A geographically weighted regression approach to understanding urbanization impacts on urban warming and cooling: a case study of Las Vegas

A surface urban heat island (SUHI) effect is one of the most significant consequences of urbanization. Great progress has been made in evaluating the SUHI with cross-sectional studies performed in a number of cities across the globe. Few studies; however, have focused on the spatiotemporal changes in an area over a long period of time. Using multi-temporal remote sensing data sets, this study examined the spatiotemporal changes of the SUHI intensity in Las Vegas, Nevada, over a 15-year period from 2001 to 2016. We applied the geographically weighted regression (GWR) and advanced statistical approaches to investigating the SUHI variation in relation to several important biophysical indicators in the region. The results show that (1) Las Vegas had experienced a significant increase in the SUHI over the 15 years, (2) Vegetation and large and small water bodies in the city can help mitigate the SUHI effect and the cooling effect of vegetation had increased continuously from 2001 to 2016, (3) An urban heat sink (UHS) was identified in developed areas with low to moderate intensity, and (4) Increased surface temperatures were mainly driven by the urbanization-induced land conversions occurred over the 15 years. Findings from this study will inspire thoughts on practical guidelines for SUHI mitigation in a fast-growing desert city

The Spatial and Temporal Characteristics of the Urban Thermal Environment in East Africa: Implications for Sustainable Urban Development

Targeting cities in East Africa, where urbanisation and climate change are posing unprecedented threats to livelihoods and ecosystems, this thesis focuses on the combined effects of rapid urbanisation and climate change on Land Surface Temperature (LST), Surface Urban Heat Island (SUHI) effects and the role of Blue Green infrastructure (BGI) and vegetation dynamics. The aim of this thesis is to advance understanding of the urban thermal environment and the role of factors such as climate, vegetation and urbanisation patterns that add to its complexity. Through the use of satellite and remote sensing data (e.g., Google Earth Engine), spatial and statistical analyses, conducted in ArcGIS, Geoda and R, this thesis provides analyses of temporal trends between 2003 and 2017, and spatial differences in LST and SUHI in five East African cities (Khartoum, Addis Ababa, Kampala, Nairobi, Dar es Salaam). It advances understanding of how the configuration of urban areas affects the urban thermal environment, the amount of vegetation and surface water, and demonstrates the influence of urban density on the changes in SUHI intensity in both space and time. By linking the findings from the three results chapters and placing this in the context of the broader literature, corresponding policy implications and solutions are presented. The urgent need to provide a more detailed understanding of urban thermal environments, including macroclimate differences, seasonal variation and urban morphological characteristics, is highlighted. Recommendations emphasise the use of cloud-based analysis methods to overcome data scarcity, while the results point towards the utility of nature-based solutions for urban sustainable development. The methods and lessons emerging from this study can also be applied in other rapidly urbanising cities, where climate change is posing an unprecedented threat to livelihoods and ecosystems, and where resources are limited

Urban vegetation : towards cooler, biodiverse cities of the future

This thesis presents my doctoral research programme that aims to increase the understanding of the role that vegetation plays in functional urban ecosystems. To do this, I have systematically evaluated: (1) relationships between tree canopy traits and associated subcanopy cooling; (2) how planting context (e.g., parks or streets) influences the ability of trees to provide cooling benefits; (3) how canopy-associated cooling is influenced by ambient climatic conditions (solar radiation, vapor pressure deficit (VPD) and wind speed); and (4) how habitat/vegetation complexity influences invertebrate biodiversity, in urban settings across Greater Sydney. Whilst there has been some research exploring relationships between vegetation and landscape traits and urban temperature profiles, to date no study has systematically evaluated how different planting contexts, such as parks, nature strips or pavement/tarmac settings, influence the ability of trees to provide cooling benefits in the local environment. To address this gap, my research identifies those traits that determine the cooling potential of urban trees, alongside the impacts of planting context on the ability of trees to reduce air and surface temperatures. The first data chapter presents the results of a study across Greater Sydney that found tree shade reduced air and surface temperature by a maximum of 3.7 °C (mean 1.1 °C) and 45 °C (mean 27.4 °C), respectively. The magnitude and variability of tree-derived cooling benefits differ greatly among studies, likely reflecting differences in tree species’ traits, urban characteristics and local climate conditions. The second data chapter presents findings from a systematic study focused on ten commonly occurring species in western Sydney. In addition to the cooling benefits provided by trees, urban vegetation also provides other critical ecosystem services, including habitat and resources for a diverse range of vertebrate and invertebrate animal species. For example, an invertebrate-rich environment xi contributes to food security, nutrient cycling and pest control. Systematic explorations of the association between habitat/vegetation complexity and invertebrate biodiversity in urban areas are limited. My third data chapter therefore examined whether and how trees and shrubs differ in terms of the diversity, abundance and composition of associated invertebrate communities. Overall, my thesis research provides valuable new insights into the extent of cooling benefits provided by a variety of tree species in urban areas throughout Greater Sydney, and how these are influenced by tree canopy traits and local environmental conditions

