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This paper outlines a method for explicitly classifying landscape using 4 km2 grid cells, a set of attributes derived from topographic and geologic maps and an agglomerative numerical taxonomic procedure which can accommodate mixed data. The method was used to classify the landscapes of the Hunter Valley, NSW (22 000 km2) and the landscape classes generated are briefly described. These classes are compared with the land systems of the Hunter which were developed by traditional integrated survey procedure. It is concluded that the method could provide a more satisfactory starting-point for integrated land survey than air photo pattern analysis. 相似文献
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David Beresford-Jones Sean Taylor Clea Paine Alexander Pryor Jiří Svoboda Martin Jones 《Quaternary Science Reviews》2011,30(15-16):1948-1964
Precisely how Upper Palaeolithic human ecology was shaped by changing climate during the Pleniglacial remains a matter of debate, for while this generally cold period is now understood to include complex and often rapid flux in climate, there are still considerable difficulties in resolving climatic variations at particular times and places — derived from various lines of proxy evidence — with the high-resolution proxy record of temperature changes from oxygen isotope analysis of the Greenland ice-cores.In this paper we apply the methodology of large-scale flotation to newly excavated contexts from the Upper Palaeolithic (Gravettian) site of Dolní V?stonice II, Czech Republic, to explore the potential of charcoal — as a natural archive of environmental information — to offer information on environmental change towards the end of the middle pleniglacial during Oxygen Isotope Stage 3, between c. 32,500 and 31,200 Cal yr BP. The results of an analysis of ring widths and other anatomical features — interpreted alongside micromorphological data — indicate that this charcoal may capture a higher-resolution record of the changing climatic conditions during which humans were first expanding into these hitherto marginal ecologies and, consequently, shed new light upon the complexity of the lifeways that enabled them to do so. 相似文献
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Air pollution sources such as oil platforms and ships are sometimes located near coastlines where the plumes can impact population centers. Models of overwater dispersion must account for the stability of the overwater boundary layer. An overwater dispersion model based on the standard Gaussian formula is described which uses measurements of the air-sea temperature difference, the wind speed, and the mixing depth to predict concentration patterns at the coastline. Internal boundary layers and complex terrain at the coastline are accounted for. This new model is evaluated using the results of three tracer experiments in United States coastal zones. 相似文献
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Water conservation may be defined as a demonstrably beneficial reduction inthe amount of water of a certain quality for a specific use. Increasing costs as well as the risk of water shortages are likely to spur more efficient use of existing facilities. In many instances, conservation may be the most cost-effective way of increasing the supply of municipal water. Policymakers need to be familiar with the policy instruments, such as peak responsibility pricing, that could reduce the peak and average demands for municipal water and cost-effective technological options available to customers who wish to reduce water use. This paper is organized around these two themes and reviews the salient empirical findings in this field. Several municipalities have reduced peak demands, and the number of studies in demand management has increased substantially since the early 1960s. However, the interest in applying empirical findings has lagged behind research. Increasing costs are likely to stimulate innovative management and it is critical to explicate the problem and solutions so that policymakers would have the necessary understanding to make rational, cost-effective decisions. Time-and-location specific investigation is essential for enhancing such understanding. 相似文献
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This study presents the first measurement of 39Ar recoil ejection loss from individual, dimensionally characterized mineral grains due to neutron irradiation, and reveals the extent to which this recoil loss is problematic for 40Ar/39Ar dating. Using the well-characterized biotite standard GA1550, known to have between grain reproducibility of 40Ar*/39ArK of order 0.1%, we measured the thicknesses (3-210 μm) and surface areas (0.07-0.90 mm2) of 159 grains selected to span the dimensional range represented in the aliquot. Thinner grains with high surface area/volume (SA/V) reveal elevated 40Ar/39Ar, as much as 26% higher than thicker grains expected to suffer proportionately negligible depletion. Although the thinner grains yield intrinsically less precise measurements due to small 39Ar ion beams, a regular decrease in net recoil loss with increasing biotite grain thickness is clear for grains thinner than ca. 50 μm. Grains thicker than 50 μm reveal essentially no 39Ar loss within analytical uncertainties. The measured 39Ar loss spectrum is significantly higher than predicted by previous modeling approaches. These results suggest a practical threshold of ca. 50 μm grain thickness for biotites, and probably other phyllosilicates, irradiated with 235U fission spectrum neutrons in order to avoid recoil artifacts. Poor agreement between our data and simulation results indicates that recoil displacement models should be revisited in order to resolve the discrepancy. Further empirical work to determine the recoil loss of 39Ar in other minerals is important not only for routine age measurements, but also to shed more light on the role of recoil in multi-diffusion domain theory and other thermochronologic applications exploiting variable diffusion radii and/or grain size effects. 相似文献
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