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U.S. geomorphologists and biogeographers often cite early theoretical roots dating back to late nineteenth- and early twentieth-century exemplars such as Powell, Gilbert, Cowles, and Clements, or earlier European contributors like Hutton, Lyell, von Humboldt, and, of course, Darwin. Yet reviews of our intellectual roots often overlook an early and important U.S. contributor: George Perkins Marsh. Marsh's work on Man and Nature is more often cited in the field of environmental history, where it is appropriately noted as a prescient review of human impacts on the landscape. We suggest, however, that his significance extends beyond early environmental activism and that in fact Marsh describes many concepts and analytical approaches that continue to underlie modern geomorphology and biogeography. Moreover, Marsh's ideas and approach presaged fundamental concepts central to our current study of the Anthropocene and coupled human–environment systems, as he emphasized interconnections among biotic, geomorphic and human elements, perhaps most notably with regard to impacts of deforestation on flood regimes. There is, therefore, much to learn from Marsh—both about early thinking in physical geography and about the depth of scientific analysis underlying our discipline's early interest in human impacts. [ABSTRACT FROM AUTHOR]

Between 1870 and 1920, the United States government produced a series of Statistical Atlases, representing the country's first attempts to provide a fully national perspective on its rapidly evolving physical and human geographies. Compiled once every 10 years using data from the U.S. Census and other sources, the Statistical Atlases offer views of the country during a time of significant national expansion. The last decades of the nineteenth century saw a dramatic rise in numerous demographic measures, including population, immigration, industrialization, and urbanization. The publications illustrate how their creators viewed this national expansion as it unfolded. [ABSTRACT FROM AUTHOR]

To meet rising demands for climate-literate workers, undergraduate courses and curricula will require updates so that students are afforded opportunities to engage in climate science education. Previous research on undergraduate climate education has primarily focused on evaluating whether students have grounding in essential climate science principles, but these studies fail to capture the degree to which students feel they are exposed to climate education in their undergraduate programs and courses. In this study, we characterize recent trends in undergraduates' perceived exposure to climate education across the U.S. by analyzing responses to a national survey of graduate students who attended undergraduate institutions in the U.S. (n = 423). Survey respondents scored the levels of exposure that they received to a variety of climatological topics during their undergraduate studies, which ranged from applied (e.g., earth observations, numerical modeling) to interdisciplinary (e.g., agricultural climatology, hydroclimatology) and specialized (e.g., boundary-layer climatology). Our results reveal that those who received bachelor's degrees from programs related to human dimensions of natural resources management (e.g., geography, resource economics) generally felt that their undergraduate curricula provided them with exposure to climate education, whereas those who graduated from programs in engineering and the agricultural and life sciences largely reported a lack of climate coverage in their undergraduate studies. Students of all disciplinary backgrounds indicated that they received poor exposure to numerical modeling of historical and future climatic conditions. Findings from this study underline key areas in which curricular or course improvements are needed to ensure that future decision-makers are confident in their practical use of climate science. [ABSTRACT FROM AUTHOR]

Coastal wetland responses to sea-level rise are greatly influenced by biogeomorphic processes that affect wetland surface elevation. Small changes in elevation relative to sea level can lead to comparatively large changes in ecosystem structure, function, and stability. The surface elevation table-marker horizon (SET-MH) approach is being used globally to quantify the relative contributions of processes affecting wetland elevation change. Historically, SET-MH measurements have been obtained at local scales to address site-specific research questions. However, in the face of accelerated sea-level rise, there is an increasing need for elevation change network data that can be incorporated into regional ecological models and vulnerability assessments. In particular, there is a need for long-term, high-temporal resolution data that are strategically distributed across ecologically-relevant abiotic gradients. Here, we quantify the distribution of SET-MH stations along the northern Gulf of Mexico coast (USA) across political boundaries (states), wetland habitats, and ecologically-relevant abiotic gradients (i.e., gradients in temperature, precipitation, elevation, and relative sea-level rise). Our analyses identify areas with high SET-MH station densities as well as areas with notable gaps. Salt marshes, intermediate elevations, and colder areas with high rainfall have a high number of stations, while salt flat ecosystems, certain elevation zones, the mangrove-marsh ecotone, and hypersaline coastal areas with low rainfall have fewer stations. Due to rapid rates of wetland loss and relative sea-level rise, the state of Louisiana has the most extensive SET-MH station network in the region, and we provide several recent examples where data from Louisiana’s network have been used to assess and compare wetland vulnerability to sea-level rise. Our findings represent the first attempt to examine spatial gaps in SET-MH coverage across abiotic gradients. Our analyses can be used to transform a broadly disseminated and unplanned collection of SET-MH stations into a coordinated and strategic regional network. This regional network would provide data for predicting and preparing for the responses of coastal wetlands to accelerated sea-level rise and other aspects of global change. [ABSTRACT FROM AUTHOR]

This project involved the construction of a surficial (Quaternary) geologic map of part of McLean County, Illinois. The Saybrook 7.5-minute Quadrangle (scale 1:24,000) was the focus area. The quadrangle largely covers rural agricultural land, but also contains the small town of Saybrook. Multiple, major episodes of glaciation over the past 1,200,000 years have controlled the regional geologic history. The most recent (Wisconsin Episode) glaciation almost exclusively shaped the observed surficial geologic and geomorphic features in the quadrangle. Field observations, USDA soil survey data, private water well data, sparse stratigraphic borehole information, and LIDAR elevation data were used to construct the map. Computational methodologies included ACD Systems Canvas™ and Adobe Acrobat™ software. The surficial geologic map includes four lithostratigraphic units. In stratigraphic order (from oldest to youngest) are the Delavan Member, Tiskilwa Formation, Batestown Member, Lemont Formation, Henry Formation, and Cahokia Formation. [ABSTRACT FROM PUBLISHER]

