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- Creators: Arizona State University
Description
Extreme hot-weather events have become life-threatening natural phenomena in many cities around the world, and the health impacts of excessive heat are expected to increase with climate change (Huang et al. 2011; Knowlton et al. 2007; Meehl and Tebaldi 2004; Patz 2005). Heat waves will likely have the worst health impacts in urban areas, where large numbers of vulnerable people reside and where local-scale urban heat island effects (UHI) retard and reduce nighttime cooling. This dissertation presents three empirical case studies that were conducted to advance our understanding of human vulnerability to heat in coupled human-natural systems. Using vulnerability theory as a framework, I analyzed how various social and environmental components of a system interact to exacerbate or mitigate heat impacts on human health, with the goal of contributing to the conceptualization of human vulnerability to heat. The studies: 1) compared the relationship between temperature and health outcomes in Chicago and Phoenix; 2) compared a map derived from a theoretical generic index of vulnerability to heat with a map derived from actual heat-related hospitalizations in Phoenix; and 3) used geospatial information on health data at two areal units to identify the hot spots for two heat health outcomes in Phoenix. The results show a 10-degree Celsius difference in the threshold temperatures at which heat-stress calls in Phoenix and Chicago are likely to increase drastically, and that Chicago is likely to be more sensitive to climate change than Phoenix. I also found that heat-vulnerability indices are sensitive to scale, measurement, and context, and that cities will need to incorporate place-based factors to increase the usefulness of vulnerability indices and mapping to decision making. Finally, I found that identification of geographical hot-spot of heat-related illness depends on the type of data used, scale of measurement, and normalization procedures. I recommend using multiple datasets and different approaches to spatial analysis to overcome this limitation and help decision makers develop effective intervention strategies.
ContributorsChuang, Wen-Ching (Author) / Gober, Patricia (Thesis advisor) / Boone, Christopher (Committee member) / Guhathakurta, Subhrajit (Committee member) / Ruddell, Darren (Committee member) / Arizona State University (Publisher)
Created2013
Description
In recent years, an increase of environmental temperature in urban areas has raised many concerns. These areas are subjected to higher temperature compared to the rural surrounding areas. Modification of land surface and the use of materials such as concrete and/or asphalt are the main factors influencing the surface energy balance and therefore the environmental temperature in the urban areas. Engineered materials have relatively higher solar energy absorption and tend to trap a relatively higher incoming solar radiation. They also possess a higher heat storage capacity that allows them to retain heat during the day and then slowly release it back into the atmosphere as the sun goes down. This phenomenon is known as the Urban Heat Island (UHI) effect and causes an increase in the urban air temperature. Many researchers believe that albedo is the key pavement affecting the urban heat island. However, this research has shown that the problem is more complex and that solar reflectivity may not be the only important factor to evaluate the ability of a pavement to mitigate UHI. The main objective of this study was to analyze and research the influence of pavement materials on the near surface air temperature. In order to accomplish this effort, test sections consisting of Hot Mix Asphalt (HMA), Porous Hot Mix asphalt (PHMA), Portland Cement Concrete (PCC), Pervious Portland Cement Concrete (PPCC), artificial turf, and landscape gravels were constructed in the Phoenix, Arizona area. Air temperature, albedo, wind speed, solar radiation, and wind direction were recorded, analyzed and compared above each pavement material type. The results showed that there was no significant difference in the air temperature at 3-feet and above, regardless of the type of the pavement. Near surface pavement temperatures were also measured and modeled. The results indicated that for the UHI analysis, it is important to consider the interaction between pavement structure, material properties, and environmental factors. Overall, this study demonstrated the complexity of evaluating pavement structures for UHI mitigation; it provided great insight on the effects of material types and properties on surface temperatures and near surface air temperature.
