Geography & Atmospheric Science Dissertations and Theses

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  • Publication
    The Geographies of Non-Lethal Weapons: Transformative Technologies and Political Violence
    (University of Kansas, 2019-12-31) Henkin, Samuel
    Non-lethal weapons, like police batons, rubber bullets and tear gas, are increasingly deployed in interventions against a rising number of bodies in contested spaces. They are formed through notions of (in)security and an ethos of the use of force that makes such interventions appear to be ethical and humane. Yet, what is considered ethical or humane about weapons that are used with possible violent and injurious effects is bound to security discourses and practices in an interlocking globalized police-military-network. Transformations in security techniques and technologies engenders a subtle, yet vastly nefarious, “mission creep” where technologies of war are depoliticized as a sensationalization of (in)security drives a robust use of force continuum weaponizing the politics of non-lethality. Shifting articulations and practices of non-lethality in security underpins the increasing militarization and colonization of everyday life by security logics and norms broadening the social utility of disciplinary power. Geographic literature on the logics of security is vigorous, but less attention has been paid to the politics of non-lethality and its operation within contested spaces, contentious politics, and exercises of state disciplinary power. Acknowledgement and better understanding that non-lethality operates at different socio-spatial scales from orbital space right down to the individual body is crucial. Investigating non-lethal state interventionary power recognizes the reinvention of citizens as subjects, as potential sites of political violence and domination in contested spaces. Non-lethal weapons have transformative effects on spaces of governance within the growing international security environment as well as on bodies and the use of force. This project confronts wider programs of state security regarding the use of force, programs that connect violence to order, coercion to lethality and military power to civilian spaces.
  • Publication
    Tracking hydrologic response of tile outlet terraces in agricultural systems to storm events
    (University of Kansas, 2019-12-31) Stops, Marvin Wes
    Title outlet terrace (TOT) systems have been employed for the last century as a best management practice (BMP) to control surface runoff and associated erosion in agricultural fields. By altering the topography (artificial subsurface drainage and terraces), the hydrology of the landscape is also altered which affects the transformation, transport, and fate of applied fertilizer (nitrogen and phosphorus compounds) and their effect on other solute behavior. The study of storm events in agricultural fields is useful in identifying mechanisms of nutrient transport and transformation during runoff events under varying antecedent soil moisture conditions (pre-event) and varying growing conditions. Here we aim to track the hydrologic response of agroecosystems to storm events in TOTs to elucidate the relationship between hydrology and fertilizer use on chemical weathering fluxes by: 1) separating runoff into matrix, intermediate, and conduit flow using karst hydrology analytical methods; and, 2) pairing these results with measurements of water chemistry to identify mechanisms of nutrient transport and transformation. We focus on TOT’s with constructed wetlands in the Upper Wakarusa watershed to characterize the water flux of storm events in agricultural fields. Stormwater samples were collected directly from tiles coming off three of these TOT agricultural fields and the receiving wetlands constructed to reduce nutrient runoff. Soil water samples were also collected from nested suction-cup lysimeters that are installed at 30, 60, and 90 cm at the ridge top and depression couplet of one terrace at each field site to quantify spatial variability in nutrient concentrations. All water samples were analyzed for total and dissolved nitrogen and phosphorus, total suspended solids, alkalinity, anions and cations. Storm resolved samples (every 30 mins during flow events) from tile outlets (influent storm water) and wetland outlets (effluent wetland water) were collected using automated water samplers. The digital recursive filter approach was used to separate quickflow and baseflow, as exponential fitting and master recession curves approaches failed to partition hydrographs into their components as the discharge did not behave linearly in log-space. Here the proportion of baseflow increased with the amount of incoming precipitation the week prior to the event. Mixing models derived from measured solutes show that Harvest Hills Middle (HHM, the smallest site) was closest to the atmospheric signature while Cain and Harvest Hills North (HHN) had signatures closer to nested lysimeters. This study suggests that higher tile densities led to lower hydrologic flashiness but greater chemodyanmic behavior, specifically addition behavior, and greater weathering fluxes. This was a surprising result as more chemostatic behavior (i.e., invariant solute concentrations with large variations in discharge) was expected. These results demonstrate that there is likely an interactive effect between tile densities and terraces that may lead to non-linear behavior in solute generation and transport compared to just the effect of tiling alone.