The Elwha River restoration project, in Washington State, includes the largest dam-removal project in United States history to date. Starting September 2011, two nearly century-old dams that collectively contained 21 ± 3 million m 3 of sediment were removed over the course of three years with a top-down deconstruction strategy designed to meter the release of a portion of the dam-trapped sediment. Gauging with sediment-surrogate technologies during the first two years downstream from the project measured 8,200,000 ± 3,400,000 tonnes of transported sediment, with 1,100,000 and 7,100,000 t moving in years 1 and 2, respectively, representing 3 and 20 times the Elwha River annual sediment load of 340,000 ± 80,000 t/y. During the study period, the discharge in the Elwha River was greater than normal (107% in year 1 and 108% in year 2); however, the magnitudes of the peak-flow events during the study period were relatively benign with the largest discharge of 292 m 3 /s (73% of the 2-year annual peak-flow event) early in the project when both extant reservoirs still retained sediment. Despite the muted peak flows, sediment transport was large, with measured suspended-sediment concentrations during the study period ranging from 44 to 16,300 mg/L and gauged bedload transport as large as 24,700 t/d. Five distinct sediment-release periods were identified when sediment loads were notably increased (when lateral erosion in the former reservoirs was active) or reduced (when reservoir retention or seasonal low flows and cessation of lateral erosion reduced sediment transport). Total suspended-sediment load was 930,000 t in year 1 and 5,400,000 t in year 2. Of the total 6,300,000 ± 3,200,000 t of suspended-sediment load, 3,400,000 t consisted of silt and clay and 2,900,000 t was sand. Gauged bedload on the lower Elwha River in year 2 of the project was 450,000 ± 360,000 t. Bedload was not quantified in year 1, but qualitative observations using bedload-surrogate instruments indicated detectable bedload starting just after full removal of the downstream dam. Using comparative studies from other sediment-laden rivers, the total ungauged fraction of < 2-mm bedload was estimated to be on the order of 1.5 Mt. [ABSTRACT FROM AUTHOR]

• Spatial analysis model was used to compare the spatial distribution of protected river areas in China and the United States. • The distribution characteristics were explored in combination with physical geography zoning and ecological zoning, etc. • Discover the diversity in society, protection systems and governance methods behind the differences in spatial distribution. The National Water Park System (NWPS) in China and the National Wild and Scenic Rivers System (NWSRS) in the United States represent typical protected river systems (PRSs) for conservation of water resources. This study used spatial analysis methods to characterize and compare the aggregated distribution of two types of PRSs and further explored the reasons for their differences in spatial distribution. The results showed that the highest concentrations of National Water Parks (NWPs) were along the east coast and adjacent central areas, accounting for 69.48% of all 878 units, and 59.45% of the NWPs were concentrated in the plain area characterized by a high temperature, high humidity and high nighttime light. The spatial distribution of NWPs was positively correlated with altitude, drainage density, population density, GDP/km2, and dam density in each province, while not correlated with forest coverage. In contrast, National Wild and Scenic Rivers (NWSRs) were concentrated along west coasts areas, accounting for 56.88% of all 218 units, and 78.84% of NWSRs were concentrated in mountainous areas near coastlines, characterized by a high humidity and low nighttime light. The spatial distribution of NWSRs in each state was positively correlated with areas of high forest coverage, while negatively related to altitude. There was no correlation between the NWSRs distribution with population density, GDP/km2, dam density and drainage density. The differences in spatial distribution and driving factors of protected rivers (PRs) between the two countries reflected their differences in conservation objectives, ideology, and governance system of protected areas. [ABSTRACT FROM AUTHOR]

US national parks are challenged by climate and other forms of broad-scale environmental change that operate beyond administrative boundaries and in some instances are occurring at especially rapid rates. Here, we evaluate the climate change exposure of 289 natural resource parks administered by the US National Park Service (NPS), and ask which are presently (past 10 to 30 years) experiencing extreme (<5th percentile or >95th percentile) climates relative to their 1901–2012 historical range of variability (HRV). We consider parks in a landscape context (including surrounding 30 km) and evaluate both mean and inter-annual variation in 25 biologically relevant climate variables related to temperature, precipitation, frost and wet day frequencies, vapor pressure, cloud cover, and seasonality. We also consider sensitivity of findings to the moving time window of analysis (10, 20, and 30 year windows). Results show that parks are overwhelmingly at the extreme warm end of historical temperature distributions and this is true for several variables (e.g., annual mean temperature, minimum temperature of the coldest month, mean temperature of the warmest quarter). Precipitation and other moisture patterns are geographically more heterogeneous across parks and show greater variation among variables. Across climate variables, recent inter-annual variation is generally well within the range of variability observed since 1901. Moving window size has a measureable effect on these estimates, but parks with extreme climates also tend to exhibit low sensitivity to the time window of analysis. We highlight particular parks that illustrate different extremes and may facilitate understanding responses of park resources to ongoing climate change. We conclude with discussion of how results relate to anticipated future changes in climate, as well as how they can inform NPS and neighboring land management and planning in a new era of change. [ABSTRACT FROM AUTHOR]

Abstract: In a short communication, Huang et al. (2013) presented arguments for invalidating the expanded Lane's relation that we proposed in Dust and Wohl (2012) and reproposed their approach for modifying the balance schematic of the Lane's relation that they first proposed in Nanson and Huang (2008). We contend that their arguments do not invalidate any aspect of the expanded Lane's relation that we proposed and find, conversely, key aspects of their proposed alternative approach problematic. We provide detailed counter arguments for their key points regarding our proposed expanded Lane's relation and for their proposed alternative approach. [Copyright &y& Elsevier]

Abstract: As population and water demand have grown, U.S. cities have responded by expanding their water supplies. This article traces this process over a century for ten U.S. cities. Most of the cities began by providing inexpensive local ground water. As the renewable supply capacity of local sources was exceeded, cities were forced to look further afield to obtain (or purchase) water (e.g., Marion, IL; Greensboro, NC), to access water from Federal projects (Tucson, AZ) or through international or interstate agreements (Waukesha, WI and Virginia Beach, VA), to combine with other localities in large joint projects (Greensboro, NC), or to use eminent domain to annex land for a new reservoir. This last approach has become increasingly limited by environmental statutes. The purchasing of water from other systems (Greensboro, NC) or water rights ( Tucson, AZ), aquifer storage and recovery systems (Tucson, AZ, Wichita, KS), and reclaiming wastewater for use in non-potable landscaping (Alamogordo, NM; Lubbock, TX; Tucson, AZ) are the more expensive options that cities are increasingly utilizing. Desalination represents the end of this process – expensive, but with a potential for enormous supply expansion that exceeds all likely demands. Demand management measures come into play only when the cost of securing additional water begins to exceed the cost of conservation or is induced by law. Reservoirs, well-fields, desalination plants, aquifer storage and recovery systems, and inter-basin water purchases have been abandoned because of the restrictions imposed by environmental laws or because less expensive demand-side options have been identified. The relationship between city size and its progression through these increasingly expensive water supply options is determined by local water resource endowments as determined by legal considerations and its physical geographic setting. [Copyright &y& Elsevier]

