GIS Teacher Training: Empirically-Based Indicators of Effectiveness     

Steffen Höhnle  Janis Fögele  Rainer Mehren  Jan Christoph Schubert 《The Journal of geography》2016,115(1):12-23

In spite of various actions, the implementation of GIS (geographic information systems) in German schools is still very low. In the presented research, teaching experts as well as teaching novices were presented with empirically based constraints for implementation stemming from an earlier survey. In the process of various group discussions, the participants developed ideas for overcoming the constraints in the field of continuing teacher education among others. These ideas were used to create empirically based strategies for the future design of training activities in continuing education of teachers while taking these constraints into account. These strategies were later validated externally by comparing them to empirical findings on effects of training activities in continuing teacher education in general and empirical findings on GIS implementation from other studies.  相似文献   

Recent innovations in hazard and risk analysis     

Iovine  Giulio  Aubrecht  Christoph  Cohen  Denis  Pastor  Manuel 《Natural Hazards》2018,91(1):1-17

Air pollution has been a major transboundary problem and a matter of global concern for decades. Climate change and air pollution are closely coupled. Just as air pollution can have adverse effects on human health and ecosystems, it can also impact the earth’s climate. As we enter an era of rapid climate change, the implications for air quality need to be better understood, both for the purpose of air quality management and as one of the societal consequences of climate change. In this study, an attempt has been made to estimate the current air quality to forecast the air quality index of an urban station Kolkata (22.65°N, 88.45°E), India for the next 5 years with neural network models. The annual and seasonal variability in the air quality indicates that the winter season is mostly affected by the pollutants. Air quality index (AQI) is estimated as a geometric mean of the pollutants considered. Different neural network models are attempted to select the best model to forecast the AQI of Kolkata. The meteorological parameters and AQI of the previous day are utilized to train the models to forecast the AQI of the next day during the period from 2003 to 2012. The selection of the best model is made after validation with observation from 2013 to 2015. The radial basis functional (RBF) model is found to be the best network model for the purpose. The RBF model with various architectures is tried to obtain precise forecast with minimum error. RBF of 5:5-91-1:1 structure is found to be the best fit for forecasting the AQI of Kolkata.  相似文献   

Can vein-filling speleothems constrain the timing of deep-seated gravitational slope deformation? A case study from the Vinschgau (Italian Alps)     

Gabriella Koltai  Marc Ostermann  Hai Cheng  Christoph Spötl 《Landslides》2018,15(11):2243-2254

The steep, south facing slopes of the central Vinschgau (Val Venosta, South Tyrol, northern Italy) are characterized by deep-seated compound rockslides affecting 51 km² and reaching beneath the Quaternary valley fill. Morphological features include double ridges, trenches, scarps, and counterscarps, whereby the extent of displacement rises from W to E. Near the toe of these slopes, abundant fractures are present whose orientation and spatial strongly suggest that they are related to the gravitational slope deformations. These fractures host carbonate speleothems which are associated with local tufa occurrences at the surface. Given that the metamorphic host rock is essentially carbonate-free, these carbonate deposits require extensive water-rock interactions to form. Modern springs along the toe of the slope are also mostly supersaturated with respect to calcite and locally also aragonite. The invariant chemical composition, very low tritium levels, and in particular the low oxygen isotope values indicate that this groundwater infiltrates at high elevation and is characterized by a long residence time. On the other hand, local infiltration in the lower reaches of the slope is very limited due to the semiarid climate and is incompatible with the measured groundwater stable isotope composition and the high degree of mineralization. We therefore propose a conceptual model which reconciles the deep-seated gravitational slope deformation with the occurrence of mineralized groundwater and associated carbonate precipitates in fractures near the toe of the slope. These deposits provide a means to place constraints on the timing of rock fracturing and hence the slope movements. U/Th dating of 34 samples from eight sites shows that speleothem deposition started 14.2 ka BP and occurred semi-continuously throughout the Holocene. Thus, gravitational displacements likely commenced with a lag of ~3–4 ka after the deglaciation of the valley, which is also consistent with the few available dates on the onset of other deep-seated slope deformations in the Alps.  相似文献   

A tectono-stratigraphic record of an extensional basin: the Lower Jurassic Ab-Haji Formation of east-central Iran     

Mohammad Ali Salehi  Reza Moussavi-Harami  Asadollah Mahboubi  Franz Theodor Fürsich  Markus Wilmsen  Christoph Heubeck 《Swiss Journal of Geoscience》2018,111(1-2):51-78

