Influence of the Indian Ocean Dipole on tree-ring δ18O of monsoonal Southeast Tibet     

Philipp Hochreuther  Jakob Wernicke  Jussi Grießinger  Thomas Mölg  Haifeng Zhu  Lily Wang  Achim Bräuning 《Climatic change》2016,137(1-2):217-230

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Effects of using inclined parametric echosounding on sub-bottom acoustic imaging and advances in buried object detection   总被引：1，自引：0，他引：1  

Jens Schneider von Deimling  Philipp Held  Peter Feldens  Dennis Wilken 《Geo-Marine Letters》2016,36(2):113-119

This study reports an adaptation of a parametric echosounder system using 15 kHz as secondary frequency to investigate the angular response of sub-bottom backscatter strength of layered mud, providing a new method for enhanced acoustic detection of buried targets. Adaptions to achieve both vertical (0°) and non-vertical inclination (1–15°, 30°, 45° and 60°) comprise mechanical tilting of the acoustic transducer and electronic beam steering. Data were acquired at 18 m water depth at a study site characterized by a flat, muddy seafloor where a 0.1 m diameter power cable lies 1–2 m below the seafloor. Surveying the cable with vertical incidence revealed that the buried cable can hardly be discriminated against the backscatter strength of the layered mud. However, the backscatter strength of layered mud decreases strongly at >3±0.5° incidence and the layered mud echo pattern vanishes beyond 5°. As a consequence, the backscatter pattern of the buried cable is very pronounced in acoustic images gathered at 15°, 30°, 45° and 60° incidence. The size of the cable echo pattern increases linearly with incidence. These effects are attributed to reflection loss from layered mud at larger incidence and to the scattering of the 0.1 m diameter buried cable. Data analyses support the visual impression of superior detection of the cable with an up to 2.6-fold increase of the signal-to-noise ratio at 40° incidence compared to the vertical incidence case.  相似文献   

Trading more food: Implications for land use,greenhouse gas emissions,and the food system     

Christoph Schmitz  Anne Biewald  Hermann Lotze-Campen  Alexander Popp  Jan Philipp Dietrich  Benjamin Bodirsky  Michael Krause  Isabelle Weindl 《Global Environmental Change》2012,22(1):189-209

The volume of agricultural trade increased by more than ten times throughout the past six decades and is likely to continue with high rates in the future. Thereby, it largely affects environment and climate. We analyse future trade scenarios covering the period of 2005–2045 by evaluating economic and environmental effects using the global land-use model MAgPIE (“Model of Agricultural Production and its Impact on the Environment”). This is the first trade study using spatially explicit mapping of land use patterns and greenhouse gas emissions. We focus on three scenarios: the reference scenario fixes current trade patterns, the policy scenario follows a historically derived liberalisation pathway, and the liberalisation scenario assumes a path, which ends with full trade liberalisation in 2045.Further trade liberalisation leads to lower global costs of food. Regions with comparative advantages like Latin America for cereals and oil crops and China for livestock products will export more. In contrast, regions like the Middle East, North Africa, and South Asia face the highest increases of imports. Deforestation, mainly in Latin America, leads to significant amounts of additional carbon emissions due to trade liberalisation. Non-CO₂ emissions will mostly shift to China due to comparative advantages in livestock production and rising livestock demand in the region. Overall, further trade liberalisation leads to higher economic benefits at the expense of environment and climate, if no other regulations are put in place.  相似文献   

Fracture flow modelling based on satellite images of the Wajid Sandstone, Saudi Arabia   总被引：1，自引：0，他引：1  

Conny Zeeb  Daniel Göckus  Paul Bons  Hussain Al Ajmi  Randolf Rausch  Philipp Blum 《Hydrogeology Journal》2010,18(7):1699-1712

Large-scale geological features have been identified by satellite imagery and global positioning system data in the Wajid Sandstone in Saudi Arabia. The main objective is to evaluate the importance of fractures for the overall flow behaviour in this fractured rock aquifer and to estimate in-situ hydraulic apertures. Data on fractures and lineaments were available for three outcrops. By applying a “cut-out” routine on the fracture endpoint data of these fracture trace windows, three deterministic discrete fracture networks (DFN), with an area of 100 m?×?100 m, could be generated. These were used to simulate the fracture flow and to determine the hydraulic conductivity tensors. Using additional data on hydraulic pumping tests and matrix conductivities, in-situ hydraulic apertures could be determined. Average in-situ hydraulic apertures range from 1,300 to 1,700 µm. Observations from the field support these results. In addition, a hydraulic conductivity ratio between the matrix and fracture system was used to identify the contribution of the DFN to the overall fluid transport. A ratio of 10.4 was determined, which indicates that the effective flow behaviour in the Wajid Sandstone aquifer is not entirely dominated by the fracture system, though evidently strongly controlled by it.  相似文献   

Earthquakes in Switzerland and surrounding regions during 2009     

Nicholas Deichmann  John Clinton  Stephan Husen  Benjamin Edwards  Florian Haslinger  Donat Fäh  Domenico Giardini  Philipp Kästli  Urs Kradolfer  Iris Marschall  Stefan Wiemer 《Swiss Journal of Geoscience》2010,103(3):535-549

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2009. During this period, 450 earthquakes and 68 quarry blasts were detected and located in the region under consideration. The three strongest events occurred about 15 km NW of Basel in southern Germany (M_L 4.2), near Wildhaus in the Toggenburg (M_L 4.0) and near Bivio in Graubünden (M_L 3.5). Although felt by the population, they were not reported to have caused any damage. With a total of 24 events with M_L ≥ 2.5, the seismic activity in the year 2009 was close to the average over the previous 34 years.  相似文献   