Local and regional-scale knowledge of climate change is needed to model ecosystem responses, assess vulnerabilities and devise effective adaptation strategies. High-resolution gridded historical climate (GHC) products address this need, but come with multiple sources of uncertainty that are typically not well understood by data users. To better understand this uncertainty in a region with a complex climatology, we conducted a ground-truthing analysis of two 4 km GHC temperature products (PRISM and NRCC) for the US Northeast using 51 Cooperative Network (COOP) weather stations utilized by both GHC products. We estimated GHC prediction error for monthly temperature means and trends (1980–2009) across the US Northeast and evaluated any landscape effects (e.g., elevation, distance from coast) on those prediction errors. Results indicated that station-based prediction errors for the two GHC products were similar in magnitude, but on average, the NRCC product predicted cooler than observed temperature means and trends, while PRISM was cooler for means and warmer for trends. We found no evidence for systematic sources of uncertainty across the US Northeast, although errors were largest at high elevations. Errors in the coarse-scale (4 km) digital elevation models used by each product were correlated with temperature prediction errors, more so for NRCC than PRISM. In summary, uncertainty in spatial climate data has many sources and we recommend that data users develop an understanding of uncertainty at the appropriate scales for their purposes. To this end, we demonstrate a simple method for utilizing weather stations to assess local GHC uncertainty and inform decisions among alternative GHC products. [ABSTRACT FROM AUTHOR]

Abstract: We perform the first long-term (>1 year) continuous adjoint simulations with a global atmospheric chemistry–transport model focusing on population exposure to fine particulate matter (PM2.5) and associated risk of early death. Sensitivities relevant to intercontinental and high-altitude PM pollution are calculated with particular application to aircraft emissions. Specifically, the sensitivities of premature mortality risk in different regions to NO x , SO x , CO, VOC and primary PM2.5 emissions as a function of location are computed. We apply the resultant sensitivity matrices to aircraft emissions, finding that NO x emissions are responsible for 93% of population exposure to aircraft-attributable PM2.5. Aircraft NO x accounts for all of aircraft-attributable nitrate exposure (as expected) and 53% of aircraft-attributable sulfate exposure due to the strong “oxidative coupling” between aircraft NO x emissions and non-aviation SO2 emissions in terms of sulfate formation. Of the health risk-weighted human PM2.5 exposure attributable to aviation, 73% occurs in Asia, followed by 18% in Europe. 95% of the air quality impacts of aircraft emissions in the US are incurred outside the US. We also assess the impact of uncertainty or changes in (non-aviation) ammonia emissions on aviation-attributable PM2.5 exposure by calculating second-order sensitivities. We note the potential application of the sensitivity matrices as a rapid policy analysis tool in aviation environmental policy contexts. [Copyright &y& Elsevier]

Abstract: Some states are defining environmental justice areas geographically on the basis of demographic criteria alone. This is problematic as it does not consider distributive concentrations of environmental toxins. Although environmental justice is much more than avoiding concentrations of increased environmental risk, the identification of such areas could provide states with a roadmap for addressing concentrations and for the facilitation of appropriate community-targeted programs in response. This research proposes an applied quantitative approach for the geographic designation of areas determined to be at greater relative risk of exposure to environmental toxins as part of states'' broader environmental justice goals and policies. Using the U.S. Environmental Protection Agency''s Risk Screening Environmental Impact Tool (RSEI) and spatial analyses, the proposed method defines geographic areas reflecting calculated risk values pertaining to exposed populations and toxic releases. The method is applied to four counties of New York, and the results are juxtaposed with current state-declared environmental justice areas, which are defined on demography alone. This approach permits geospatial mapping and exploratory spatial data analysis. The method potentially can be used by states to effectively address concentrations of toxic releases as part of their environmental justice programs and policies. [Copyright &y& Elsevier]

Human mortality exhibits a strong seasonal pattern with deaths in winter far exceeding those in the summer. While the pattern itself is clear, there have been very few studies examining whether the magnitude or timing of seasonal mortality varies considerably across space. Thus, the goal of this study is to conduct a comprehensive geographic analysis of seasonal mortality across the United States and to uncover systematic regional differences in such mortality. Unique seasonal mortality curves were created for 28 metropolitan statistical areas across the United States, and the amplitude and timing of mortality peaks were determined. The findings here indicate that the seasonality of mortality exhibits strong spatial variation with the largest seasonal mortality amplitudes found in the southwestern United States and the smallest in the North, along with South Florida. In addition, there were strong intra-regional similarities that exist among the examined cities, implying that environmental factors are more important than social factors in determining seasonal mortality response. This work begins to fill a large gap within the scientific literature concerning the geographic variation and underlying causes of seasonal mortality across the United States. [ABSTRACT FROM AUTHOR]

The global trade of goods is associated with a virtual transfer of the water required for their production. The way changes in trade affect the virtual redistribution of freshwater resources has been recently documented through the analysis of the virtual water network. It is, however, unclear how these changes are contributed by different types of products and regions of the world. Here we show how the global patterns of virtual water transport are contributed by the trade of different commodity types, including plant, animal, luxury (e.g., coffee, tea, and alcohol), and other products. Major contributors to the virtual water network exhibit different trade patterns with regard to these commodity types. The net importers rely on the supply of virtual water from a small percentage of the global population. However, discrepancies exist among the different commodity networks. While the total virtual water flux through the network has increased between 1986 and 2010, the proportions associated with the four commodity groups have remained relatively stable. However, some of the major players have shown significant changes in the virtual water imports and exports associated with those commodity groups. For instance, China has switched from being a net exporter of virtual water associated with other products (non-edible plant and animal products typically used for manufacturing) to being the largest importer, accounting for 31% of the total water virtually transported with these products. Conversely, in the case of The United states of America, the commodity proportions have remained overall unchanged throughout the study period: the virtual water exports from The United States of America are dominated by plant products, whereas the imports are comprised mainly of animal and luxury products. [ABSTRACT FROM AUTHOR]

River restoration as a science needs to balance numerical analysis with a more general systems understanding typical of a classification-based approach. We show the need for this balance by comparing the Davis–Gilbert debate in physical geography to the current ‘Rosgen wars' (Lave, 2008) in fluvial geomorphology and river restoration. In both controversies, one perspective was accepted for a period of time, but then subsequently vilified by vocal members of the discipline. However, in the process of replacing one paradigm with another, former viewpoints are often misrepresented and set up as contradictory to the newer paradigm. Careful reconsideration of Gilbert’s and Davis' approaches to geomorphology shows them not as mutually exclusive, but rather as complementary. Observation and nomenclature, as well as measurement and process analysis, are not only parts of the general temporal progression of a discipline, but are complementary scientific approaches. Davis' nomenclature and Gilbert’s analytical processes are both necessary to understand and discuss landscape geomorphology. Similarly, both Rosgen’s classification system, or one like it, and other more analytical, process-based examinations, are necessary for a comprehensive approach to river restoration. It is clear that multiple viewpoints and approaches triangulate towards a more thorough understanding of a system and will increase the probability of successful restoration. This will most likely include system-wide observation and classification married to numerical process modeling. [ABSTRACT FROM AUTHOR]