  • Publication
    Using Numerical Simulations to Assess Urban Heat Island Mitigation by Converting Vacant Areas into Green Spaces
    (University of Kansas, 2019-12-31) Cady, Timothy John
    Impervious surfaces and buildings in the urban environment alter the radiative balance and energy exchange in the boundary layer, increasing sensible heat flux and decreasing latent heat flux near the surface. This typically results in a positive temperature anomaly known as the urban heat island (UHI). The UHI has been attributed to increases in heat related-illness and mortality. Continued urbanization and anthropogenic warming will enhance the magnitude of UHIs worldwide in the coming decades, raising the need for viable mitigation strategies. Observational studies indicate that green spaces within urban areas can reduce local surface temperature by increasing evaporative cooling and latent heat flux, suggesting that implementing such spaces on a widespread scale may be a viable option to lessen the impacts of the UHI. This work explores the potential impact on the UHI if existing vacant lots are converted to green spaces. The Weather Research and Forecasting (WRF) model was used to simulate the Kansas City, MO region with an inner domain grid spacing of 300 m that allows for block-level analysis. Within WRF, the Single Layer Urban Canopy Model (SLUCM) accounts for the combined radiative effects of natural land cover, vegetation, impervious cover, and building surfaces. Three simulations of summertime heat wave events between 2011 and 2013 are investigated, and model output was validated with surface observations. Using vacant property data and identifying places with a high fraction of impervious surfaces, the most suitable "focus area" for converting vacant lots to green spaces was determined. WRF geographic datasets were modified to simulate varying degrees of realistic conversion of urban to green spaces in these areas. The three control cases under each greening strategy were repeated with the modified geographic datasets, and the local cooling effect using each strategy was compared to each initial control run. Results show that under more aggressive greening strategies, a mean local cooling impact of 0.5 to 1.0 ◦C was present within the focus area itself during the nighttime hours following the development of the stable nocturnal boundary layer. Furthermore, additional cooling via the "park cool island" is of up to 1.0 ◦C possible up to 1 km downwind of the implemented green spaces. Quantifying the thermal impact of converting vacant lots with impervious surfaces to green spaces is an additional factor that can be taken into consideration by policy makers when considering the abatement of the UHI. It is hoped that the focus of this study will serve as guidance to both planners and atmospheric scientists alike as part of the effort to promote future sustainable cities.
  • Publication
    Tracking Multidecadal Lake Water Dynamics with Landsat Imagery and Topography/Bathymetry
    (American Geophysical Union, 2019-10-10) Weekley, David; Li, Xingong
    Water resource management is of critical importance due to its close relationship with nearly every industry, field, and lifeform on this planet. The success of future water management will rely upon having detailed data of current and historic water dynamics. This research leverages Google Earth Engine and uses Landsat 5 imagery in conjunction with bathymetry and Shuttle Radar Topography Mission digital elevation model data to analyze long‐term lake dynamics (water surface elevation, surface area, volume, volume change, and frequency) for Lake McConaughy in Nebraska, USA. Water surface elevation was estimated by extracting elevation values from underlying bathymetry and digital elevations models using 5,994 different combinations of water indices, water boundaries, and statistics for 100 time periods spanning 1985–2009. Surface elevation calculations were as accurate as 0.768 m root mean square error (CI95% [0.657, 0.885]). Water volume change calculations found a maximum change of 1.568 km3 and a minimum total volume of only 23.97% of the maximum reservoir volume. Seasonal and long‐term trends were identified, which have major affects regarding regional agriculture, local recreation, and lake water quality. This research fills an existing gap in optical remote sensing‐based monitoring of lakes and reservoirs, is more robust and outperforms other commonly used monitoring techniques, increases the number of water bodies available for long‐term studies, introduces a scalable framework deployable within Google Earth Engine, and enables data collection of both gauged and ungauged water bodies, which will substantially increase our knowledge and understanding of these critical ecosystems.
  • Publication
    Managing malaria: Selected maps of the twentieth century.
    (University of Kansas, 2007-12-31) Lash, Robert Ryan
    Understanding malaria's geographic occurrence throughout the world is amazingly complex. Jacques May wrote that "a whole atlas, comprising several dozens of maps, could justifiably be devoted to the cartographical representation of what we now know about malaria and its geographical significance." Three themes motivate this work: (1) renewed interest in the occurrence of malaria in Africa, (2) the popularity of research using a Geographic Information System (GIS) to estimate the economic burden of malaria, and (3) an appreciation for the challenges faced when mapping malaria. Selected malaria maps of the 20th century from the World Health Organization (WHO), the American Geographical Society (AGS), and others, are analyzed to identify the way maps are used to communicate information about malaria. Conclusions are drawn about the use of GIS for mapping malaria, and an argument for the importance of cartographically informed GIS users is made.