Speleogenesis and deposition of sediments in Cioclovina Uscată Cave,Sureanu Mountains,Romania     

Anamaria Diana Häuselmann  Philipp Häuselmann  Bogdan Petroniu Onac 《Environmental Earth Sciences》2010,61(8):1561-1571

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Evaluation of the representative elementary volume (REV) of a fractured geothermal sandstone reservoir   总被引：3，自引：3，他引：0  

Christian Müller  Siegfried Siegesmund  Philipp Blum 《Environmental Earth Sciences》2010,61(8):1713-1724

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Evaluating spatial scales of climate variability in sub-Saharan Africa     

M. Jury  H. Rautenbach  M. Tadross  A. Philipp 《Theoretical and Applied Climatology》2007,88(3-4):169-177

Summary Spatial scales of variability in seasonal rainfall over Africa are investigated by means of statistical and numerical techniques. In the statistical analysis spatial structure is studied using gridded 0.5° resolution monthly data in the period 1948–1998. The de-seasonalized time series are subjected to successive principal component (PC) analysis, allowing the number of modes to vary from 10 to 24, producing cells of varying dimension. Then the original rainfall data within each cell are cross-correlated (internal), then averaged and compared with the adjacent cells (external) for each PC solution. By considering the ratio of internal to external correlation, the spatial scales of rainfall variability are evaluated and an optimum solution is found whose cell dimensions are approximately 10⁶ km². The aspect of scale is further studied for southern Africa by consideration of numerical model ensemble simulations over the period 1985–1999 forced with observed sea surface temperatures (SSTs). The hindcast products are compared with observed January to March (JFM) rainfall, based on a station-satellite merged analysis of precipitation (CMAP) data at 2.5° resolution. Validations for different sized areas indicate that cumulative standardized errors are greatest at the scale of a single grid cell (10⁴ km²) and decrease 20–30% by averaging over successively larger areas (10⁶ km²).  相似文献   

The earthquake of 250 a.d. in Augusta Raurica, A real event with a 3D site-effect?     

Donat Fäh  Sibylle Steimen  Ivo Oprsal  Johannes Ripperger  Jochen Wössner  Regula Schatzmann  Philipp Kästli  Ina Spottke  Peter Huggenberger 《Journal of Seismology》2006,10(4):459-477

The Roman city Augusta Raurica is located East of Basel, Switzerland. One important topic of the city’s history concerns the hypothesis of an earthquake striking the city in the middle of the third century a.d. This idea had been formulated according to archaeological features and findings, but had not been tested so far. A selection of the archaeological features were reviewed and dated in order to test the hypothesis of a single event. However, archaeological investigations do not draw a conclusive picture; it could not be proven that all features of possible destruction date to the same event. Detailed seismological investigations were performed. These included geological and geotechnical mapping of the unconsolidated sediments. Important parameters such as the thickness and composition of the unconsolidated sediments, the terrain topography and the topography of the bedrock surface were mapped. Ambient vibration H/V measurements provided the fundamental frequency of resonance for the unconsolidated sediments. The velocity of shear waves traveling through sediments is the controlling parameter for amplification of seismic waves. This material property is estimated using the relation between the ellipticity of the fundamental mode Rayleigh wave and the H/V curve. From all information we compiled a three-dimensional model of the surface geology. This model is used to simulate earthquake ground motion and amplification effects in the city, and to map the variability of the amplification. In the part of the city where possible earthquake damage was recognized, amplification occurs in the frequency band of building resonance (2–8 Hz). In the other part of the city amplification occurs much above the building’s resonance. From 1D modelling we estimate a difference in spectral amplification of about a factor of 2.5 to 3 between the two parts of the city. This corresponds approximately to a difference in macroseismic intensity of one unit. 3D modelling showed a large variability of ground motion within very close distance in the part of the city where possible earthquake damage was recognized. The maximum amplification reaches values up to a factor of nine, which is due to 3D effects and the choice of using vertically incident waves. Finally, all paleoseismological findings in the area of Basel were reviewed in order to find indications of a large event in the time-period of interest. Paleoseismological findings provide no hints to a large earthquake in the third century. If we assume that an earthquake caused at least part of the identified damage in Augusta Raurica, we have to assign to this event a magnitude Mw of about 6.0 or even lower, that is much smaller than the value of 6.9 that is actually in the Swiss earthquake catalogue. The earthquake source of this event must then be very close to the site of Augusta Raurica and a strong site-effect occurred in one part of the city.  相似文献   

Heat flow and quantity of methane deduced from a gas hydrate field in the vicinity of the Dnieper Canyon,northwestern Black Sea   总被引：1，自引：1，他引：1  

Thomas?LüdmannEmail author  How?Kin?Wong  Philipp?Konerding  Matthias?Zillmer  J?rg?Petersen  Ernst?Flüh 《Geo-Marine Letters》2004,24(3):182-193

Seismic reflection data document for the first time the existence of a BSR in a limited area west of the Dnieper Canyon in the northwestern Black Sea. Seismic wide-angle data suggest that gas hydrates occupy in average 15±2% of the pore space in a zone of 100 m in thickness. A conservative quantification of the amount of methane associated with this gas hydrate occurrence is about 12±3×10¹¹ m³ (0.6±0.2 Gt of methane carbon). Conductive heat flow deduced from the BSR depth is in the range of 21±6 to 55±15 mW m^–2.  相似文献