Topographic Context Research Articles

Holocene erosion at the summit of Ingleborough, Yorkshire Dales, northern England, indicated by cosmogenic 10 Be surface exposure dating

Summary Four gritstone outcrops around the summit rim of Ingleborough in the Yorkshire Dales, northern England, have yielded early to mid-Holocene cosmogenic 10 Be surface exposure ages, ranging from 10.61 ± 0.53 ka to 6.84 ± 0.35 ka. Taken at face value, the ages indicate that the outcrops became exposed to cosmic radiation at different times and consequently were not necessarily exposed as a result of the same single process at each site. Erosion of overlying gritstone debris during periods of climatic deterioration, during construction of a stone rampart, and during rock-slope failure may have all contributed to the exposure ages of these surfaces. Some of the ages may be compound in that a component of their isotope signal was acquired prior to the complete removal of the former debris cover. Although interpretation of the data set involves some speculation, the ages and topographic context of the samples indicate that the processes and timing of mountain top erosion may vary at small spatial scales.

Tissue-Specific Epigenetic Modifications in Root Apical Meristem Cells of Hordeum vulgare

Epigenetic modifications of chromatin structure are essential for many biological processes, including growth and reproduction. Patterns of DNA and histone modifications have recently been widely studied in many plant species, although there is virtually no data on the spatial and temporal distribution of epigenetic markers during plant development. Accordingly, we have used immunostaining techniques to investigate epigenetic modifications in the root apical meristem of Hordeum vulgare. Histone H4 acetylation (H4K5ac), histone H3 dimethylation (H3K4me2, H3K9me2) and DNA methylation (5mC) patterns were established for various root meristem tissues. Distinct levels of those modifications were visualised in the root cap, epidermis, cortex and vascular tissues. The lateral root cap cells seem to display the highest level of H3K9me2 and 5mC. In the epidermis, the highest level of 5mC and H3K9me2 was detected in the nuclei from the boundary of the proximal meristem and the elongation zone, while the vascular tissues were characterized by the highest level of H4K5ac. Some of the modified histones were also detectable in the cytoplasm in a highly tissue-specific manner. Immunolocalisation of epigenetic modifications of chromatin carried out in this way, on longitudinal or transverse sections, provides a unique topographic context within the organ, and will provide some answers to the significant biological question of tissue differentiation processes during root development in a monocotyledon plant species.

Planning Canberra's Memorial Landscape

Much has been written about Canberra and other modern, democratic capitals, in terms of how their urban designs communicate national identity and values. But relatively little research has focused specifically on the layout of their various commemorative works or the formal tools and processes used to manage these, except for the case of Washington DC. Commemorative planning decisions in Canberra are shaped by its unique historical, cultural, topographic and political context. Over the past century, Australia's federal government has developed a range of commemorative planning tools for Canberra, including physical master plans, formal open-space schemes and regulatory processes for individual memorial proposals. These tools have evolved in response to the developing constellation of built memorials and their scope of subject matter. Over the last decade, an expanding range of commemorative proposals from different interest groups and conflicting views as to their appropriateness has prompted the production of strategic guidelines for the capital, which pre-emptively suggest appropriate commemorative subjects, locations and forms and delineate the wider community values that memorial proposals should respect.

Are two elements better than one? Dual isotope‐ratio detrending of evaporative effects on lake carbonate paleoelevation proxies

Stable isotope‐based proxy methods enhance our ability to interpret geodynamical histories for tectonic provinces via paleoelevational reconstructions. These methods require that the unmodified isotopic composition of meteoric water is recorded by authigenic minerals, a critical assumption that has not been tested across wide‐ranging environmental and topographical contexts. Here, we show that Quaternary lake carbonateδ18O values are not strongly, nor significantly, correlated with regional elevation due to the isotopic modification of in‐flow waters following entry into the lake environment. These modifications are largely caused by surface water evaporation, and can result in >3 km errors in paleoelevation estimates if not accounted for. However, our analysis suggests that positive shifts in surface waterδ18O are accompanied by similar magnitude shifts in δ13C‐DIC. This positive co‐variation inδ18O and δ13C may be used to detrend lake carbonate compositions for the effects of surface water evaporation using a parameter we define here as the ‘13C‐excess’. When Tibetan lakes are excluded from the data set,13C‐excess values are significantly correlated with mean up‐slope hypsometric altitude with an error of ±500 m. Application of the13C‐excess approach to Cenozoic lake carbonate records from the western U.S. Cordillera both challenges and reinforces previous paleoelevational interpretations based onδ18O alone.

