Andrew J. Krmenec

Vulnerability due to Nocturnal Tornadoes

This study investigates the human vulnerability caused by tornadoes that occurred between sunset and sunrise from 1880 to 2007. Nocturnal tornadoes are theorized to enhance vulnerability because they are difficult to spot and occur when the public tends to be asleep and in weak building structures. Results illustrate that the nocturnal tornado death rate over the past century has not shared the same pace of decline as those events transpiring during the daytime. From 1950 to 2005, a mere 27.3% of tornadoes were nocturnal, yet 39.3% of tornado fatalities and 42.1% of killer tornado events occurred at night. Tornadoes during the overnight period (local midnight to sunrise) are 2.5 times as likely to kill as those occurring during the daytime hours. It is argued that a core reason why the national tornado fatality toll has not continued to decrease in the past few decades is due to the vulnerability to these nocturnal events. This vulnerability is magnified when other factors such as escalating mobile (or “manufactured”) home stock and an increasing and spreading population are realized. Unlike other structure types that show no robust demarcation between nocturnal and daytime fatalities, nearly 61% of fatalities in mobile homes take place at night revealing this housing stock’s distinct nocturnal tornado vulnerability. Further, spatial analysis illustrates that the American South’s high nocturnal tornado risk is an important factor leading to the region’s high fatality rate. The investigation emphasizes a potential break in the tornado warning dissemination system utilized currently in the United States.

Spatiotemporal Changes in Tornado Hazard Exposure: The Case of the Expanding Bull’s-Eye Effect in Chicago, Illinois

AbstractExposure has amplified rapidly over the past half century and is one of the primary drivers of increases in disaster frequency and consequences. Previous research on exposure change detection has proven limited since the geographic units of aggregation for decennial censuses, the sole measure of accurate historical population and housing counts, vary from one census to the next. To address this shortcoming, this research produces a set of gridded population and housing data for the Chicago, Illinois, region to evaluate the concept of the “expanding bull’s-eye effect.” This effect argues that “targets”—people and their built environments—of geophysical hazards are enlarging as populations grow and spread. A collection of observationally derived synthetic violent tornadoes are transposed across fine-geographic-scale population and housing unit grids at different time stamps to appraise the concept. Results reveal that intensifying and expanding development is placing more people and their possession...

Authorship, Collaboration, and Gender: Fifteen Years of Publication Productivity in Selected Geography Journals

In academia, publication productivity, defined as the number of peer-reviewed articles published and the frequency of citations, is a primary factor in the assessment of tenure and promotion. One of the most cited gender differences in academia is the “productivity puzzle,” which suggests that women publish less than men, thereby affecting every aspect of a womans academic career. Peer-reviewed articles published in the Annals of the Association of American Geographers (Annals) and The Professional Geographer (PG) between 1995 and 2006, and in four subdisciplinary journals between 2005 and 2009, as well as citation reports, were used to explore whether gender differences are present in publication productivity. Gender differences were evident in the proportion of women authors, the frequency of collaboration, and the number of citations across a broad range of prestigious geographic journals. For all journals studied, women were underrepresented, especially in the authorship positions that equate to notions of respect and merit. Although the number of collaborative articles increased during the study period, single-authored papers are the dominant mode of publication for both men and women for most geographic journals. The authorship patterns for frequently cited articles generally mirror those for all articles. Because the frequency of collaborative publication was high for women, the dual trends of a general increase in publication collaboration and increasing participation of women in academic geography bodes well for increased female productivity as it relates to publishing. Nevertheless, it is important to note that, currently, males as lead or single authors represent the predominant voice of geography within the journals examined in this study.

The Spatial Extent of Producer Service Markets: Hierarchical Models of Interaction Revisited

The traditional view of interaction in spatial markets has been challenged by recent studies of producer service trade in the space economy. These studies find that although city-size and distance influence the direction and spatial extent of interaction, patterns of trade oftentimes counter expectations as trade flows up the urban hierarchy and across large distances. This paper seeks to determine whether the ownership structure of establishments contributes to deviations from the traditional model of hierarchical interaction. Using trade data obtained from surveys of 547 producer service establishments, patterns of trade originating from a five-tier urban hierarchy are examined empirically and evaluated using spatial survivor functions and logit models. The results indicate that the ownership structure of establishments contributes significantly to deviations from expected patterns of interaction. Independently owned establishments have smaller spatial markets and interact more often with smaller sized cities. Nonindependently owned establishments, in contrast, trade down and up the urban hierarchy in a manner much less sensitive to distance.