Bacteria from the genus Polaromonas are dominant phylotypes in clone libraries and culture collections from polar and high-elevation environments. Although Polaromonas has been found on six continents, we do not know if the same phylotypes exist in all locations or if they exhibit genetic isolation by distance patterns. To examine their biogeographic distribution, we analyzed all available, long-read 16S rRNA gene sequences of Polaromonas phylotypes from glacial and periglacial environments across the globe. Using genetic isolation by geographic distance analyses, including Mantel tests and Mantel correlograms, we found that Polaromonas phylotypes are globally distributed showing weak isolation by distance patterns at global scales. More focused analyses using discrete, equally sampled distances classes, revealed that only two distance classes (out of 12 total) showed significant spatial structuring. Overall, our analyses show that most Polaromonas phylotypes are truly globally distributed, but that some, as yet unknown, environmental variable may be selecting for unique phylotypes at a minority of our global sites. Analyses of aerobiological and genomic data suggest that Polaromonas phylotypes are globally distributed as dormant cells through high-elevation air currents; Polaromonas phylotypes are common in air and snow samples from high altitudes, and a glacial-ice metagenome and the two sequenced Polaromonas genomes contain the gene hipA, suggesting that Polaromonas can form dormant cells. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze the evolution of geography in the United States' K-12 education system throughout the Nineteenth Century to understand the causes of variations, shifts in focus, and relative importance placed on geography. A broad theoretical framework, based on the work of sociologists of education and education philosophers and historians, guided the process of data collection and analysis. The authors feel that this research is significant because it clearly shows that geography was a high-status, 'stand alone' subject in the public schools throughout most of the Nineteenth Century. Factors contributing to geography's prominent curricular position correlate well with the theoretical notion that the variation of emphasis of school subjects hinges largely on the involvement of their respective academic disciplines and/or scholars, and that society must perceive the subject as macro-economically beneficial to the long-term longevity of the nation's interests and economy. For the social studies as a whole, this paper represents a model of analysis for all of the subject areas that are currently included in the collection of ideas, themes, and approaches that comprise the modern concept of the social studies. [ABSTRACT FROM AUTHOR]

U-Pb age spectra of detrital zircons in samples from the Paleogene Colton Formation in the Uinta Basin of northeastern Utah and the Late Cretaceous McCoy Mountains Formation of southwestern Arizona (United States) are statistically indistinguishable. This finding refutes previous inferences that arkosic detritus of the Colton was derived from cratonic basement exposed by Laramide tectonism, and instead establishes the Cordilleran magmatic arc (which also provided sediment to the McCoy Mountains Formation) as the primary source. Given the existence of a north-south-trending drainage divide in eastern Nevada and the north-northeast direction of Laramide paleoflow throughout Arizona and southern Utah, we infer that a large river system headed in the arc of the Mojave region fl owed northeast ∼700 km to the Uinta Basin. Named after its source area, this Paleogene California River would have been equal in scale but opposite in direction to the modern Green River-Colorado River system, and the timing and causes of the subsequent drainage reversal are important constraints on the tectonic evolution of the Cordillera and the Colorado Plateau. [ABSTRACT FROM AUTHOR]

Abstract: MODIS (Moderate Resolution Imaging Spectroradiometer) snow cover products, of daily, freely available, worldwide spatial extent at medium spatial resolution, have been widely applied in regional snow cover and modeling studies, although high cloud obscuration remains a concern in some applications. In this study, various approaches including daily combination, adjacent temporal deduction, fixed-day combination, flexible multi-day combination, and multi-sensor combination are assessed to remove cloud obscuration while still maintain the temporal and spatial resolutions. The performance of the resultant snow cover maps are quantitatively evaluated against in situ observations at 244 SNOTEL stations over the Pacific Northwest USA during the period of 2006–2008 hydrological years. Results indicate that daily Terra and Aqua MODIS combination and adjacent temporal deduction can reduce cloud obscuration and classification errors although an annual mean of 37% cloud coverage remains. Classification errors in snow-covered months are actually small and tend to underestimate the snow cover. Primary errors of MODIS daily, fixed and flexible multi-day combination products occur during transient months. Flexible multi-day combination is an efficient approach to maintain the balance between temporal resolution and realistic estimation of snow cover extent since it uses two thresholds to control the combination processes. Multi-sensor combinations (daily or multi-day), taking advantage of MODIS high spatial resolution and AMSR-E cloud penetration ability, provide cloud-free products but bring larger image underestimation errors as compared with their MODIS counterparts. [Copyright &y& Elsevier]

An edge extraction model has been developed that uses multitemporal satellite synthetic aperture radar data to delineate shorelines in estuaries. Using Japanese ALOS PALSAR HH data acquired in December 2006 and JERS-1 L-HH SAR data in December 1994, we mapped shorelines of the outer Pamlico Peninsula, Dare County, North Carolina, USA, spanning 12 years. To assess the validity and accuracy of the delineation, we compared (a) 1994 shorelines versus those derived from the 1993 digital orthophotographs, and (b) 2006 shorelines versus field data collected in February 2007. With promising results, we then analysed and quantified the shoreline changes between 1994 and 2006 on the north, east, and south sides of the Peninsula. Virtually no discernible changes on the north and south sides were found. However, significant landward migration in the middle to southern portion on the east shore was observed. Spatial retreat of shorelines varied greatly, with the maximum rate averaged over a span of 12 years exceeding 11 m year-1. The results support further monitoring of shorelines in estuaries using active remote sensing and the potential for the methodology developed to identify erosional hotspots. [ABSTRACT FROM AUTHOR]

The article focuses on the early contributions to arid-zone hydrogeology in the eastern Basin and Range region. It presents a physical geography of Basin and Range (B&R) province of West America as the main core of major improvements in arid-zone hydrogeology after the Civil War. Moreover, it cites the development of geology-based conceptual models of intermontane basin, river valley, and mountain block underground bed in the eastern B&R region through 1945. It also presents an overview of a series of brief statements regarding the pioneering contributions of individuals and institutions with string regional ties, especially on studies that focuses on geologic and hydrogeochemistry.