  • Publication
    Regional flow conditions associated with stratocumulus cloud-clearing events over the southeast Atlantic
    (University of Kansas, 2019-08-31) Tomkins, Laura M
    Large, abrupt clearing events have been documented in the marine stratocumulus cloud deck that resides over the subtropical Southeast Atlantic Ocean. In these events, clouds are rapidly eroded along a line hundreds–to–thousands of kilometers in length that generally moves westward away from the African coast. Because marine stratocumulus clouds exert a strong cooling effect on the planet, any phenomenon that acts to erode large areas of low clouds may be climatically important. Previous satellite-based research has suggested that the cloud-clearing events may be caused by westward-propagating atmospheric gravity waves rather than simple advection of the cloud boundary. The gravity waves are hypothesized to be excited by an interaction between offshore flow from the African continent and the stratocumulus-topped marine boundary layer. The Weather Research and Forecasting (WRF) model is used to explore the nature of the offshore flow, which is a fundamental physical mechanism behind the dramatic clearing events. Results are presented from two series of week-long simulations driven by ERA–Interim reanalysis in the month of May when cloud-clearing boundaries exhibit maximum frequency. One series covers a period containing multiple cloud-clearing episodes (active period), and the second series covers a period without any cloud-clearing episodes (null period). Synoptic analysis, Hovmöller diagrams, and passive tracers are used to assess the character of the diurnal west-African coastal circulation. Our results indicate that the active period regularly experiences offshore flow from the continent above the boundary layer overnight, whereas the null period is associated with predominantly onshore flow along the coast particularly in the afternoon. The offshore flow overrunning the boundary layer can extend hundreds of kilometers westward of the coast. We document 900-hPa disturbances in each period, which influence the coastal flow of the region. Additionally, we find that the boundary layer height is higher in the null period than in the active period, suggesting that the active periods are associated with areas of thinner clouds that may be more susceptible to cloud-clearing events.
  • Publication
    Pipelines, Protectors, and a Sense of Place: Media Representations of the Dakota Access Pipeline Protest
    (University of Kansas, 2019-05-31) Grote, Katie
    Indigenous resistance to the construction of the Dakota Access Pipeline (DAPL) garnered national and international media attention in 2016 as thousands gathered near the Standing Rock Sioux Reservation in protest. Increased media attention spurred enquiry concerning the representation of the Indigenous peoples leading the movement. The majority of the U.S. population is ill-informed about historical and contemporary issues concerning Indigenous peoples; this limited understanding of Indigenous experience is manifest in news outlets and their audiences’ knowledge of current issues impacting Indigenous peoples. This research employs a qualitatively-based content analysis of 80 news articles reporting on the DAPL protest. These articles range in political bias and can be categorized in one of the following groups: Conservative Bias, Liberal Bias, Mainstream News, Local News, and Indigenous News. Commonly occurring codes and themes are analyzed across each category. Word count and frequency of reporting are also considered to gain a more comprehensive understanding of the media representations as they develop through time. While the non-Indigenous-led media commonly cites water security and destruction of sacred sites as the reasons for protest, the Indigenous led media also cites treaty rights, tribal sovereignty, economic vulnerability, climate change, and colonial history more frequently, indicating a more holistic understanding of the movement and the Indigenous experience. The mainstream of U.S. reporting on the DAPL protests perpetuate settler ignorance concerning the daily struggles of Indigenous Americans by ignoring the associated political and economic realities of these communities.
  • Publication
    Socio-Environmental Impacts of Argentine Yerba Mate Cultivation: “El Problema es el Precio Bajo”
    (University of Kansas, 2019-05-31) Dohrenwend, Adam Scott
    Consumption in today’s globalized economy makes it difficult to understand the consequences of our actions across the globe. A political-ecological lens, informed by the work of Robert Sack and Ian Cook, can help guide an analysis that geographically reconstructs supply chains and reveals the realities of consumption. This thesis applies this approach to study the externalization of cost under capitalism in the production of Argentine yerba mate, an infusion with stimulant properties long-used by indigenous peoples. The use of yerba mate has become a cornerstone of Argentine society and identity, and yerba mate processors are working to expand exports globally. In Argentina’s Misiones province, the heart of yerba mate production, the true costs of production are borne by the children, the impoverished laborers, and the environment of Argentina’s Atlantic Rainforest. These consequences of modernity, along with the efforts of an NGO to remedy them, are presented and assessed.
