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741.
Abstract The Kyoto Protocol has an ambitious reporting and review system to assess Parties' compliance with their emission commitments. It is based on a ‘bottom-up’ approach; that is, each Party is required to submit detailed inventories of emissions and removals. This requires considerable resources and may still not detect all important cases of non-compliance. We consider the case for introducing ‘top-down’ methods; that is, independent inverse modelling methods that calculate probable emissions using measured concentrations of gases in the atmosphere and meteorological models. We argue that the top-down methods are at present too inaccurate, too cumbersome, and politically too problematic to serve as independent alternatives to the reported emission inventories for assessing compliance, although they could be useful in monitoring the global success of the protocol. We conclude that these top-down approaches may supplement the traditional emission inventories, in particular those dealing with fluorinated gases, thereby providing input for improving the emission inventory methods. 相似文献
742.
743.
The landscapes of the world are constantly changing under the influence of human activities leading to the growth of artificial surfaces. The covering of soil by artificial surfaces is referred to as soil sealing. Aerial and satellite images or data derived from them (for instance CORINE land cover — CLC data used here) provide important information that makes it possible to assess the occurrence, area and rate of soil sealing. As the term sealed soil cannot be wholly identified with the content of the appropriate CLC classes, the term land cover flow urbanization (LCFU) will be used here. The essence of this study is the demonstration and documentation of the trends of the LCFU in Europe for the periods 1990–2000 and 2000–2006 on a single map. This may contribute to a better spatial awareness of the ongoing transformation of landscape under the effects of human activities in an pan-European context. Changes in the LCFU can be seen on a map, compiled from 3 × 3 km squares at an all-European scale, using colours and their hues, to fulfil the role both of identification and classification. The colour method employed makes it possible to perceive three groups of LCFU changes on two time horizons, that is, whether the rate of LCFU in 2000–2006 increased or remained the same (hues of red); or dropped compared to the 1990–2000 period (hues of light to dark blue). The third group represents the LCFU with rates higher or lower than the average (countries with changes recorded in only one time horizon are presented in dark and light magenta colours). 相似文献
744.
A 300-kyr record of aridity and wind strength in southwestern Africa: inferences from grain-size distributions of sediments on Walvis Ridge, SE Atlantic 总被引:13,自引:0,他引:13
Jan-Berend W. Stuut Maarten A. Prins Ralph R. Schneider Gert Jan Weltje J. H. Fred Jansen George Postma 《Marine Geology》2002,180(1-4):221-233
The terrigenous fraction of sediments recovered from Walvis Ridge, SE Atlantic Ocean, reveals a history of southwestern African climate of the last 300 kyr. End-member modelling of a data set of grain-size distributions (n=428) results in three end members. The two coarsest end members are interpreted as eolian dust, the third end member as hemipelagic mud. The ratio of the two eolian end members reflects the eolian grain size and is attributed to the intensity of the SE trade winds. Trade winds were intensified during glacials compared to interglacials. Changes in the ratio of the two eolian end members over the hemipelagic one are interpreted as variations in southwestern African aridity. Late Quaternary southwestern African climate was relatively arid during the interglacial stages and relatively humid during the glacial stages, owing to meridional shifts in the atmospheric circulation system. During glacials the polar front shifted equatorward, resulting in a northward displacement of the zone of westerlies, causing increased rainfall in southwestern Africa. The equatorward shift of the polar front is coupled with an increase of the meridional pressure gradient, leading to enhanced atmospheric circulation and increased trade-wind intensity. 相似文献
745.