Rock varnish from late to latest Pleistocene geomorphic features in the drylands of the western U.S. provides evidence of nine millennial-scale wet events from 11,500-18,000 calendar yr B.P., represented by regionally replicable and approximately evenly spaced manganeseand barium-rich dark bands in varnish microstratigraphy. Preliminary radiometric age calibration indicates that these events appear to be broadly coeval with millennial-scale cooling events identified in the Greenland Ice Sheet Project 2 (GISP2) ice core record. Six of these wet events are associated with the cold intervals of the Younger Dryas and Heinrich event H1, and the other three with the short-lived cooling phases of the Intra-Allerød Cold Period, the Older Dryas, and the Oldest Dryas. These results, combined with our previous documentation of millennial-scale wet events in the Holocene varnish record for the same region, indicate that such wet oscillations in the western U.S. may be parts of regionally widespread manifestation of well-documented, pervasive millennial-scale cycles of the North Atlantic climate. [ABSTRACT FROM AUTHOR]

The development of the National Lightning Detection Network (NLDN) can be traced from the initial funding by the Electric Power Research Institute in June 1983. This support, when coupled with a small National Science Foundation-sponsored research program at the State University of New York at Albany, would lead in just six years to the coverage of 48 states by a network of lightning detectors providing the location and physical characteristics of nearly all cloud-to-ground lightning flashes in the continental United States. The generous sharing of data from existing federal lightning detection networks provided one-third of this national coverage. The measured lightning characteristics included stroke location to an accuracy of roughly 2 km, polarity and peak current estimates, and flash multiplicity or number of strokes within the flash. The development of satellite communications during this period ensured the receipt of data and the transmission of flash characteristics to consumers in the university, government, and private sectors. The history of the NLDN development is a story driven by technology with its roots in the 1970s. The future of lightning detection is embodied within the current satellite plans for a Geostationary Lightning Mapper to observe total lightning in the Western Hemisphere as part of the Geostationary Operational Environmental Satellite-R (GOESR) program, with launch dates as early as 2014. [ABSTRACT FROM AUTHOR]

Geophysical and drill-hole data within the Reelfoot rift of Arkansas, Tennessee, Missouri, and Kentucky, USA, were integrated to create a structure contour map and threedimensional computer model of the top of the Precambrian crystalline basement. The basement map and model clearly define the northeast- trending Cambrian Reelfoot rift, which is crosscut by southeast-trending basement faults. The Reelfoot rift consists of two major basins, separated by an intrarift uplift, that are further subdivided into eight subbasins bound by northeast- and southeast-striking rift faults. The rift is bound to the south by the White River fault zone and to the north by the Reelfoot normal fault. The modern Reelfoot thrust fault, responsible for most of the New Madrid seismic zone earthquakes, is interpreted as an inverted basement normal fault. Geologic interpretation of 5077 shallow borings in the central Mississippi River valley enabled the construction of a structure contour map of the Pliocene-Pleistocene unconformity (top of the Eocene-base of Mississippi River alluvium) that overlies most of the Reelfoot rift. This map reveals both river erosion and tectonic deformation. Deformation of the Pliocene-Pleistocene unconformity appears to be controlled by the northeast- and southeast-trending basement faults. The northeast-trending rift faults have undergone and continue to undergo Quaternary dextral transpression. This has resulted in displacement of two major rift blocks and formation of the Lake County uplift, Joiner ridge, and the southern half of Crowley's Ridge as compressional stepover zones that appear to have originated above basement fault intersections. The Lake County uplift has been tectonically active over the past ~2400 yr and corresponds with a major segment of the New Madrid seismic zone. The aseismic Joiner ridge and the southern portion of Crowley's Ridge may reflect earlier uplift, thus indicating Quaternary strain migration within the Reelfoot rift. [ABSTRACT FROM AUTHOR]

Abstract: Statistical analysis of rock glaciers in the Lemhi Range demonstrates that their development and preservation is controlled primarily by annual insolation and lithology. We inspected 171 alpine valleys in the Lemhi Range using optical remote sensing techniques, digital topographic analysis, and field examination. In those valleys, we identified 48 rock glaciers and examined them for lichen cover, evidence of ice presence, specific evidence of movement, and distinctive morphological features. In addition to recording the presence or absence of a rock glacier in each alpine valley, existing rock glaciers were classified according to their morphology. Factors such as topographic shading, lithology, relief, aspect, and elevation determine the development and preservation of rock glaciers. Analysis of these factors in the Lemhi Range shows that elevation >2600 m, a north-facing aspect (300–60°), and <2300 h of direct sunlight per year are necessary conditions for the existence of rock glaciers in any form. The majority of alpine valleys in the Lemhi Range meet these requirements. Thus, other parameters, including topographic shading and lithology, must determine occurrence of rock glaciers in the Lemhi Range. Multivariate statistical analysis of controlling parameters demonstrates that annual insolation and latitude influence rock glacier occurrence most strongly. Whereas duration of insolation is a logical controlling factor, latitude is more enigmatic. Additional statistical analysis indicates that the latitude factor is likely a reflection of lithologic changes with latitude along the range. Lithology may affect rock glacier distribution through its effects on hydrology or air ventilation. Moreover, statistical analysis shows that rock glacier occurrence correlates with protalus lobe occurrence, suggesting that protalus lobes play a role in the genesis of rock glaciers in the Lemhi Range. Separate analysis of the classification systems shows that each morphologic class, inferred to correlate with rock glacier activity, is statistically significant and distinguishable from other classes. In addition to the effect of insolation, statistical analysis of the classification system also shows that latitude influences distribution of existing rock glacier classes independent of lithology. [Copyright &y& Elsevier]

Abstract: The Ratcliff Site in southwestern Virginia lies in a small second-order stream valley filled with approximately 3.5 m of organic-rich deposits that contain bones of mammoth, mastodon, deer (or antelope), logs, and plant macrofossils. Radiocarbon analyses indicate the age of the organic-rich sediment ranges from >44,000 to 29,100 14C yr BP, a time period with no fossil remains reported in this region of the Appalachians. Analyses of field observations, textural data, organic carbon content, and plant macrofossils indicate that the organic-rich sediments contain interbedded standing-water and debris-flow deposits. Up to 6 m of oxidized debris-flow sediments bury the organic-rich sediments. The presence of Rubus parviflorus (Thimble Berry) throughout the deposit indicates the site had a boreal environment from >44,000 to 29,100 14C yr BP. Plant macrofossil evidence indicates the uplands had stands of spruce/jack-pine forests while the valley contained ponds and associated wetlands. Three debris flows occurred at the site between approximately 38,000 and 29,000 14C yr BP, suggesting a recurrence interval for major storms of approximately 3000 yr, even though the apparent stability of the boreal environment implies a climate not conducive to catastrophic rainstorms. This conflicting combination of features suggests that during the middle Wisconsinan this area experienced generally cool climates, dominated by polar air masses, but was punctuated by relatively brief warm periods marked by incursions of tropical air masses. [Copyright &y& Elsevier]