ContributorsPourshams-Manzouri, Tina (Author) / Kaloush, Kamil (Thesis advisor) / Wang, Zhihua (Thesis advisor) / Zapata, Claudia E. (Committee member) / Mamlouk, Michael (Committee member) / Arizona State University (Publisher)
Created2013
Description
The Urban Heat Island (UHI) has been known to have been around from as long as people have been urbanizing. The growth and conglomeration of cities in the past century has caused an increase in the intensity and impact of Urban Heat Island, causing significant changes to the micro-climate and causing imbalances in the temperature patterns of cities. The urban heat island (UHI) is a well established phenomenon and it has been attributed to the reduced heating loads and increased cooling loads, impacting the total energy consumption of affected buildings in all climatic regions. This thesis endeavors to understand the impact of the urban heat island on the typical buildings in the Phoenix Metropolitan region through an annual energy simulation process spanning through the years 1950 to 2005. Phoenix, as a representative city for the hot-arid cooling-dominated region, would be an interesting example to see how the reduction in heating energy consumption offsets the increased demand for cooling energy in the building. The commercial reference building models from the Department of Energy have been used to simulate commercial building stock, while for the residential stock a representative residential model prescribing to IECC 2006 standards will be used. The multiyear simulation process will bring forth the energy consumptions of various building typologies, thus highlighting differing impacts on the various building typologies. A vigorous analysis is performed to see the impact on the cooling loads annually, specifically during summer and summer nights, when the impact of the 'atmospheric canopy layer' - urban heat island (UHI) causes an increase in the summer night time minimum and night time average temperatures. This study also shows the disparity in results of annual simulations run utilizing a typical meteorological year (TMY) weather file, to that of the current recorded weather data. The under prediction due to the use of TMY would translate to higher or lower predicted energy savings in the future years, for changes made to the efficiencies of the cooling or heating systems and thermal performance of the built-forms. The change in energy usage patterns caused by higher cooling energy and lesser heating energy consumptions could influence future policies and energy conservation standards. This study could also be utilized to understand the impacts of the equipment sizing protocols currently adopted, equipment use and longevity and fuel swapping as heating cooling ratios change.
ContributorsDoddaballapur, Sandeep (Author) / Bryan, Harvey (Thesis advisor) / Reddy, Agami T (Committee member) / Addison, Marlin (Committee member) / Arizona State University (Publisher)
Created2011
Description
Metropolitan Phoenix, Arizona, is one of the most rapidly urbanizing areas in the U.S., which has resulted in an urban heat island (UHI) of substantial size and intensity. Several detrimental biophysical and social impacts arising from the large UHI has posed, and continues to pose, a challenge to stakeholders actively engaging in discussion and policy formulation for a sustainable desert city. There is a need to mitigate some of its detrimental effects through sustainable methods, such as through the application of low-water, desert-adapted low-water use trees within residential yards (i.e. urban xeriscaping). This has the potential to sustainably reduce urban temperatures and outdoor thermal discomfort in Phoenix, but evaluating its effectiveness has not been widely researched in this city or elsewhere. Hence, this dissertation first evaluated peer-reviewed literature on UHI research within metropolitan Phoenix and discerned several major themes and factors that drove existing research trajectories. Subsequently, the nocturnal cooling influence of an urban green-space was examined through direct observations and simulations from a microscale climate model (ENVI-Met 3.1) with an improved vegetation parameterization scheme. A distinct park cool island (PCI) of 0.7-3.6 °C was documented from traverse and model data with larger magnitudes closer to the surface. A key factor in the spatial expansion of PCI was advection of cooler air towards adjacent urban surfaces, especially at 0-1 m heights. Modeled results also possessed varying but reasonable accuracy in simulating temperature data, although some systematic errors remained. Finally, ENVI-Met generated xeriscaping scenarios in two residential areas with different surface vegetation cover (mesic vs. xeric), and examined resulting impacts on near-surface temperatures and outdoor thermal comfort. Desert-adapted low-water use shade trees may have strong UHI mitigation potential in xeric residential areas, with greater cooling occurring at (i.) microscales (~2.5 °C) vs. local-scales (~1.1 °C), and during (ii.) nocturnal (0500 h) vs. daytime periods (1700 h) under high xeriscaping scenarios. Conversely, net warming from increased xeriscaping occurred over mesic residential neighborhoods over all spatial scales and temporal periods. These varying results therefore must be considered by stakeholders when considering residential xeriscaping as a UHI mitigation method.