  • Publication
    Ouray Postcard Sense-of-Place: Looking at Words and Reading Pictures
    (University of Kansas, 2019-05-31) Willis, Stephanie Rae
    To modernize sense-of-place research methods and restore humanistic depth to the field of geography, this research is an exploration into inventive tools and techniques for sense-of-place investigations. A historical postcard GIS was built and analyzed to assess sense of place for Ouray, Colorado. Another GIS was constructed using the results of a Ouray local self-directed photography exercise. These data were analyzed as well to reflect upon the effectiveness of alternative sense-of-place methodologies. This research demonstrates the possibilities for integrating geospatial technologies into qualitative geographic research.
  • Publication
    Structural diversity and ecosystem-resource relationships in tropical savanna and a legume-cereal intercrop
    (University of Kansas, 2019-05-31) Nosshi, Maged Ikram
    While the most productive ecosystems on Earth, correspondingly the most diverse, function within limitations of energy and resource flows, the general approach of high-yielding agriculture, in contrast, has been to simplify and replace key ecosystem functions with non-renewable inputs. Restoring ecological processes in agriculture requires some understanding of the underlying mechanisms. Here, I explore a unifying framework regarding the coupling between ecosystem structure and function. Namely, that the capacity of water-limited ecosystems to optimize water use, or resist stress is a product of their life-form diversity. I apply this hypothesis to infer the response of structurally contrasting ecosystems at a wide range of scales: (i) At the plot scale, I test the role of resource complementarity (“niche-based” mechanisms) in a perennial grain-legume intercrop, using stable isotope analysis. (ii) At the sub-continental scale, I use satellite data to explore the response of one of the most variable terrestrial biomes, tropical savanna, to rainfall variability. I employ different approaches to demonstrate the degree of coupling between ecosystem response and the environmental forcing. The dissertation concludes by summarizing the key findings and outlining further work needed to explore the role of ecosystem structure on function in water-limited systems. I discuss the implications of niche complementarity on resource relationships of biologically diverse agroecosystems, emphasizing the need for a re-evaluation of the conceptual framework used to envision niche complementarity to account for alternative resource acquisition pathways. I explore the role of savanna hydrophenology as a stabilizing mechanism, relating patterns of synchrony to savanna structure and composition. The relevance of this work is directly linked to the loss of ecological function which manifests in agriculture’s growing dependence on fossil energy to mask diminishing returns from extractive use of land and water resources. Enriched knowledge of potential mechanisms, coupling structural diversity with ecosystem function, in both natural and managed ecosystems, will provide insight into the ecological basis for diversity driven processes in water-limited ecosystems.
  • Publication
    Archaeological predictive model of southwestern Kansas
    (University of Kansas, 2006-12-31) Campbell, Joshua Stewart
    Knowledge on the archaeological condition of southwestern Kansas is anomalously low, therefore a high-resolution archaeological predictive model has been constructed for the High Plains region of southwestern Kansas. Using quantitative data about the environment as independent variables, the model was constructed using a combination of Geographic Information Systems (GIS) and statistical software. The location of sites was quantitatively related to the environment through a binary logistic regression analysis. The derived regression equation was used to create a unique probability score for each of the 20 million land parcels in the study area. Analysis indicates the model offers a significant increase (30%) over a random classification. 85% of known site locations and 60% of known non-site locations are accurately predicted. In total, the area predicted as site-present comprises 41% of the total study area; within which, the chances of finding a site are 2.15 times as likely as random.
