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61.
62.
《The Journal of geography》2012,111(3):108-119
AbstractThis article introduces the geographic information systems (GIS) in-service teacher training, focusing on the intersection of technological, pedagogical, and content knowledge (TPACK) for successful implementation of GIS in the classroom. Eleven social studies teachers in Georgia learned GIS technologies, inquiry-based learning, and social studies so that they could create technology-enhanced and inquiry-based lessons using GIS technologies. This article reports participating teachers’ opinions and attitudes of the TPACK-based GIS training. It also reports useful pedagogical methods of introducing GIS technologies to students and additional support for teachers to help them use GIS in their classrooms more often. 相似文献
63.
Consistency of observed winter precipitation trends in northern Europe with regional climate change projections 总被引:1,自引:0,他引:1
Often it is claimed that the recent changes in northern European climate are at least partly anthropogenic even though a human
influence has not yet been successfully detected. Hence we investigate whether the recent changes are consistent with regional
climate change projections. Therefore, trends in winter (DJF) mean precipitation in northern Europe are compared to human
induced changes as predicted by a set of four regional climate model simulations. The patterns of recent trends and predicted
changes match reasonably well as indicated by pattern correlation and the similarity is very likely not random. However, the
model projections generally underestimate the recent change in winter precipitation. That is, the signal-to-noise ratio of
the anthropogenic precipitation change is either rather low or the presently used simulations are significantly flawed in
their ability to project changes into the future. European trends contain large signals related to the North Atlantic Oscillation
(NAO), of which a major unknown part may be unrelated to the anthropogenic signal. Therefore, we also examine the consistency
of recent and projected changes after subtracting the NAO signal in both the observations and in the projections. It turns
out that even after the removal of the NAO signal, the pattern of trends in the observations is similar to those projected
by the models. At the same time, the magnitude of the trends is considerably reduced and closer to the magnitude of the change
in the projections. 相似文献
64.
A good evaluation of the Quaternary uplift of the Rhenish shield is a key element for the understanding of the Cenozoic geodynamics of the western European platform in front of the alpine arc. Previous maps of the massif uplift relied on fluvial incision data since the time of the rivers' Younger Main Terrace to infer a maximum post-0.73 Ma uplift of ~ 290 m in the SE Eifel. Here, we propose a new interpretation of the incision data of the intra-massif streams, where anomalies in the terrace profiles would result from knickpoint retreat in the tributaries of the main rivers rather than from tectonic deformation. We also use additional geomorphological data referring to (1) deformed Tertiary planation surfaces, (2) the history of stream piracy that severely affected the Meuse basin in the last 1 Ma, and (3) incision data outside the Rhenish shield. A new map of the post-0.73 Ma uplift of the Rhenish shield is drawn on the basis of this enlarged dataset. It reduces the maximum amount of tectonic uplift in the SE Eifel to ~ 140 m and modifies the general shape of the uplift, namely straightening its E–W profile. It is also suggested that an uplift wave migrated across the massif, starting from its southern margin in the early Pleistocene and currently showing the highest intensity of uplift in the northern Ardennes and Eifel. These features seem to favour an uplift mechanism chiefly related to lithospheric folding and minimize the impact on the topography of a more local Eifel plume. 相似文献
65.
The interaction between the land surface and the atmosphere is a crucial driver of atmospheric processes. Soil moisture and precipitation are key components in this feedback. Both variables are intertwined in a cycle, that is, the soil moisture – precipitation feedback for which involved processes and interactions are still discussed. In this study the soil moisture – precipitation feedback is compared for the sempiternal humid Ammer catchment in Southern Germany and for the semiarid to subhumid Sissili catchment in West Africa during the warm season, using precipitation datasets from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), from the German Weather Service (REGNIE) and simulation datasets from the Weather Research and Forecasting (WRF) model and the hydrologically enhanced WRF-Hydro model. WRF and WRF-Hydro differ by their representation of terrestrial water flow. With this setup we want to investigate the strength, sign and variables involved in the soil moisture – precipitation feedback for these two regions. The normalized model spread between the two simulation results shows linkages between precipitation variability and diagnostic variables surface fluxes, moisture flux convergence above the surface and convective available potential energy in both study regions. The soil moisture – precipitation feedback is evaluated with a classification of soil moisture spatial heterogeneity based on the strength of the soil moisture gradients. This allows us to assess the impact of soil moisture anomalies on surface fluxes, moisture flux convergence, convective available potential energy and precipitation. In both regions the amount of precipitation generally increases with soil moisture spatial heterogeneity. For the Ammer region the soil moisture – precipitation feedback has a weak negative sign with more rain near drier patches while it has a positive signal for the Sissili region with more rain over wetter patches. At least for the observed moderate soil moisture values and the spatial scale of the Ammer region, the spatial variability of soil moisture is more important for surface-atmosphere interactions than the actual soil moisture content. Overall, we found that soil moisture heterogeneity can greatly affect the soil moisture – precipitation feedback. 相似文献
66.