ContributorsChow, Winston T. L (Author) / Brazel, Anthony J. (Thesis advisor) / Grossman-Clarke, Susanne (Committee member) / Martin, Chris A (Committee member) / Arizona State University (Publisher)
Created2011
Description
This dissertation explores vulnerability to extreme heat hazards in the Maricopa County, Arizona metropolitan region. By engaging an interdisciplinary approach, I uncover the epidemiological, historical-geographical, and mitigation dimensions of human vulnerability to extreme heat in a rapidly urbanizing region characterized by an intense urban heat island and summertime heat waves. I first frame the overall research within global climate change and hazards vulnerability research literature, and then present three case studies. I conclude with a synthesis of the findings and lessons learned from my interdisciplinary approach using an urban political ecology framework. In the first case study I construct and map a predictive index of sensitivity to heat health risks for neighborhoods, compare predicted neighborhood sensitivity to heat-related hospitalization rates, and estimate relative risk of hospitalizations for neighborhoods. In the second case study, I unpack the history and geography of land use/land cover change, urban development and marginalization of minorities that created the metropolitan region's urban heat island and consequently, the present conditions of extreme heat exposure and vulnerability in the urban core. The third study uses computational microclimate modeling to evaluate the potential of a vegetation-based intervention for mitigating extreme heat in an urban core neighborhood. Several findings relevant to extreme heat vulnerability emerge from the case studies. First, two main socio-demographic groups are found to be at higher risk for heat illness: low-income minorities in sparsely-vegetated neighborhoods in the urban core, and the elderly and socially-isolated in the expansive suburban fringe of Maricopa County. The second case study reveals that current conditions of heat exposure in the region's urban heat island are the legacy of historical marginalization of minorities and large-scale land-use/land cover transformations of natural desert land covers into heat-retaining urban surfaces of the built environment. Third, summertime air temperature reductions in the range 0.9-1.9 °C and of up to 8.4 °C in surface temperatures in the urban core can be achieved through desert-adapted canopied vegetation, suggesting that, at the microscale, the urban heat island can be mitigated by creating vegetated park cool islands. A synthesis of the three case studies using the urban political ecology framework argues that climate changed-induced heat hazards in cities must be problematized within the socio-ecological transformations that produce and reproduce urban landscapes of risk. The interdisciplinary approach to heat hazards in this dissertation advances understanding of the social and ecological drivers of extreme heat by drawing on multiple theories and methods from sociology, urban and Marxist geography, microclimatology, spatial epidemiology, environmental history, political economy and urban political ecology.