  • Publication
    In Our Country, but Outside Our Homeland: Identity and Diaspora Among Ukraine’s Internally Displaced Crimeans
    (University of Kansas, 2018-12-31) Charron, Austin L
    In response to Russia’s annexation of the Crimean Peninsula in 2014, tens of thousands of Crimean residents have relocated to mainland Ukraine as Internally Displaced Persons (IDPs), including many ethnic Ukrainians, Russians, and indigenous Crimean Tatars. Deliberately choosing to remain Ukrainian rather than Russian citizens, Crimean IDPs have become emblematic of new discourses of Ukrainian civic and multicultural nationalism emerging in the wake of the 2013-2014 Euromaidan protests. While they are proud Ukrainian patriots, most Crimean IDPs also maintain a strong sense of regional identity tied to Crimea itself, and therefore understand themselves to be simultaneous “in place” and “out of place” within the Ukrainian mainland. This disjunctive sense of territorial belonging bears most of the hallmarks of a diasporic condition, except for the presumption of international migration that undergirds normative “transnational” theories of diaspora. Showcasing Crimean IDPs as a salient case study, this dissertation advances an alternative “translocal” theory of diaspora that is attentive to discourses of belonging and exclusion whether or not migrants have crossed an international border. Relying on ethnographic fieldwork conducted within Crimean IDP communities in the cities of Kyiv and Lviv, this dissertation traces the motivating factors driving internal displacement from occupied Crimea, unpacks the Ukrainian and Crimean identities that dialectically animate IDPs’ schismatic senses of territorial belonging, and analytically situates their varied experiences within a diasporic framework, disrupting the problematic epistemological binary of internal/international migration that hampers theories of diaspora.
  • Publication
    Rethinking the Scales of Eurasia: Geopolitical Narratives and Borders in Ukraine
    (University of Kansas, 2018-12-31) Biersack, John
    Geopolitics relies on discursive constructions of world affairs to forge privileged meanings in the service of particular aims involving spatial relations. This study interrogates how geographical scale is used to spatialize politics and imagine and advantage agendas using scalar narratives of Eurasia regarding Ukraine in 2014-15. The politics of scale situates the borders of Eurasia within Ukraine. Critical scholarship emphasizes how discourses and scales are performatives, establishing an iterative hegemony through repetition. The dissertation uses a comparative, qualitative discourse analysis framework to interrogate how Eurasia functions as a scale linking places, peoples, and things using texts from discursively marginal and mainstream geopolitical discourses. The relationship between the mainstream discourse of the Presidential Administration of the Russian Federation and the marginal discourses of the self-proclaimed government of the Donetsk People’s Republic, and the Russian nationalism of neo-Eurasianist thinker Aleksandr Dugin are compared using the annexation of Crimea and war in eastern Ukraine (Donbas) as discursive events. Eurasia in scalar narratives shows the hierarchical and relational facets of scale as a concept. The conceptual intertextuality of Eurasia and the Russian World is manifested in the three discourses. Russian official discourse and nationalist discourse frame the annexation of Crimea as less-than-national and more-than-national scales. The conflict in eastern Ukraine is situated in the discourses as less-than-national through the use of Novorossiya. Novorossiya is also scaled up; Eurasia provides a nodal point offering forms of legitimacy for the Donetsk People’s Republic and the nationalist discourse of neo-Eurasianism. The scalar narratives of the nation-state are threatening and the West is a source of disorder. Eurasia acts as a nodal point, connecting and making equivalent scalar processes and the borders of Eurasia in Ukraine.
  • Publication
    A Paleosol-Derived Environmental Perspective on MIS 3 in the Central Great Plains
    (University of Kansas, 2018-08-31) Burt, Dakota James
    The Marine Isotope Stage (MIS) 3 Gilman Canyon Formation (GCF) is a unique stratigraphic unit prevalent throughout the Central Great Plains of North America and serves as an important underutilized archive of paleoenvironmental data. This study focuses on the GCF in central Kansas where it contains two cumulic paleosols and an intervening detrital unit, which have been radiocarbon dated ~46 ka to 24 ka, a period that spans most of MIS 3. Herein, newly obtained stable isotope, elemental, enviromagnetic, phytolith, particulate charcoal, particle size, color, and observational data from the GCF are used to generate the most comprehensive look at the MIS 3 environment in the Central Great Plains to date. In the distal portion of the Central Great Plains loess plume the GCF supported a moderately active soil community dominated by C4 grass prairies, suggesting a warm fairly dry climate prevailed during most of MIS 3.