The study of aerosols and rainwater presented here demonstrates that episodic atmospheric deposition events associated with southeasterly flow are quantitatively significant for large areas of the North Atlantic Ocean. This paper considers aluminium and manganese, with predominantly crustal sources, and lead and zinc, which are mobilised into the atmosphere primarily through anthropogenic activity. High levels of all trace metals are associated with southeasterly flow from Europe as the air passes over heavily populated and industrialised regions before reaching the northeast Atlantic Ocean. Fluxes calculated using the 1% HNO3 acid soluble metal concentration show that, although the climatological norm for this area is westerly flow, short-lived southeasterly transport events dominate the input of trace metals to this ocean region. This material may be toxic to phytoplankton or may be represent a new source of nutrients to the biological community. A significant decrease in atmospheric lead levels in polluted air is seen between June 1996 and May 1997, reflecting the decrease in use of leaded fuels in Europe. Comparing atmospheric flux values to sediment trap metal fluxes shows that the atmosphere represents the dominant source of zinc to the deep ocean, whereas an additional, non-atmospheric, manganese source this required, perhaps from mobilisation of sedimentary material from the continental shelf or long range advection of manganese rich Saharan material. 相似文献
67.
68.
O. Bourgeois M. Ford M. Diraison C. Le Carlier de Veslud M. Gerbault R. Pik N. Ruby S. Bonnet 《International Journal of Earth Sciences》2007,96(6):1003-1031
The development of the Alpine mountain belt has been governed by the convergence of the African and European plates since
the Late Cretaceous. During the Cenozoic, this orogeny was accompanied with two major kinds of intraplate deformation in the
NW-European foreland: (1) the European Cenozoic Rift System (ECRIS), a left-lateral transtensional wrench zone striking NNE-SSW
between the western Mediterranean Sea and the Bohemian Massif; (2) long-wavelength lithospheric folds striking NE and located
between the Alpine front and the North Sea. The present-day geometry of the European crust comprises the signatures of these
two events superimposed on all preceding ones. In order to better define the processes and causes of each event, we identify
and separate their respective geometrical signatures on depth maps of the pre-Mesozoic basement and of the Moho. We derive
the respective timing of rifting and folding from sedimentary accumulation curves computed for selected locations of the Upper
Rhine Graben. From this geometrical and chronological separation, we infer that the ECRIS developed mostly from 37 to 17 Ma,
in response to north-directed impingement of Adria into the European plate. Lithospheric folds developed between 17 and 0 Ma,
after the azimuth of relative displacement between Adria and Europe turned counter-clockwise to NW–SE. The geometry of these
folds (wavelength = 270 km; amplitude = 1,500 m) is consistent with the geometry, as predicted by analogue and numerical models,
of buckle folds produced by horizontal shortening of the whole lithosphere. The development of the folds resulted in ca. 1,000 m of rock uplift along the hinge lines of the anticlines (Burgundy–Swabian Jura and Normandy–Vogelsberg) and ca. 500 m of rock subsidence along the hinge line of the intervening syncline (Sologne–Franconian Basin). The grabens of the
ECRIS were tilted by the development of the folds, and their rift-related sedimentary infill was reduced on anticlines, while
sedimentary accumulation was enhanced in synclines. We interpret the occurrence of Miocene volcanic activity and of topographic
highs, and the basement and Moho configurations in the Vosges–Black Forest area and in the Rhenish Massif as interference
patterns between linear lithospheric anticlines and linear grabens, rather than as signatures of asthenospheric plumes.
相似文献
O. BourgeoisEmail: |
69.
Labour shortage was an integral feature of the communist system of economic management and one that seemed most unlikely to
persist in the face of systemic transformation. A casual examination of the unemployment rates that have emerged throughout
most of Central and Eastern Europe (CEE) during the course of the past decade might suggest that this early assumption was
correct. However, within the region the aggregate rate of joblessness, as well as the behaviour of national output, mask the
fact that certain, major urban centres appear to have weathered well the storms caused by exposure to western markets and
stringent fiscal and monetary policies. In these centres transformation has meant, to a greater or lesser degree, industrial
modernisation and this begs the question of whether the human capital portfolios of the inherited labour force match up to
the requirements of the new environment. This paper examines the meaning of the concept of labour shortage and presents the
findings from a survey of employers in four leading cities of three major CEE economies designed to elicit if, and how, manpower
requirements are being met in the present climate. The results indicate that, somewhat paradoxically, labour shortage persists
in the more flexible markets of the post-communist era and that firms do not expect the situation to change radically in the
near future.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
70.
We report the timing of glaciations during the Late Quaternary in the central Taurus Mountains of Turkey in the Eastern Mediterranean. Forty moraine samples from three glacial valleys on Mount Geyikdağ (36.53°N, 32.10°E, 2877 m), near the Eastern Mediterranean coast of Turkey, were dated with in-situ cosmogenic 36Cl. These glacial valleys are located on the southern flank of the mountain and were filled with few km long glaciers that terminated at elevations of about 1750 m above sea level. Three glacial retreats/advances were determined in this study. During the Last Glacial Maximum (LGM), glaciers reached their maximum positions at 20.6 ± 0.6 ka ago (±1σ). This date is in accordance with the timing of local maximum ice extent, represented by piedmont glaciers in the northern side of the mountain. Glaciers started to retreat after the LGM and shortly stabilized or re-advanced two times before they completely vanished out. The first stage ended before 13.7 ± 0.8 ka ago during the Late-glacial. The last glaciation occurred during the Holocene and ended between 9.6 ± 1.4 ka and 5.9 ± 0.5 ka ago. Later, glaciers mostly vanished from the study area, but a few rock glaciers developed during the Late Holocene. Glacial chronologies of Mount Geyikdağ are mostly comparable with the globally observed advances elsewhere. 相似文献