ContributorsDeclet-Barreto, Juan (Author) / Harlan, Sharon L (Thesis advisor) / Bolin, Bob (Thesis advisor) / Hirt, Paul (Committee member) / Boone, Christopher (Committee member) / Arizona State University (Publisher)
Created2013
Description
As the planet is rapidly urbanizing, understanding the ecological effects of urbanization is a grand challenge for modern biology. For example, increased city temperatures known as the urban heat island effect, disproportionately impact nocturnal taxa and this consideration is widely overlooked. Slight shifts in the thermal microclimate have a cascade of ramifications that directly impact species density and distribution. Animal behavior is a trait that may explain why some species thrive after urbanization when others go locally extinct. In this study I followed 22 adult females of the western black widow, Latrodectus hesperus, from both urban and undisturbed Sonoran Desert habitats. First, I began looking for differences between urban and desert spiders under field conditions: boldness, voracity, web size and body condition. Both urban and desert spiders were then brought to the laboratory to see how their behavior changed. I found no behavioral differences between urban and desert spiders in the field or the laboratory. I did find that spider behavior differed between the field and the laboratory. Specifically, boldness in the laboratory was significantly lower compared to the field. Voracity was more repeatable in the laboratory versus the field, and boldness was strongly positively correlated with voracity in the laboratory, but not in the field. These behavioral shifts from the field to the laboratory favor the conclusion that black widow behavior is highly plastic and context dependent. Lastly, I monitored web temperature of black widow microhabitat continuously for an entire year using iButton data loggers. I found microhabitat temperatures differences between urban and desert sites were greatest at night and absent during the daytime. I uncovered a seasonal effect with the highest magnitude temperature difference occurring during the springtime. Additionally, behavior was significantly correlated with field temperatures; the boldest spiders come from the warmest webs. However, I found little evidence that temperature predicts spider body condition or voracity, and body condition does not predict its behavioral expression. My results highlight the importance of studying animal behavior to increase understanding of the factors that shape distribution and density in a lethal pest species.
ContributorsClark, Ryan Carter (Author) / Johnson, James C (Thesis advisor) / Bang, Christofer (Thesis advisor) / Sullivan, Brian (Committee member) / Arizona State University (Publisher)
Created2021
Description
The Philippine Sea refers to the East and West Philippine Sea that are within the sovereign territory of the 7,641 islands of the Philippine archipelago. Historically, Spain, the United States, and Japan have colonized the islands, and the United States and China continue to maintain imperial interests in the area. Filipino/a/x diasporic activists in the U.S. and allies have participated in the anti-imperial struggle in support of demilitarization of the Pacific and of neo-colonized states across the globe. Responding to the problematics of anti-imperialism and solidarity, this dissertation advances the concept of agos or moving relations to attune to the sea as an analytic in theorizing activism, communication, and performance. This project was written on the unceded ancestral homelands of the Onk Akimel O’odham and Xalychidom Piipash, was inspired by the works of Black and Indigenous communities and scholars, and was influenced by Kale Fajardo’s notion of crosscurrents and Loma Cuevas-Hewitt’s concept of archipelagic poetics. Across critical organizational communication, critical intercultural communication, and performance studies, agos theorizes the relationalities of movements and the movements of relationalities. Utilizing critical qualitative, rhetorical, and performance methods, this project develops three instantiations of agos. In “Whirlpool Organizing,” the processes of anti-imperial organizers’ relationship and coalition building are examined to demonstrate the liquidities that animate dialectics and differences. In “Anchored Relationality,” U.S. diasporic Filipino/a/x’ varied and complex reconnections with Philippine waters are explored to illustrate the fluidities of positions and relations. In “Archipelagic Performance,” the staged production of “What sounds do turtles make?” is analyzed to showcase the flows of a decolonial and relational mode of performance.
ContributorsLabador, Ma Angela San Luis (Author) / LeMaster, Loretta (Thesis advisor) / Kim, Heewon (Thesis advisor) / Leong, Karen (Committee member) / Hastings, Rachel (Committee member) / Arizona State University (Publisher)
Created2023
Description
Black Americans and Black folks across the globe continue to proclaim variousunfreedoms we experience specifically due to our Blackness. As we struggle against and
survive through the unfair structures, ways of being, and conditions that are killing us, we
have been creating new survival strategies for living. One of our primary arguments is
that state entities and the anti-Black carcerality embedded in them (e.g., policing, prisons,
hospitals, welfare systems, military, the foster care system educational institutions etc.)
are the primary arbitrators weaponizing violence, injustice, and unfreedom in our lives.