The Lower Jurassic Ab-Haji Formation consists of siliciclastic strata which are widespread and superbly exposed across the Tabas and Lut blocks of east-central Iran. The formation records the geodynamic history of central Iran during the Early Jurassic in the aftermath of the main Cimmerian event (near the Triassic–Jurassic boundary) through its sedimentary facies and stratigraphic architecture and allows palaeogeographic and palaeoenvironmental reconstructions. We measured and studied three well-exposed outcrop sections and identified lithofacies and facies associations (fluvial plain, delta plain, delta front, prodelta, and shallow-marine siliciclastic shelf). The integration of all geological, stratigraphic, and sedimentological data shows a west-to-east continental-to-marine gradient within the Ab-Haji Formation. Based on thickness variations, lateral facies changes, palaeocurrent patterns, and changes in the nature of the basal contact of the Ab-Haji Formation on the Tabas and Lut blocks, we locate the fault-bounded Yazd Block in the west and the Shotori Swell at the eastern edge of the Tabas Block as provenance regions. The pattern of thickness variations, rapid east–west facies changes, and provenance is best explained by a tectonic model invoking large tilted fault blocks in an extensional basin. The basal unit shows distinct increase in grain size at the base of the Ab-Haji Formation, similar to the Shemshak Group of the Alborz Mountains (the base of the Alasht Formation) and the non-marine time-equivalent succession of the Binalud Mountains of northeastern Iran. This grain size pattern may have been caused by rapid source area uplift due to slab break-off of the subducted Iran plate in the course of the Cimmerian collision in east-central Iran.  相似文献   

Reconstruction of Middle to Late Quaternary sea level using submerged speleothems from the northeastern Yucatán Peninsula     

Simon D. Steidle  Sophie F. Warken  Nils Schorndorf  Julius Förstel  Andrea Schröder-Ritzrau  Gina E. Moseley  Christoph Spötl  Jeronimo Aviles  Wolfgang Stinnesbeck  Norbert Frank 《第四纪科学杂志》2021,36(7):1190-1200

We examined 14 subaerially deposited speleothems retrieved from submerged caves in the northeastern Yucatán Peninsula (Mexico). These speleothems grew during the Middle to Late Quaternary and were dated by ²³⁰Th-U techniques to provide upper depth limits for past sea levels. We report the first relative sea-level limits for Marine Isotope Stages (MIS) 11 and 6, and present new evidence for sea-level oscillations during MIS 5 and early MIS 1. For the latter periods, the origin of growth interruptions is evaluated by combining petrographic methods with trace element analyses. The MIS 5c sea-level highstand probably occurred between 103.94 ± 0.58 ka and 96.82 ± 0.42 ka and must have exceeded -10.8 m (relative to present-day local sea level). The minimum average rate of sea-level fall over a 9.4 ka-long period during the MIS 5e/5d transition is calculated from stalagmite and published coral data at 1.74 ± 0.37 m/ka. For the early Holocene, previous discrepancies with respect to a potential multimetre oscillation of local sea level were found to be challenging to reconcile with the existing speleothem data from the area.  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   

High-resolution isotope records of early Holocene rapid climate change from two coeval stalagmites of Katerloch Cave,Austria     

Ronny Boch  Christoph Spötl  Jan Kramers 《Quaternary Science Reviews》2009,28(23-24):2527-2538

Two coeval stalagmites from Katerloch Cave show pronounced intervals of low δ¹⁸O values around 8.2, 9.1, and 10.0 kyr (all ages are reported before the year 2000 AD) and represent an inorganic U–Th dated climate archive from the southeast of the European Alps, a region where only very few well-dated climate records exist. The O isotope curves, providing near-annual resolution, allow a direct comparison to the Greenland ice core records, as temperature was the primary factor controlling the O isotopic composition of Katerloch speleothems.The 8.2 kyr climate anomaly lasted about one century, from 8196 to 8100 yr, with a maximum amplitude of 1.1‰ at 8175 yr. The event is characterized by a rapid onset and a more gradual demise and U–Th data as well as annual lamina counting support a rapid climate change towards cooler conditions within 10–20 yr. There is no strong evidence that the 8.2 kyr anomaly was superimposed on a pronounced longer-term cooling episode, nor do the new data support two separate cooling events within the 8.2 kyr event as reported by other studies. Our record also shows a distinct climate anomaly around 9.1 kyr, which lasted 70–110 yr and showed a maximum amplitude of 1.0‰, i.e. it had a similar duration and amplitude as the (central) 8.2 kyr event. Compared to the 8.2 kyr event, the 9.1 kyr anomaly shows a more symmetrical structure, but onset and demise still occurred within a few decades only. The different progression of the 8.2 (asymmetrical) and 9.1 kyr anomaly (symmetrical) suggests a fundamental difference in the trigger and/or the response of the climate system. Moreover, both stalagmites show evidence of a climate anomaly around 10.0 kyr, which was of comparable magnitude to the two subsequent events.Using a well constrained modern calibration between air temperature and δ¹⁸O of precipitation for the study area and cave monitoring data (confirming speleothem deposition in Katerloch reflecting cave air temperature), a maximum cooling by ca 3 °C can be inferred at 8.2 and 9.1 kyr, which is similar to other estimates, e.g., from Lake Ammersee north of the Alps. The O isotopic composition of meteoric precipitation, however, is a complex tracer of the hydrological cycle and these temperature estimates do not take into account additional effects such as changes in the source area or synoptic shifts. Apart from that, the relative thickness of the seasonally controlled lamina types in the Katerloch stalagmites remains rather constant across the intervals comprising the isotopic anomalies, i.e. the stalagmite petrography argues against major shifts in seasonality during the early Holocene climate excursions.  相似文献   