Charging the waters: the Grotte de Téthys as Versailles's initial metaphoric ground

Recent scholarly work has shifted our attention to the ways in which gardens negotiated the particularities of their ecological situation. New studies look at the archaeology of gardens, a fundamentally architectural shift which excavates issues of resource use. Materially specific research which sets gardens back into their hydraulic and topographic context has illuminated new dimensions of their inventive praxis. Many gardens turn out, in fact, to have been very carefully constructed in relation to a sensitive reading of local hydrological conditions. What is more, the facts of these sources seem also to be integrally enmeshed with their spatial and poetic aspects, providing salutary examples as our attention returns to what we are now calling sustainability.

Communities in stone: Translating from artefact clusters, topography and structure to cultures in the everyday in Jharkhand

It has always been difficult for archaeologists to transfer their impressions of any site to isolating and identifying communities that lived within these sites. All these problems were compounded when earlier archaeologists, while analyzing the personality of India, proclaimed that the Eastern Indian region was almost an ‘area of isolation’, or ‘terra incognita’. This meant that not much was known about the archaeology of these regions. Central, Southern, Western and Northern India have had large sites in the primary context which have been excavated. However, Eastern India had very few such sites (such as Paisra). In spite of the number of archaeological finds and comparing what is known of eastern India today with what is known of the rest of India, it may still be called ‘terra incognita’.Subsequent researches have proven the earlier analysis of the personality of India to some extent even while the answers to major issues remain tantalizingly out-of-reach. The Jharkhand region, hived from the earlier Bihar and the even earlier Bengal region, has become a mass of data, with many sites but few ideas regarding the communities that once lived there.Jharkhand is part of the Chotanagpur region, with its 600 m average height plateaus, bordered by a series of waterfalls and watered by a number of rivers. Almost 1300 sites dot the entire area of Bihar and the Chotanagpur region. They occur from all periods of time though very few of them are in the primary context. Most of the sites are surface finds and the context and embedding soil seems to have either worn away or not sufficiently able to give reliable results relating to dating. The region delivers its secrets very sparsely. None of the sites can be shown as a marker that may give us an idea of the entire region.This paper argues that the data cannot be interpreted in a unitary manner. The logic of the site/s may be seen from the fact that different communities/groups have been living in the region. They have not only had different cultures but the same group has had minor differences from region to region and different exploitative strategies in different seasons. This is why the clues left are seemingly so diverse and difficult to unravel. This paper explores the nature of these clues in their ecological and topographical contexts to illustrate this issue.

Modeling water availability for trees in tropical forests

Abstract Modeling soil water availability for tropical trees is a prerequisite to predicting the future impact of climate change on tropical forests. In this paper we develop a discrete-time deterministic water balance model adapted to tropical rainforest climates, and we validate it on a large dataset that includes micro-meteorological and soil parameters along a topographic gradient in a lowland forest of French Guiana. The model computes daily water fluxes (rainfall interception, drainage, tree transpiration and soil plus understorey evapotranspiration) and soil water content using three input variables: daily precipitation, potential evapotranspiration and solar radiation. A novel statistical approach is employed that uses Time Domain Reflectometer (TDR) soil moisture data to estimate water content at permanent wilting point and at field capacity, and root distribution. Inaccuracy of the TDR probes and other sources of uncertainty are taken into account by model calibration through a Bayesian framework. Model daily output includes relative extractable water, REW, i.e. the daily available water standardized by potential available water. The model succeeds in capturing temporal variations in REW regardless of topographic context. The low Root Mean Square Error of Predictions suggests that the model captures the most important drivers of soil water dynamics, i.e. water refilling and root water extraction. Our model thus provides a useful tool to explore the response of tropical forests to climate scenarios of changing rainfall regime and intensity.

Recent and future warm extreme events and high-mountain slope stability

The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored. We describe several large slope failures in rock and ice in recent years in Alaska, New Zealand and the European Alps, and analyse weather patterns in the days and weeks before the failures. Although we did not find one general temperature pattern, all the failures were preceded by unusually warm periods; some happened immediately after temperatures suddenly dropped to freezing. We assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed European Union programme ENSEMBLES for the central Swiss Alps. The models show an increase in the higher frequency of high-temperature events for the period 2001-2050 compared with a 1951-2000 reference period. Warm events lasting 5, 10 and 30 days are projected to increase by about 1.5-4 times by 2050 and in some models by up to 10 times. Warm extremes can trigger large landslides in temperature-sensitive high mountains by enhancing the production of water by melt of snow and ice, and by rapid thaw. Although these processes reduce slope strength, they must be considered within the local geological, glaciological and topographic context of a slope.