  • Publication
    EFFECTS OF GREENSPACE CONFIGURATION ON THE URBAN HEAT ISLAND: A STUDY OF THE KANSAS CITY METROPOLITAN AREA
    (University of Kansas, 2018-05-31) Wesley, Elizabeth Jane
    To investigate the relationship between greenspace pattern and UHIs we conducted a multi-resolution wavelet analysis of land surface temperature (LST) to determine the dominant length scales of LST. We used these scales as extents for calculating landscape metrics on a high-resolution landcover map. We built regression models to investigate whether, controlling for the percent vegetated area, patch size, fragmentation, shape, complexity, and/or proximity can mitigate UHIs. We found that more and complex patches of greenspace and dispersed rather than clustered greenspace can effectively mitigate UHIs. We also found that the negative relationship often reported between patch size and LST is an artifact of the relationship between increased percent vegetated and LST. By using the dominant length scales of LST we demonstrate that aggregation and shape complexity are important configuration factors to consider in designing urban greenspace and provide a methodology for robust biophysically-based analysis of urban landscape pattern.
  • Publication
    Climatology of the San Francisco Bay and the Initiation of Wind Reversals along the Western United States Coast Determined from AMDAR Data
    (University of Kansas, 2018-05-31) Turner, Dillon Seaber
    Observations from commercial aircraft through the Aircraft Meteorological Data Relay (AMDAR) automated weather reports provide a higher frequency sampling of the lower atmosphere than the twice daily radiosonde launches performed by the National Weather Service. In the San Francisco Bay area, the number of profiles from flights arriving or departing San Francisco International Airport (SFO), Oakland International Airport (OAK), and San Jose International Airport (SJC) have increased dramatically from 2001 to 2016. Low-level features in the coastal margins are difficult to simulate, so AMDAR opens up new possibilities to investigate coastal phenomena. This study uses AMDAR measurements from 2001-2016 in the bay area and focuses on three main objectives: (1) understanding the AMDAR climatology of the lower atmosphere in the bay area, (2) examining the effectiveness of AMDAR data to identify and quantify precursors to wind reversals along the central California coast, and (3) use the quantified magnitudes of the precursors to forecast wind reversals. A limiting factor in past studies of wind reversals was the lack of long-term monitoring of the lower atmosphere. While soundings from the aircraft at OAK and SFO were similar and more influenced by the marine environment, SJC had more continental features. Significant anomalies of temperature and wind occurred more than 24 hours ahead of the passage of a wind reversal. A forecast metric was developed using the anomalies, but the metric was not skillful.​
  • Publication
    Using GIS and historical flood data to analyze the risk and vulnerability of a rural community, past and present: The Neosho River in Coffey County, Kansas
    (University of Kansas, 2018-05-31) Mays, Cara
    Flooding is among the most destructive natural disasters. Continuous monitoring of potential flooding is necessary for decision makers and planners. Using GIS, analysis and visual representation allow for vulnerable areas to be identified and analyzed for risk. If potential flood risk areas can be identified, assessed, and understood, then minimizing the damage to properties and saving lives can increase. Coffey County, Kansas is located in east-central Kansas and is home to 8,500 people, Wolf Creek Nuclear Operating Corporation, and John Redmond Reservoir. With the construction of John Redmond, flooding has significantly decreased, but the flood history of this county still looms. Coffey County’s topographic characteristics make the location ideal for flood risk assessment as the city of Burlington lies along the Neosho River, protected upstream by a reservoir. Although the likelihood of a historic flood, like the one Burlington experienced in 1951, is minimal, being prepared should be, and is, a priority for all of Coffey County. This research emphasizes the importance of defining an area’s critical infrastructure, locating these areas, and assessing their potential flood risk. This information is vital to the awareness and preparedness of a community. Obtaining and simulating historical flood data allows for viewers to visualize the potential risk to their homes, infrastructure, and population. Using GIS analysis tools, visual representations were produced that can be used by emergency responders, city planners, and other decision makers to aid in creating and utilizing a flood risk assessment and response plan for the community.
  • Publication
    Relating Urban Morphology and Urban Heat Island During Extreme Heat Events in the Kansas City Metropolitan Area
    (University of Kansas, 2018-05-31) Chai, Rodney M
    Satellite images offer continuous spatial and temporal coverage of surface temperature, thus allowing us to transcend limitations of in-situ measurements and giving us a powerful tool to understand the Urban Heat Island (UHI). This study uses MODIS Land Surface Temperature (LST) at 1 km to examine the relationship between urban morphology and UHI. Using the Kansas City metropolitan area as a case study, we examined MODIS LST data during the summer months of 2002-2017. We found that LST anomalies increase exponentially from 1.5°C at the 90-95 percentile to 3.5°C at the 95-100 percentile. In particular, natural land cover LCZ classes are found to have higher LST anomalies than built-type LCZ classes by up to 5°C. Results suggest that the higher LST anomalies over outlying areas are not due to suburban development during the most extreme heat episodes. We also examined the utility of the LCZ scheme during extreme heat events. We found that the LST response is not statistically different between the various LCZ classes and that the local built environment is not as important in predicting the LST response to increasingly extreme heat events. However, the LST response by most LCZ classes as a function of distance from downtown is statistically significant, with values ranging from -0.08°C/km to -0.01°C/km. The results show that the distance from the city center plays a more important role in helping predict LST response than knowledge of the LCZ class.