In 1975 E. H. Rapoport described a pattern of increasing latitudinal range sizes for organisms with increasing latitude, a pattern that is now known as Rapoport's rule. The universal applicability of Rapoport's rule has been long contested, making it one of the more controversial biogeographic “rules.” This study aims to reassess the applicability of Rapoport's rule to U.S. tree species. Data presented here suggest that Rapoport's rule does indeed apply to most tree taxa within the United States, but may be taxon specific. In addition, data presented here suggest that tree range patterns consistent with Rapoport's rule in the United States are not restricted to high latitudes and are not the result of a “boundedness effect” but may be intimately linked with the glacial history and physical geography of North America. The analyses conducted here are intended to emphasize the utility of such biogeographic rules even if they are not universally applicable and should, in turn, only be considered biogeographic patterns. [ABSTRACT FROM AUTHOR]

1. Studies of North American streams have shown that hydraulic parameters and stream geomorphology can explain unionid mussel abundance at both the reach and catchment scale. However, few studies have examined applicability of hydrogeomorphic variables across broader spatial scales, such as across whole catchments, or have elucidated conditions under which spates can affect mussel populations in streams. 2. We quantified freshwater mussel abundance and species richness and their physical habitat at 24 sites in eight streams in southern Appalachian catchments in 2000 and 2001. In addition, we modelled site-specific hydraulic parameters during summer baseflow and bankfull stages to estimate high- and low-discharge conditions, respectively. 3. Mussel abundance was related to stream geomorphology, whereas richness was related to stream size. Baseflow habitat parameters explained only minor variation in abundance or richness, and both measures were highly correlated with mean current velocity or stream size. Bankfull shear stress composed a relatively low proportion of overall mussel habitat variability, but it accounted for significant variation in abundance and richness. 4. Mussel abundance was highly variable at sites subject to low-shear stress during spates, whereas abundance always was low at sites subject to high-shear stress. These data suggest that habitat conditions during floods, rather than those at summer baseflow, limit the abundance of mussels in Appalachian streams. These data also suggest that mussel abundance and assemblage structure may be sensitive to any changes in channel geomorphology and hydraulic conditions that might result from land use in the catchment. [ABSTRACT FROM AUTHOR]

An active learning project in an introductory graduate course used multidimensional scaling of the name index in Geography in America at the Dawn of the 21st Century, by Gary Gaile and Cort Willmott, to reveal some features of the discipline's recent intellectual structure relevant to the relationship between human and physical geography. Previous analyses, dating to the 1980s, used citation indices or Association of American Geographers specialty-group rosters to conclude that either the regional or the methods and environmental subdisciplines bridge human and physical geography. The name index has advantages over those databases, and its analysis reveals that the minimal connectivity that occurs between human and physical geography has recently operated more through environmental than through either methods or regional subdisciplines. [ABSTRACT FROM AUTHOR]

Historical sources indicate that, in the late 19th century, the portion of the southern California coastline between Palos Verdes Peninsula and San Mateo Point was composed of a series of barrier spits backed by estuaries, beaches backed by cliffs, and occasional rocky headlands. Nearly natural conditions, a reflection of minimal human impact, prevailed during this relatively stormy interval. US Coast [and Geodetic] Survey materials, early scientific work, newspaper articles, and the accounts of travelers provide much of the information utilized to reconstruct the shoreline. Serving as a major roadway, the beach that extended between San Juan Creek and San Mateo Creek was especially well known. The barrier spits were capped by low dunes and were separated by migrating inlets connecting the ocean with the backing estuaries. Rivers discharged into the estuaries at times, decreasing salinities and depositing sediments. Rocky coastlines are believed to have experienced substantial erosion as high levels of bioerosion and vigorous attack by storm waves is inferred, giving rise to notched cliffs, sea caves, and other erosional forms. Forming part of the seaward fringe of the greater Los Angeles region, today this shoreline is completely developed, serving the commercial and recreational needs of millions of residents and visitors. [ABSTRACT FROM AUTHOR]

The article focuses on the study of broad geographic patterns in the size and structure of species assemblages in the U.S. Macroecological patterns are explained through capacity rules and allocation rules. Capacity rules are the extrinsic processes that determine the structure or composition of the assemblage while allocation rules are the intrinsic processes. Allocation rules are broken into 3 sets, the entry rules, exit rules and transformations. Human activities influence entry rules by changing patterns of allopatry and sympatry. It could also influence exit rules by increasing the rate of local, regional and global extinction.

Abstract: Analysis of climatic and topographic evidence from the Cascade Range of Washington State indicates that glacial erosion limits the height and controls the morphology of this range. Glacial erosion linked to long-term spatial gradients in the ELA created a tilted, planar zone of 373 cirques across the central part of the range; peaks and ridges now rise ≤600 m above this zone. Hypsometric analysis of the region shows that the proportion of land area above the cirques drops sharply, and mean slopes >30° indicate that the areas above the cirques may be at or near threshold steepness. The mean plus 1σ relief of individual cirque basins (570 m) corresponds to the ∼600-m envelope above which peaks rarely rise. The summit altitudes are set by a combination of higher rates of glacial and paraglacial erosion above the ELA and enhanced hillslope processes due to the creation of steep topography. On the high-precipitation western flank of the Cascades, the dominance of glacial and hillslope erosion at altitudes at and above the ELA may explain the lack of a correspondence between stream-power erosion models and measured exhumation rates from apatite (U-Th/He) thermochronometry. [Copyright &y& Elsevier]

The article discusses issues related coastal geomorphology in the U.S. It should be noted that there continues to be a clear trend away from the centrality of geomorphology and geography. It even appears that coastal geomorphologists are no longer publishing in major geomorphology journals. There is little evidence to suggest that coastal geomorphology is making significant contributions to the broader theoretical framework of geomorphology. The author offers some commentary on the position of coastal geomorphology within Geomorphology and Physical Geography, based on the progress made over the last three years.