Francis‐Jones Morehen Thorp (FJMT)

AbstractThe output of FJMT varies greatly in scale and location. The practice has completed community schemes in Sydney's suburbs as well as accommodation for prestigious institutions in the city centre. It has adapted existing structures on heritage sites as well as producing high‐tech newbuilds. As Fleur Watson and Martyn Hook explain, what FJMT's projects have in common is an unwavering commitment to the enhancement of the public realm. The firm embraces the full responsibility of building in the sensitive urban and topographic context of this harbour city with its ridges and coastal inlets. Copyright © 2010 John Wiley & Sons, Ltd.

Wilhelm II's Weisser Saal and its Doppelthron

Kaiser Wilhelm II's refashioning of the principal diplomatic space within his Berlin palace was both a political and an architectural endeavour. In his radical transformation of the Weisser Saal or White Hall of the Berlin palace, Wilhelm expressed not only his dual identities as both German Emperor and King of Prussia, but also his fascination with the latest technology. Working with architect Ernst Ihne, Wilhelm created a Weisser Saal strikingly modern in its purity of volume and its conceptual use of architecture-as-lamp, critical aspects obscured by the hall's neo-baroque decorative programme. This analysis examines the political, architectural and topographical contexts in which the Kaiser conceived this space, a project that he initiated shortly after assuming the throne. The room's transformation lasted over half his reign and was one of Wilhelm's most expensive building projects. In conjunction with this endeavour, Wilhelm also fashioned a peculiar Doppelthron or double throne for the room, another attempt to express his dual titles. Designed to impart both dynastic and national legitimacy, Wilhelm's Weisser Saal and its double throne were however undermined by subtexts of impermanence, an irony that calls into question their ultimate efficacy as political acts.

Determining Titan surface topography from Cassini SAR data

A technique, referred to as SARTopo, has been developed for obtaining surface height estimates with 10 km horizontal resolution and 75 m vertical resolution of the surface of Titan along each Cassini Synthetic Aperture Radar (SAR) swath. We describe the technique and present maps of the co-located data sets. A global map and regional maps of Xanadu and the northern hemisphere hydrocarbon lakes district are included in the results. A strength of the technique is that it provides topographic information co-located with SAR imagery. Having a topographic context vastly improves the interpretability of the SAR imagery and is essential for understanding Titan. SARTopo is capable of estimating surface heights for most of the SAR-imaged surface of Titan. Currently nearly 30% of the surface is within 100 km of a SARTopo height profile. Other competing techniques provide orders of magnitude less coverage. We validate the SARTopo technique through comparison with known geomorphological features such as mountain ranges and craters, and by comparison with co-located nadir altimetry, including a 3000 km strip that had been observed by SAR a month earlier. In this area, the SARTopo and nadir altimetry data sets are co-located tightly (within 5–10 km for one 500 km section), have similar resolution, and as expected agree closely in surface height. Furthermore the region contains prominent high spatial resolution topography, so it provides an excellent test of the resolution and precision of both techniques.

First historical evidence of a significant Mt. Etna eruption in 1224

The 1224 Mt. Etna eruption is a significant event both in terms of the mass of erupted materials and because it involved the lower eastern slope of the volcano, reaching down to the sea. Nevertheless, it is unknown to current historical catalogues. According to the historical sources, only two other lava flows actually reached as far as the sea: in 396 BC, just north of the present-day inhabited area of Acireale, according to the geological data alone, and in 1669, when the lava covered the south-eastern flank of Mt. Etna and damaged Catania. We present and discuss the two medieval sources that attest to the eruption of 1224 and make available the original texts. Furthermore, through the close analysis of the historical and topographic context of the Etna area, taking account of the roads and ports in the early 13th century, we have tried to single out the possible area of the lava's outlet into the sea in 1224 on historical grounds. A repeat of an eruption similar to that of 1224 would have a serious impact today as the coast is densely populated.

Multi‐scale and multi‐criteria mapping of mountain peaks as fuzzy entities

Mountain peaks are mapped as multi‐scale entities with modifiable boundaries and variable contents. Four semantic meanings are imported and quantified to first characterize peaks at a range of spatial scales and then evaluate the multi‐criteria ‘peakness’ at each scale. Peakness is defined as the prototypicality of identified summits and as the similarity of each point (cell) to summits. The procedure then summarizes the individual‐scale peakness across considered spatial scales into a univariate membership surface. This allows mapping of vague peak entities as non‐homogeneous peak regions whose boundaries depend on user‐specified peakness thresholds. This procedure was applied in a case study to tackle several challenges in landform delineation, including boundary, spatial continuity, spatial scale, topographic context, and multi‐criteria definition.