  • Publication
    QUANTITATIVE CHARACTERIZATION AND PEDOGENIC DEVELOPMENT OF SOIL STRUCTURE
    (University of Kansas, 2018-05-31) Mohammed, Aoesta Khalid
    Soil particles are often arranged into repeating patterns of aggregates with similar shapes, sizes, and degrees of expression. These repeating aggregates, known as ‘peds,’ are currently described using qualitative and subjective categories for type, size, and grade as follows. Peds are assigned a type class (e.g., platy, granular, prismatic, etc.) based on overall ped shape. Peds are classified into size categories (e.g., fine, medium, and coarse) based on quantitative ped width and thickness criteria. Peds are assigned a grade class (e.g., weak, moderate, or strong) which describes the degree of expression. Soil structure develops as a result of complex interactions with climate, organisms, relief, parent material, and time. However, our understanding of these interactions is limited by the categorical and subjective nature of ped descriptions and the lack of datasets that include a wide range of variability in the factors responsible for the development of soil structure. Therefore, the first objective of this dissertation was to develop a method to quantify soil structure using morphometric indices for ped shape by analyzing previously published digital photographs of soil profiles and structural specimens. The second objective of this dissertation was to assemble an easily-accessible, two-dimensional data matrix containing laboratory and field-based measurements of soil properties across the USA and integrate topographic, climatological, and ecological data to, ultimately, explore the response of soil structure to exogenous and endogenous factors in both surface A horizons and subsurface B horizons. To those ends, we assembled two databases: the Ped Shape Digital Morphometric (PSDM) database and the University of Kansas Research Dataset of Soils (KURDS). The PSDM database was used to develop new morphometric indices of ped silhouettes quantitatively describing ped shape. These morphometric indices were applied to a subset of KURDS and used in conjunction with multinomial logistic regression and decision tree analyses of qualitative ped data to explore endogenous and exogenous controls on the development of soil structure. We found that the exogenous factor, climate, exhibited the greatest control over ped shape and size whereas clay content (endogenous) was the most important factor predicting ped grade. The finding that climate exhibits control over the evolution of soil structure represents an unexplored avenue for understanding how global climate change will affect morphological properties that control soil hydrology. Overall, this dissertation demonstrates the possibilities of describing peds in terms of quantitative variables and analyzing continental-scale databases of soil structure.
  • Publication
    Influence of Grassland Heterogeneity on Land-Atmosphere Coupling
    (University of Kansas, 2018-05-31) Logan, Kelly
    Land surface processes and interactions with the atmosphere have been identified as a weak point in our understanding of the Earth's climate system and contribute to uncertainty in projections of future climate. This weakness is due, in part, to the inherent complexity of land-atmosphere (LA) interactions and the highly heterogeneous nature of land cover across a variety of spatial and temporal scales. The research included in this dissertation looks at the significance of these issues over a central US grassland. Influence of spatiotemporal variability is investigated through comparison between two proximate grassland sites with differing land cover. High-frequency observations from eddy covariance towers over a study period covering a range of environmental forcings, including two strong droughts and woody encroachment at one site provides a unique opportunity for study. First, changes in the water, energy, and carbon budgets are studied, with focus on the influence of woody encroachment on carbon sequestration, water-use efficiency, and drought response. How these changes manifest in the nature of turbulent fluxes, including at which spatial and temporal scales, are invested through deviations from similarity theory, quadrant analysis, and wavelet decomposition. Second, the nature of coupling between the land surface and atmosphere is studied by utilizing a variety of LA feedback metrics and analysis tools that allow for investigation of several steps in the LA feedback chain. This research includes the first use of some of these tools (self-organizing maps and mixing diagrams) in an study of this nature. Results indicate that woody encroachment increases resilience to drought due to changes in canopy structure and root access to soil moisture, and highlight the need to carefully consider scale and objective when selecting a metric of LA coupling.