based on a preparedness awareness action and affect model. Key results from the survey highlight that only 13.8 % of the households received formal (institutional) early warning, whereas 86.2 % households had to rely on their intrinsic senses and indigenous knowledge to recognise the onset of debris-flows in their villages during Typhoon Morakot. Among those households who did not receive formal early warning, 10 % of the households received previous disaster education, 17 % had previous disaster experience, and 73 % did have neither disaster education nor disaster experience. Furthermore, households with disaster education were among those who were best prepared and knew best how to evacuate and respond to debris-flow-related disasters followed by households with disaster experiences. Finally, findings from the survey and selected key informants’ interviews identified that the response behaviour of communities ought to be enhanced through the following measures: conduction of hydro-meteorological-related disaster education, improved participatory risk communication and enhanced recognition of communities as vital actors during a disaster to provide local knowledge and support to relief operations. 相似文献
188.
Robert Mokrik Vytautas Juodkazis Anicetas Štuopis Jonas Mažeika 《Hydrogeology Journal》2014,22(4):925-941
A steady-state groundwater flow model of three Quaternary intertill aquifers in the eastern part of Lithuania has been compiled. The distinction of separate modelled layers is based on hydraulic and isotope-hydrochemistry data criteria. 3H data were used to estimate the corrected groundwater age and were coupled with a groundwater-flow-dynamics model of the Quaternary aquifer system along a cross-section flow pathway from the Baltic Upland recharge area in eastern Lithuania towards the discharge area in the lowlands near the city of Kaunas in central Lithuania. The bicarbonate content in groundwater (214–462 mg/l) increases downgradient towards the lowland area. The other major constituents and total dissolved solids (TDS) have a trend analogous to the bicarbonate. The 14C activity of dissolved inorganic carbon (DIC) in the groundwater ranges from 41.4 to 85.7 pMC. With aquifer-system depth, active precipitation of aqueous solution takes place by dissolving minerals of calcite and dolomite and leakage of “old” groundwater from lower aquifers; the process is also traced by lower 14C and 3H activities and by more positive δ18O values in lowland areas. 相似文献