New trends in digital terrain analysis: landform definition, representation, and classification

This article provides an ontological as well as methodological evaluation of recent progress in terrain analysis. It focuses on six topographic factors, or existences, that are important in characterizing the biophysical functions of topography: elevation, surface shape, topographic position, topographic context, spatial scale, and landform object. Terrain analysis approaches are assessed according to what they really deal with, as well as how they work. Important trends are consequently identified, in which spatial scale plays critical but non-uniform roles. An index-based approach to the compound function of multiple topographic existences is recognized as successful in modelling surface/subsurface moisture and mass movement potential, but not mountain temperature. A classification scheme categorises defined landforms in the literature according to the way they exist in human knowledge rather than their morphological properties and derivation methods. Five categories are outlined: bona fide objects, prototypical objects, fiat objects, landform classes, and multiscale objects. Peak object delineation is lastly assessed as an example demonstrating some of the recent trends in terrain analysis. Representations of higher-scale landscape context are identified to have great potential of linking vastly different spatial scales, as well as bridging field- versus object-based treatments of the terrain surface.

Static topographic modeling for facial expression recognition and analysis

Facial expression plays a key role in non-verbal face-to-face communication. It is a challenging task to develop an automatic facial expression reading and understanding system, especially, for recognizing the facial expression from a static image without any prior knowledge of the test subject. In this paper, we present a topographic modeling approach to recognize and analyze facial expression from single static images. The so-called topographic modeling is developed based on a novel facial expression descriptor, Topographic Context (TC), for representing and recognizing facial expressions. This proposed approach applies topographic analysis that treats the image as a 3D surface and labels each pixel by its terrain features. Topographic context captures the distribution of terrain labels in the expressive regions of a face. It characterizes the distinct facial expression while conserving abundant expression information and disregarding most individual characteristics. Experiments on person-dependent and person-independent facial expression recognition using two public databases (MMI and Cohn–Kanade database) show that TC is a good feature representation for recognizing basic prototypic expressions. Furthermore, we conduct the separability analysis of TC-based features by both a visualized dimensionality reduction example and a theoretical estimation using certain separability criterion. For an in-depth understanding of the recognition property of different expressions, the between-expression discriminability is also quantitatively evaluated using the separability criterion. Finally, we investigated the robustness of the extracted TC-based expression features in two aspects: the robustness to the distortion of detected face region and the robustness to different intensities of facial expressions. The experimental results show that our system achieved the best correct rate at 82.61% for the person-independent facial expression recognition.

Joining the Dots: Continuous Survey, Routine Practice and the Interpretation of a Cypriot Landscape

One of the major challenges facing intensive surface survey, even after some 30 years of development, is how to interpret surface artefact scatters in terms of past human activities and relationships. How can we combine the wealth of systematically collected survey data with the interpretative sophistication of contemporary landscape theory? This study uses web-based GIS and database technologies to provide a complete landscape data set and a fully integrated interpretative text carefully grounded in current landscape theory. The material comes from the Troodos Archaeological and Environmental Survey Project, which carried out intensive survey in the northern foothills of the Troodos Mountains in central Cyprus between 2000 and 2004. This survey covered all periods from the Neolithic to the present day, a wide range of topographical and environmental contexts, and a broad spectrum of disciplinary and interdisciplinary expertise. In this study we focus on some core themes, particularly the relationship between farming and mining, the control of production, and the spatial differentiation of human activity across the landscape. By interpreting the material traces of routine practices such as labour and subsistence, we attempt to reconstruct social landscapes of the past.

Quantifying the influence of topographic position on cougar (Puma concolor) movement in southern California, USA

AbstractLarge carnivores are frequently used as focal species for landscape‐level planning and conservation purposes. Information on cougars Puma concolor, for example, is being used to predict movement corridors and linkage areas in habitats influenced by rapid urbanization. However, animal movement through habitat terrain is a function of multiple factors, including complex topographic features. To assess the use of topographic position during movements by cougars in the Santa Ana Mountain Range of southern California, we analyzed the travel paths of 10–17 radio‐tagged individuals monitored during 44 overnight sessions. We examined selection for canyon bottom, gentle slope, steep slope and ridgeline topography at the scale of the movement session and at the scale of the home range. At both scales of selection, our results suggest that traveling or hunting cougars discriminated in their use of topographic position, that canyon bottoms and gentle slopes (<6°) ranked highest in compositional analyses of selection, and that these patterns were not highly confounded by the presence of preferred vegetation types. Ridgelines were used significantly less often than other positions. Our novel method of quantifying availability and use of topographic positions permits the assessment of terrain features, such as canyon bottoms, in facilitating cougar movements. For complex landscapes, models of animal movement should consider the topographic context that motivates patterns of habitat use, and should be developed using data obtained and analyzed at the appropriate spatial and temporal scales.