Abstract: Equilibrium line altitude (ELA) estimates for Last Glacial Maximum (LGM) paleoglaciers in Mexico, Guatemala, Costa Rica, Colombia, and Venezuela were determined using the accumulation area balance ratio (AABR), accumulation area ratio (AAR), toe-to-headwall altitude ratio (THAR), and the maximum altitude of lateral moraine (MALM) methods. LGM glacial expansions are chronologically constrained in Mexico, the Mérida Andes of Venezuela, the mountains around Bogotá, Colombia, and the Ruíz-Tolima massif, Colombia. Undated glacial sites are tentatively correlated to dated sites on the basis of similar moraine morphology and weathering characteristics. LGM ELAs are 3400–3950m in central Mexico, 3544m for Guatemala, 3477±13m for Costa Rica, 4104±197m for the Sierra Nevada de Santa Marta, Colombia, 3480m for the Ruíz-Tolima region of Colombia, 3345±130m for the mountains around Bogotá, Colombia, 4151±181m for the Sierra Nevada de Cocuy, Colombia, and 3576±163m for the Mérida Andes of Venezuela. As the modern ELA and/or 0°C isotherm is found at 4900±200m, LGM ELA depression in the circum-Caribbean region was between 500 and 1625m. [Copyright &y& Elsevier]

During the AD 1990s the Waubay Lakes complex in eastern South Dakota experienced historically unprecedented high water levels. Property damage from this flooding led to an examination of the occurrence of past pluvial episodes and their relation to climate. A 1000-year hydroclimate reconstruction was developed from local bur oak (Quercus macrocarpa) tree-ring records and lake-sediment cores. Analysis of lake shoreline and drainage features provides late-Quaternary geomorphic context for this high-resolution record. Tree-ring width and shell geochemistry of the ostracode Candona rawsoni show marked coherence, indicating synchronous responses to moisture balance in vegetation and lake salinity; geomorphic evidence suggests buffering of lake-system expansion during pluvial periods by evaporative dynamics. Pluvial periods display a recurrence frequency of approximately 140–160 years over the past millennium. Prior to AD 1800, both lake highstands and droughts tended towards greater persistence than during the past two centuries. Frequency and timing of hydroclimatic oscillations show strong similarities to records from other sites in the Northern Great Plains (NGP) of North and South Dakota, and incomplete coherence with records of southern Manitoba. [ABSTRACT FROM AUTHOR]

Focuses on the effects of weather and climate impact on human activities in the U.S. Usage of climate data and information on broad range of social, economic and environmental applications; Implications of heat waves on lifestyles and health of affected population.

In this essay, I attempt to chronicle and assess the position of climatology in American geography during the past one hundred years with emphasis on the role of papers published in the Annals. The approach I take is influenced by my interest in the decline of physical geography, including climatology, beginning in the last half of the 1800s ( ) to its resurgence in the 1950s and 1960s, and reviews of the climatology literature that have appeared recently (e.g., ). I discuss climatology in American geography in three loosely defined periods. The first is the formative era in which physical geography, including climatology, was a dominant part of our discipline, and physical geographical conditions such as climate were considered determinants of human affairs. In the middle (regional) era, the physical geographic environment, including climatology, was largely taken to be a static physical milieu or “stage” on which human activity occurred, simply to be described by geographers as part of regional analyses. The modern era, which begins just after the Second World War, is a period of increasing diversity of subject matter and method in climatology within geography and in American geography generally. Today climatology enjoys a “growth industry” status that hardly could be imagined forty years ago. These changes did not occur in isolation but in the context of the scientific, technological, social, economic, and political conditions, and changes in which they were embedded, and the status of climatology as a field of study was an important part of the context. I also comment on the number of climatology papers published in the Annals, including a curious anomaly in the last decade. [ABSTRACT FROM AUTHOR]

In northern Nunavik, orientation of ice-flow features and dispersal patterns of lithologic indicators suggest three major regional ice-flow phases. The oldest ice-flow phase is related to the buildup of an outflow centre, the Ungava centre, over the high plateaux located north of the Povungnituk Hills. During that event, probably of Early Wisconsinan age, ice flows towards the south and southeast carried Cape Smith Belt rock fragments over a maximum distance of 65 km. The second phase is characterized by ice flow mainly towards the north from an outflow ice centre located south of the studied area (Payne centre). The most recent ice-flow phase is related to the presence of the northern extension of the New-Quebec ice divide. From that northwest-trending ice divide extending between Ivujivik and Lake Nantais, ice was flowing outward on the peninsula. The orientation of most of the ice-flow features and dispersal patterns is associated with that last ice flow. North of the Cape Smith Belt, glacial transport was at least 70 km. In Hudson Strait, ice-flow and glacial transport data support the existence of an eastward flowing ice stream. [ABSTRACT FROM AUTHOR]

Tillamook Bay on the northern Oregon coast has experienced significant sediment accumulation and shoaling. Analyses show that part of the increased sedimentation was a result of substantial human impacts in the watersheds of the five rivers that drain into the bay. River discharges were enhanced by approximately 13% during the period 1931–1954, when commercial logging and a series of devastating forest fires occurred, compared with discharges in the years after reforestation. Potential annual sediment yields calculated from daily discharges were enhanced by 29% during 1931–1954, but actual yields would have been substantially greater as a result of increased erosion rates because of deforestation. Sand transported by the rivers consists primarily of rock fragments, in contrast to the quartz and feldspar sand carried into the bay from the ocean beach. Surface sediments collected throughout the bay consist, on average, of about 40% sand from the rivers and 60% from the ocean beach. Cores show increasing percentages of beach sand beneath the surface, with evidence for major episodic inputs rather than the higher percentages of river derived rock fragments that human impacts would have produced. Subduction earthquakes have struck the Oregon coast repeatedly during the past several thousand years; the most recent was in January 1700. The down core increase in beach derived sand in Tillamook Bay is from sand transport by the tsunami that accompanied the 1700 earthquake and the deepening of the bay from land subsidence at the time of the earthquake, which permitted more frequent and extensive spit overwash events during storms. [ABSTRACT FROM AUTHOR]

Correlation of continental shelf-slope stratigraphy in Santa Monica Bay (southern California) with Ocean Drilling Program records for nearby slope-basin sites has illuminated the timing and scale of terrigenous sediment dispersal on margin since the Last Glacial Maximum (LGM). Marine flooding surfaces preserved in a transgressive sequence on the Santa Monica Shelf provide a key link between base-level elevation and sediment transport across shelf. Sediment-accumulation rates at slope-basin sites were maximal ca. 15-10 ka, well after the LGM, decreased during the 12-9 ka transition from fluvial-estuarine to fully marine conditions on the shelf, and decelerated throughout the Holocene to 30%-75% of their values at the LGM. The deceleration is interpreted to manifest a landward shift in the margin depocenter with the onset of transgressive sedimentation beginning when sea level surmounted the shelf edge ca. 13 ka, as predicted by sequence-stratigraphic models. However, the records make clear that factors other than base level modulated slope-basin accumulation rates during the deglaciation. [ABSTRACT FROM AUTHOR]