Since the Black Lives Matter uprising in 2013 due to the murder of Trayvon Martin,
leading up to the largest global uprising in 2020 due to the murder of George Floyd, and
the ongoing activism around anti-Black police violence, we who are organizers and
activists have found ourselves seeking out alternative ways to be principled in our
struggles for abolition, transformative justice, and Black liberation. A part of being in
principled struggle is building a praxis (when theory meets practice) of how to conduct
oneself in community with others, and with the state in a way that is aligned with stated
values and beliefs. Much of the organizing work geared towards eradicating anti-Black
violence pulls from the theoretical and practiced interventions of the Black radical
tradition, Black feminist thought, and abolitionism(s) to inform their praxis. This
dissertation will seek out a Black radical queer feminist praxis by conducting an auto-
ethnography using critical art-based Black feminist-womanist storytelling to measure
data collected from my lived experiences as an organizer and activist to uplift the
liberation strategies of an era.
ContributorsAraya, Miriam (Author) / Anderson, Lisa (Thesis advisor) / Duarte, Marisa (Committee member) / Alhassan, Shamara (Committee member) / Arizona State University (Publisher)
Created2024
Description
This study investigates the energy saving potential of high albedo roof coatings which are designed to reflect a large proportion of solar radiation compared to traditional roofing materials. Using EnergyPlus simulations, the efficacy of silicone, acrylic, and aluminum roof coatings is assessed across two prototype commercial buildings—a standalone retail (2,294 m2 or 24,692 ft2) and a strip-mall (2,090 m2 or 22,500 ft2)—located in four cities: Phoenix, Houston, Los Angeles, and Miami. The performance of reflective coatings was compared with respect to a black roof having a solar reflectance of 5% and a thermal emittance of 90%. A sensitivity analysis was done to assess the impact of solar reflectance and thermal emittance on the ability of roof coatings to reduce surface temperatures, a key factor behind energy savings. This factor plays a crucial role in all three heat transfer mechanisms: conduction, convection, and radiation. The rooftop surface temperature exhibits considerable variation depending on the solar reflectance and thermal emittance attributes of the roof. A contour plot between these properties reveals that high values of both result in reduced cooling needs and a heating penalty which is insignificant when compared with cooling savings for cooling-dominant climates like Phoenix where the cooling demand significantly outweighs the heating demand, yielding significant energy savings. Furthermore, the study also investigates the effects of reflective coatings on buildings that have photovoltaic solar panels installed on them. This includes exploring their impact on building HVAC loads, as well as the performance improvement due to the reduced temperatures beneath them.
ContributorsSharma, Ajay Kumar (Author) / Phelan, Patrick (Thesis advisor) / Neithalath, Narayanan (Committee member) / Milcarek, Ryan (Committee member) / Arizona State University (Publisher)
Created2024
Description
In this dissertation, I grapple with the compelling question: Why have women’s mobilizations in Latin America not only increased but also become increasingly confrontational towards the state and other institutions, even amid a longstanding rise in progressive gender-based legislation and policies? This inquiry unfolds against a backdrop of diverse theoretical perspectives on women’s engagement in contentious politics. This introspection has led to the formulation of a theoretical mechanism, which posits that neither the proliferation of gender-progressive policies, windows of opportunity, nor grievances are sole precipitating factors. Instead, the emergence of the ‘legal facade’ – spawned by this structural political opportunity - incites further contentious actions. These are intertwined with the development of a collective conscience, anchored in a sense of shared destiny, amplified by both fear and hope. To elucidate the activists’ experiences, I employ a methodological blend of case-process tracing and narrative analysis. This ‘legal facade’ embodies the systematic failures of the state and informal institutions to effectively address women’s violence and inequalities, resulting in the superficial enactment of numerous policies and laws that have deep flaws in their design, execution, and evaluation.
ContributorsPaez, Camila (Author) / Hinojosa, Magfa (Thesis advisor) / Kittilson, Miki (Committee member) / Kirkpatrick, Jennet (Committee member) / Kaire, Jose (Committee member) / Arizona State University (Publisher)
Created2024