Glacier development and topographic context

AbstractThis paper analyses the topographic context of the remaining glaciated areas in the Maladeta Massif (Central Spanish Pyrenees). These ice‐covered surfaces have been incorporated into a geographic information system (GIS) in an attempt at correlating the presence of ice with a range of topographic variables obtained from a digital elevation model. The use of generalized additive models and binary regression tree models enabled us (i) to quantify the spatial variability in the distribution of glaciers attributable to characteristics of the local terrain, (ii) to investigate the interaction between the variables that account for the ice cover distribution and (iii) to map the probability of glacier development. Our results show that although the development of glaciers depends on regional climate conditions, the topographic context is of paramount importance in determining the location, extent, shape and recent evolution of each glacial body. Thus, the joint effect of altitude, exposure to incoming solar radiation, slope and mean curvature is able to explain more than 70 per cent of the observed variance. Copyright © 2006 John Wiley & Sons, Ltd.

The effects of habitat fragmentation due to forestry plantation establishment on the demography and genetic variation of a marsupial carnivore, Antechinus agilis

We conducted a demographic and genetic study to investigate the effects of fragmentation due to the establishment of an exotic softwood plantation on populations of a small marsupial carnivore, the agile antechinus ( Antechinus agilis), and the factors influencing the persistence of those populations in the fragmented habitat. The first aspect of the study was a descriptive analysis of patch occupancy and population size, in which we found a patch occupancy rate of 70% among 23 sites in the fragmented habitat compared to 100% among 48 sites with the same habitat characteristics in unfragmented habitat. Mark-recapture analyses yielded most-likely population size estimates of between 3 and 85 among the 16 occupied patches in the fragmented habitat. Hierarchical partitioning and model selection were used to identify geographic and habitat-related characteristics that influence patch occupancy and population size. Patch occupancy was primarily influenced by geographic isolation and habitat quality (vegetation basal area). The variance in population size among occupied sites was influenced primarily by forest type (dominant Eucalyptus species) and, to a lesser extent, by patch area and topographic context (gully sites had larger populations). A comparison of the sex ratios between the samples from the two habitat contexts revealed a significant deficiency of males in the fragmented habitat. We hypothesise that this is due to male-biased dispersal in an environment with increased dispersal-associated mortality. The population size and sex ratio data were incorporated into a simulation study to estimate the proportion of genetic diversity that would have been lost over the known timescale since fragmentation if the patch populations had been totally isolated. The observed difference in genetic diversity (gene diversity and allelic richness at microsatellite and mitochondrial markers) between 16 fragmented and 12 unfragmented sites was extremely low and inconsistent with the isolation of the patch populations. Our results show that although the remnant habitat patches comprise approximately 2% of the study area, they can support non-isolated populations. However, the distribution of agile antechinus populations in the fragmented system is dependent on habitat quality and patch connectivity.

Methodologies for analyzing intrinsic and required DEM accuracy for hydrological applications of flash floods

For extreme events like flash floods, infiltration is considered to be negligible, and the morphology of the watershed is considered to be the most significant factor. Thus, digital elevation models (DEMs) are the most efficient data source to define the catchment surface. To determine if the DEM is adapted, it is essential to analyze both the intrinsic accuracy and the required accuracy. In this paper we propose two complementary methodologies to analyze and evaluate these two kinds of DEM accuracy that relate to the hydrological applications to flash floods. The first methodology relates to the intrinsic accuracy: a diagnostic method analyzes the accuracy and stability of the extracted hydrographic network at catchment scale. To obtain correct positioning of the channels, results show the strong influence of the topographic context and the need for associating extra data on rivers, especially in flat areas. The impact of accuracy is evaluated through a scheme based on DEM grid rotation. A step by step and iterative process gives a fuzzy evaluation of the hydrographic network. These techniques also highlight the strong scale dependence of the extracted network. The second methodology relates to the required accuracy. To analyze the sensitivity to the DEM accuracy, we propose an approach by comparing the results of hydraulic models obtained from a "real" description of the river topography and from this description distorted by a numerical noise characterizing the lack of accuracy of the DEM. The impact of this noise on the overflows on the major bed is analyzed. The results show that the accuracy required by the thematicians is often greater than that strictly required by modeling, which opens interesting prospects to reduce the phases of data acquisition.