The sediments of Santa Barbara Basin, a valuable source of information about the history of the California Current, show cyclic deposition in three properties here investigated: varve thickness, total organic carbon (TOC) accumulation, and fish-scale abundance. We analyzed the record since A.D. 1350 for varves, A.D. 1120 for TOC, and A.D. 1200 for fish scales. Prominent periods are 169 yr, 93 yr, 51.4 yr, 17.7 yr (varve thickness), 124 yr, 56 yr, 37.4 yr (TOC flux), and 103 yr, 128 yr (fish-scale abundance). A surprising number of the varve and TOC cycles can be interpreted as deriving from the common tidal cycles, i.e., the 4.425 yr perigee period (describing the changing distance between Earth and Moon) and the 18.6 yr lunar nodal period (which pertains to the lineup of Earth, Moon, and Sun). We suggest that the record of the basin is partly a result of pulsed sedimentation aligned with tides. These findings support the hypothesis that a considerable portion of sediment destined for deposition in the center of the basin goes through a phase of shallow storage on the shelf where it can be remobilized through storms and tides. Mechanisms calling on tidally pulsed productivity or tidally influenced climate change are not excluded, but are considered less attractive than remobilization. Fish-scale cycles may reflect the influence of solar forcing. [ABSTRACT FROM AUTHOR]

It is well established that elevations determined by global position systems are above reference ellipsoid heights and should be corrected for geoid undulation to determine the orthometric height or mean sea-level elevation. The paper describes research performed at Iowa State University in cooperation with Iowa Department of Transportation to determine the local geoid, N1, with &plusm,n;2 cm accuracy for a countywide area, study its variation with time, and develop a method to predict the future local geoid with ±2 cm accuracy. This paper describes the data collection method, provides the results of three observations at six-month intervals for studying the variation Of N1with time; explains a method developed for predicting N1 and determining agreement with a fourth observation; and describes a procedure for establishing elevation control by global positioning systems for leveling and for establishing control in a real-time kinematic global positioning systems project. [ABSTRACT FROM AUTHOR]

Scarp morphology evolution has commonly been used to estimate the timing of fault-scarp rupture events. However, rates of scarp degradation depend strongly on the geomorphic diffusivity, a parameter that is difficult to constrain independently. This difficulty may lead to large uncertainties in the estimated ages of rupture events. In this study, we have coupled the accumulation of the cosmogenic nuclide 36Cl to a model for scarp morphology in order to constrain the value of the geomorphic diffusivity and thus determine a more accurate rupture chronology than a rupture history based solely on scarp morphology. We measured depth profiles of 36Cl accumulated in situ within alluvial sediments beneath the surface of the Socorro Canyon fault scarp in central New Mexico. The material analyzed consisted of ∼150 individual gravel clasts from each depth interval, amalgamated into a single sample. The alluvium was sampled in three vertical profiles ∼4 m deep. The first profile was ∼1.5 m downslope of the fault plane on the hanging wall, the second ∼1.5 m upslope of the fault plane on the footwall, and the third ∼27 m upslope of the fault plane on the footwall. The third profile, which served as a control, and which soil geomorphic evidence indicated was beneath a stable surface, showed a simple exponential 36Cl profile from which a depositional age of 122±18 ka was calculated. The second profile (on the footwall) showed a 36Cl deficit relative to the control profile, indicating net erosion. The first profile (on the hanging wall) showed a 36Cl excess relative to the control profile, indicating net deposition. Stratigraphic evidence in the hanging wall indicated two rupture events prior to the Late Holocene. We modeled the accumulation of 36Cl in the vicinity of the scarp, simulating erosional redistribution using a diffusion equation for scarp morphology. The model accounted for redistribution of 36Cl along with the sediment and the effects of the changing fault-scarp morphology on the 36Cl production. By matching both the observed hanging-wall and footwall 36Cl profiles to profiles calculated by the model, as well as the observed topographic profile, we obtained ages of 92+16−13 and 28+18−23 ka for the two ruptures. The results of our study indicate that cosmogenic nuclides can be useful in constraining rupture chronologies of fault scarps in alluvium. [Copyright &y& Elsevier]

Examines how water governance institutions affect the implementation of conjunctive management in Western states namely, Arizona, California and Colorado. Purpose and benefits of conjunctive management; Factors that account for the increase in the calls for the implementation of conjunctive management; Physical and socioeconomic characteristics of the states; Differences in the extent and types of conjunctive management activities in the states.

Describes the cultural, social and geographical landscape in Minnesota. Account on the population distribution, immigration and settlement system; Displacement of native Indian population; Discussion on national growth and regional economic transition; Development of racial and economic segregation among school children.

Attempts to examine institutional and material origins of a geographic culture of letters, and the ways in which individual citizens came to visualize regional communities within a figurative nation and themselves as national characters. Idea of a nation as a cultural artifact; Invention of nationalism by printed geographical materials; Demand for geographic tests.

Two Woodfordian glaciated regions in Wisconsin were analyzed to determine the impact of variable loess thickness and contrasting till texture on soil pattern and landscape properties. Each region consisted of a ground moraine/end moraine/outwash plain landform sequence. Data were compiled from soil and topographic maps. In addition to using standard methods of soilscape analysis. I used a natural soil drainage index, calculated from taxonomic data, to determine regional variability and pattern of soil wetness. Results indicate that soilscape variation within each region was large. There were no statistically significant differences, therefore, that could be attributed to known soil- forming processes or to parent material variability. Stratifying the data by geomorphic subregion rather than by region reduced the within-unit soil variability and resulted in numerous significant soilscape differences between subregions. The implication is that soilscape variability is large at the regional scale but converges rapidly with decreasing size of study area. [ABSTRACT FROM AUTHOR]

Measurements of discharge, reach morphology, and cross-section morphology in supraglacial streams on the Juneau Icefield reveal controlling variables that have analogous counterparts in alluvial streams. Downward sky radiation imparts a strong diurnal pattern to supraglacial runoff generated by saturated slush flows, precipitation and melting, channel erosion, and spillover from water-filled moulins, crevasses, and supraglacial lakes. Supraglacial streams are generated when runoff is concentrated on glacier slopes and rates of incision exceed rates of glacier surface ablation. Streams leave the surface via moulins and crevasses where the water becomes part of the englacial and subglacial drainage systems. Meander systems develop and migrate downstream, driven by thermal erosion with heat supplied by climatic and hydrologic sources. Sinuosity attains a maximum value, in the absence of other roughness factors, when high stream power is imposed from an adjacent upstream reach. Form-process relationships for supraglacial meanders are similar to those for alluvial streams in spite of the contrast in time and scale of development. At-a-station hydraulic geometry for supraglacial streams serves to identify channel adjustments to changing discharge not unlike those for narrow-deep, straight alluvial streams. Daily formation of longitudinal grooves in channel walls leaves a record of daily flow and yields critical information regarding channel enlargement ratios. Fluvial adjustment toward equilibrium conditions involves all elements of channel roughness and cannot be analyzed using any single indicator such as channel pattern, cross-sectional shape, or materials involved. [ABSTRACT FROM AUTHOR]