Addi BISCHOFF Miha JERSEK Thomas GRAU Breda MIRTIC Ulrich OTT Jan KUČERA Marian HORSTMANN Matthias LAUBENSTEIN Siegfried HERRMANN Zdeněk ŘANDA Marc WEBER Gerd HEUSSER 《Meteoritics & planetary science》2011,46(6):793-804
Abstract– On April 9, 2009, at 3:00 CEST, a very bright fireball appeared over Carinthia and the Karavanke Mountains. The meteoroid entered the atmosphere at a very steep angle and disintegrated into a large number of objects. Two main objects were seen as separate fireballs up to an altitude of approximately 5 km, and witnesses reported loud explosions. Three stones were found with a total weight of approximately 3.611 kg. The measured activity of short‐lived cosmogenic radionuclides clearly indicates that two specimens result from a very recent meteorite fall. All cosmogenic radionuclide concentrations suggest a rather small preatmospheric radius of <20 cm; a nominal cosmic‐ray exposure age based on 21Ne is approximately 4 Ma, but the noble gas and radionuclide results in combination indicate a complex irradiation. Jesenice is a highly recrystallized rock with only a few relic chondrules visible in hand specimen and thin section. The texture, the large grain size of plagioclase, and the homogeneous compositions of olivines and pyroxenes clearly indicate that Jesenice is a L6 chondrite. The bulk composition of Jesenice is very close to the published average element concentration for L ordinary chondrites. The chondrite is weakly shocked (S3) as indicated by the undulatory extinction in olivine and plagioclase and the presence of planar fractures in olivine. Being weakly shocked and with gas retention ages of >1.7 Ga (4He) and approximately 4.3 Ga (40Ar), Jesenice seems not to have been strongly affected by the catastrophic disruption of the L‐chondrite parent body approximately 500 Ma ago. 相似文献
746.
Our study has three objectives. We want to investigate (1) whether choropleth maps linked with parallel coordinates help people understand the locations of vulnerable places and the factors making these places vulnerable, (2) whether sparklines that imitate the polylines from a parallel coordinate plot support the understanding of the information provided in that plot, and (3) whether a multiple-view geovisualization approach might be intuitive and useful also for nonexperts. Although we base our work on the functionalities available in the tool called ‘ViewExposed,’ we intend to outline more general conclusions on whether multiple linked views facilitate the understanding of multivariate spatial characteristics. An empirical study with 53 individuals was conducted to obtain insights on these objectives. Our task-based assessment considered the ways in which participants understood the dynamic linking capabilities. Some of the key findings are as follows: (1) even nonexpert users are able to use parallel coordinates linked with choropleth maps; however, only those with extensive inference-making abilities will do so efficiently; (2) parallel coordinates sparklines work as an independent component facilitating the understanding of multivariate data; and (3) the intuitive nature of a multiple-view geovisualization tool is not enough to encourage people to use it. 相似文献
747.
Current state of knowledge regarding the world’s wetlands and their future under global climate change: a synthesis 总被引:1,自引:0,他引:1
Wolfgang J. Junk Shuqing An C. M. Finlayson Brij Gopal Jan Květ Stephen A. Mitchell William J. Mitsch Richard D. Robarts 《Aquatic Sciences - Research Across Boundaries》2013,75(1):151-167
Wetlands cover at least 6 % of the Earth’s surface. They play a key role in hydrological and biogeochemical cycles, harbour a large part of the world’s biodiversity, and provide multiple services to humankind. However, pressure in the form of land reclamation, intense resource exploitation, changes in hydrology, and pollution threaten wetlands on all continents. Depending on the region, 30–90 % of the world’s wetlands have already been destroyed or strongly modified in many countries with no sign of abatement. Climate change scenarios predict additional stresses on wetlands, mainly because of changes in hydrology, temperature increases, and a rise in sea level. Yet, intact wetlands play a key role as buffers in the hydrological cycle and as sinks for organic carbon, counteracting the effects of the increase in atmospheric CO2. Eight chapters comprising this volume of Aquatic Sciences analyze the current ecological situation and the use of the wetlands in major regions of the world in the context of global climate change. This final chapter provides a synthesis of the findings and recommendations for the sustainable use and protection of these important ecosystems. 相似文献
748.
In this paper, we analyze the effects of co-residence with elderly parents on gender differences in travel. The Household Responsibility Hypothesis (HRH) explains differences in the role of women regarding household responsibilities. However, research so far has studied “Western” household types while excluding households with co-residing elderly parents. Furthermore, research has paid exclusive attention to gender differences in commuting trips, and has neglected the effects of built environment characteristics. In view of these shortcomings, we pose the following research questions: what are the determinants of gendered differences in travel behavior, and specifically, what are the effects of elderly co-residence in households and land use on gender differences in trip frequency and travel distance? In addition to the HRH, we introduce the Elderly Co-residence Hypothesis, which suggests that co-residing elderly parents take over household responsibilities from adult women, resulting in diminishing gender differences in working-age travel patterns. We present the results of empirical research in Nanjing, China, that support this hypothesis. 相似文献
749.
750.