A sensitivity assessment of uncertainty in infrastructure expansion

Under and overdesign is a major consideration in public infrastructure expansion. Traditional engineering economies of scale leading to overdesign errors must be counterbalanced by greater attention to high cost financing. Uncertainty in demand forecasting and in financial markets make decision tools which incorporate measures of information imperfection increasingly important. Further issues of overall social welfare make the question of short term and intergenerational equity major concerns. A rational expectations stochastic-analog of the conventional, present value, infrastructure expansion model has optimal overdesign properties. The problem is restated as a two-person, planner vs. future, social welfare game in a simple capital loss model. Sensitivity analysis shows the game-theoretic model which favors expansion underdesign is relatively less sensitive to greater demand forecast uncertainty than the rational expectations model.

Planning for capacity expansion: Stochastic process and game-theoretic approaches

Abstract Under- and over-capacity design is a major consideration in public infrastructure systems. Traditional engineering economies of scale leading to overdesign errors must be counterbalanced by greater attention to high cost financing. Increased uncertainty in demand forecasting and financial markets make decision tools which incorporate measures of information imperfection more appropriate. These tools, however, do not lead to consistent identification of optimal design levels.

Large City Interaction in the US Urban System

Mounting interest in the global system of cities has led many scholars to portray large, world-class cities as control points in the global economy. From this position, they govern global banking, finance and international corporate relations with the assistance of advanced business services and telecommunications. While large cities have taken on many global functions, recent research has cast them only as outposts in the global economy and pays little attention to their role in regional and national economies. This paper explores the role of five large US cities in regional and national economies. Using primary trade data for five high-order business services, we identify the extent to which these large cities trade with other large cities of the US urban system, smaller-sized cities, and test statistically the effect that firm attributes and physical characteristics of the city system have on shaping the areal extent of large city interaction (trade). The results indicate that: trade is consistently biased towards other large cities; the size of origin cities is associated with the size of destination cities; and, distance more so than destination city size plays the dominant role in shaping large city patterns of trade.

City Systems and Industrial Market Structure

Industrial geographers are broadening both the scope and scale of analyses in their quest for deeper understanding of industrial formation and evolution. This has led them to link industrial processes at various spatial scales and to revisit well-defined organizational structures, especially city systems. Taking stock of renewed interest, this paper investigates the relationship between urban regional systems and industrial market structure. The paper demonstrates that the U.S. is composed of urban regional systems that vary in density of urban settlement, and argues that dynamic externalities and barriers to market entry and exit play out within these distinct systems to develop regionalized industry market structures that range from competitive to oligopolistic. An empirical analysis identifies these market structures through use of a Hildreth-Houck variable-coefficients model. Elasticity-of-scale estimates are derived for thirteen consumer and producer services industries at the MSA scale, using 1982 and 1992County Business Patterns data. The results reveal a systematic geography of industry structure generally supportive of the hypotheses linking density of urban settlement to industry market structure. Producer services industries in the western U.S. tend toward oligopolistic market structures, while those in the more densely settled midwest and east are more competitive.

Observed and Projected Changes in United States Tornado Exposure

AbstractThis study examines how tornado risk and societal exposure interact to create tornado disaster potential in the United States. Finescale historical and projected demographic data are used in a set of region-specific Monte Carlo tornado simulations to reveal how societal development has shaped, and will continue to shape, tornado disaster frequency and consequences. Results illustrate that although the U.S. Midwest contains the greatest built-environment exposure and the central plains experience the most significant tornadoes, the midsouth contains the greatest tornado disaster potential. This finding is attributed to the relatively elevated tornado risk and accelerated growth in developed land area that characterizes the midsouth region. Disaster potential is projected to amplify in the United States due to increasing built-environment development and its spatial footprint in at-risk regions. In the four regions examined, both average annual tornado impacts and associated impact variability are p...

Projected 21st century changes in tornado exposure, risk, and disaster potential

While risk and associated hazard characteristics are important components of disaster formation, the consequences of hazards are often driven by underlying human and built-environment vulnerabilities. Yet, there has been little research conducted on how the evolving contributors of risk and vulnerability commingle to produce disaster potential. In this study, we assess the interaction of risk and vulnerability by investigating a single hazard, the tornado. How future changes in risk and vulnerability influence tornado disaster probability is estimated by integrating, for the first time, projected residential built environment data and modeled future severe weather environments. Results suggest that, although the projected twenty-first century escalation in tornado risk will play a role in increasing disaster consequences and frequency, growth in the human-built environment is projected to outweigh the effects of increased risk on future tornado disaster potential. While changes in societal exposure are projected to overshadow potential climate change-driven alterations in tornado risk, the combination of both an increase in risk and exposure may lead to a threefold increase in median annual tornado impact magnitude and disaster potential from 2010 to 2100.