Detecting thermal anomalies within the Molasse Basin, southern Germany     

Wolfram Rühaak  Volker Rath  Christoph Clauser 《Hydrogeology Journal》2010,18(8):1897-1915

The groundwater flow regime at great depth within the Molasse Basin (SW Germany) was studied. Data relevant for a flow model at 600–1,600 m depth are sparse in the western part of the basin. However, temperature measurements are available covering much of the area at a wide range of depths. Therefore, a thermal 3D steady-state model was set up with the aim of comparing modeled with observed subsurface temperatures. Stratigraphic information from many boreholes was also available, but only a few values of rock thermal conductivity and heat-production rate could be obtained. Some strong thermal residual anomalies were identified with respect to the purely conductive model, especially along fault zones, and within stratigraphic layers with high hydraulic conductivity. These anomalies can be explained by various advective heat-transport mechanisms, yet most explanations can be eliminated. The most plausible constellation explaining the major positive thermal anomalies of 10 Kelvin and more is a fault zone of E–W strike, intersected by an aquifer with flow parallel to the fault zone. This concept was investigated by using a simplified type model. In spite of some shortcomings, the method presented here can be used to identify temperature anomalies, and to identify possible explanations.  相似文献   

Age constraints on faulting and fault reactivation: a multi-chronological approach   总被引：2，自引：0，他引：2  

Wolfgang Siebel  Horst P. Hann  Martin Danišík  Cosmas K. Shang  Christoph Berthold  Johann Rohrmüller  Klaus Wemmer  Noreen J. Evans 《International Journal of Earth Sciences》2010,99(6):1187-1197

Movement within the Earth’s upper crust is commonly accommodated by faults or shear zones, ranging in scale from micro-displacements to regional tectonic lineaments. Since faults are active on different time scales and can be repeatedly reactivated, their displacement chronology is difficult to reconstruct. This study represents a multi-geochronological approach to unravel the evolution of an intracontinental fault zone locality along the Danube Fault, central Europe. At the investigated fault locality, ancient motion has produced a cataclastic deformation zone in which the cataclastic material was subjected to hydrothermal alteration and K-feldspar was almost completely replaced by illite and other phyllosilicates. Five different geochronological techniques (zircon Pb-evaporation, K–Ar and Rb–Sr illite, apatite fission track and fluorite (U-Th)/He) have been applied to explore the temporal fault activity. The upper time limit for initiation of faulting is constrained by the crystallization age of the primary rock type (known as “Kristallgranit”) at 325 ± 7 Ma, whereas the K–Ar and Rb–Sr ages of two illite fractions <2 μm (266–255 Ma) are interpreted to date fluid infiltration events during the final stage of the cataclastic deformation period. During this time, the “Kristallgranit” was already at or near the Earth’s surface as indicated by the sedimentary record and thermal modelling results of apatite fission track data. (U–Th)/He thermochronology of two single fluorite grains from a fluorite–quartz vein within the fault zone yield Cretaceous ages that clearly postdate their Late-Variscan mineralization age. We propose that later reactivation of the fault caused loss of helium in the fluorites. This assertion is supported by geological evidence, i.e. offsets of Jurassic and Cretaceous sediments along the fault and apatite fission track thermal modelling results are consistent with the prevalence of elevated temperatures (50–80°C) in the fault zone during the Cretaceous.  相似文献   

The biogeochemistry of sorbed methane in marine sediments     

Tobias F. Ertefai  Verena B. Heuer  Christoph Vogt  Jeffrey Seewald 《Geochimica et cosmochimica acta》2010,74(21):6033-6048

Sorption of volatile hydrocarbon gases (VHCs) to marine sediments is a recognized phenomenon that has been investigated in the context of petroleum exploration. However, little is known about the biogeochemistry of sorbed methane and higher VHCs in environments that are not influenced by thermogenic processes. This study evaluated two different extraction protocols for sorbed VHCs, used high pressure equipment to investigate the sorption of methane to pure clay mineral phases, and conducted a geochemical and mineralogical survey of sediment samples from different oceanographic settings and geochemical regimes that are not significantly influenced by thermogenic gas. Extraction of sediments under alkaline conditions yielded higher concentrations of sorbed methane than the established protocol for acidic extraction. Application of alkaline extraction in the environmental survey revealed the presence of substantial amounts of sorbed methane in 374 out of 411 samples (91%). Particularly high amounts, up to 2.1 mmol kg⁻¹ dry sediment, were recovered from methanogenic sediments. Carbon isotopic compositions of sorbed methane suggested substantial contributions from biogenic sources, both in sulfate-depleted and sulfate-reducing sediments. Carbon isotopic relationships between sorbed and dissolved methane indicate a coupling of the two pools. While our sorption experiments and extraction conditions point to an important role for clay minerals as sorbents, mineralogical analyses of marine sediments suggest that variations in mineral composition are not controlling variations in quantities of sorbed methane. We conclude that the distribution of sorbed methane in sediments is strongly influenced by in situ production.  相似文献