The Built Environment in a Changing Climate

The papers included in this Special Issue tackle multiple aspects of how cities, districts, and buildings could evolve along with climate change and how this would impact our way of conceiving and applying design criteria, policies, and urban plans. Despite the multidisciplinary nature of the collection, some transversal take-home messages emerge: • Today’s energy-efficient paradigms may lose their virtuosity in the future unless accurate estimates of future scenarios are used to design modelling platforms and to inform legislative frameworks; • Acting at the local scale is key. Future climate change adaptation will be implemented at the local level. Overlooking regional and local specificities will contribute to inaccurate and inefficient action plans. As such, the smaller scale will become vital in predicting future urban metabolic rates and corresponding comfort-driven strategies; • Energy poverty, heat vulnerability, and social injustice are emerging as critical factors for planning and acting for future-proof cities on par of micro- and meso-climatological factors; • Given that the impacts of climate change will persist for many years, adaptation to this phenomenon should be prioritized by removing any prominent barrier and by enabling combinations of different mitigation technologies. These topics will receive a global reach in few decades, since also developing and underdeveloped countries are starting their fight against local climate change, with cities at the forefront

Outdoor Wellbeing and Quality of Life: A Scientific Literature Review on Thermal Comfort

While indoor comfort represents a widely investigated research topic with relation to sustainable development and energy-demand reduction in the built environment, outdoor comfort remains an open field of study, especially with reference to the impacts of climate change and the quality of life for inhabitants, particularly in urban contexts. Despite the relevant eorts spent in the last few decades to advance the understanding of phenomena and the knowledge in this specific field, which obtained much evidence for the topic\u2019s relevance, a comprehensive picture of the studies, as well as a classification of the interconnected subjects and outcomes, is still lacking. This paper reports the outcomes of a literature review aimed at screening the available resources dealing with outdoor thermal comfort, in order to provide a state-of-the-art review that identifies the main topics focused by the researchers, as well as the barriers in defining suitable indexes for assessing thermal comfort in outdoor environments. Although several accurate models and software are available to quantify outdoor human comfort, the evocated state of mind of the final user still remains at the core of this uncertain process

THE COMPLEXITIES IN INEQUITIES: APPLYING CRITICAL ENVIRONMENTAL JUSTICE STUDIES TO URBAN GREEN INFRASTRUCTURE DEVELOPMENT

Many cities have turned to urban green infrastructure (UGI) to combat water pollution and urban heat island effect (UHIE). UGI is a multifunctional and serves multiple purposes to residents and the surrounding urban environment. For example, street trees not only provide temperature control for UHIE, but also provide housing for non-human species and as recreation for residents or urban agriculture has a positive effect on decreasing UHIE, but also effectively contributes to food sovereignty. This research aims to critique UGI development in the United States using David Naguib Pellow’s Critical Environmental Justice Studies framework. I will evaluate different UGI features, using his four pillars: intersectionality, multiscalar, the state and indispensability to understand how injustices occur within development. This research was conducted due to the seemingly lack of involvement of racialized people in the planning process. There is a continuous stress of developing more greening across the country, but usually does not account for the impacts it will have on vulnerable communities such as racialized people

Effects of urbanization on regional meteorology and air quality in Southern California

Urbanization has a profound influence on regional meteorology and air quality in megapolitan Southern California. The influence of urbanization on meteorology is driven by changes in land surface physical properties and land surface processes. These changes in meteorology in turn influence air quality by changing temperature-dependent chemical reactions and emissions, gas–particle phase partitioning, and ventilation of pollutants. In this study we characterize the influence of land surface changes via historical urbanization from before human settlement to the present day on meteorology and air quality in Southern California using the Weather Research and Forecasting Model coupled to chemistry and the single-layer urban canopy model (WRF–UCM–Chem). We assume identical anthropogenic emissions for the simulations carried out and thus focus on the effect of changes in land surface physical properties and land surface processes on air quality. Historical urbanization has led to daytime air temperature decreases of up to 1.4&thinsp;K and evening temperature increases of up to 1.7&thinsp;K. Ventilation of air in the LA basin has decreased up to 36.6&thinsp;% during daytime and increased up to 27.0&thinsp;% during nighttime. These changes in meteorology are mainly attributable to higher evaporative fluxes and thermal inertia of soil from irrigation and increased surface roughness and thermal inertia from buildings. Changes in ventilation drive changes in hourly NOx concentrations with increases of up to 2.7&thinsp;ppb during daytime and decreases of up to 4.7&thinsp;ppb at night. Hourly O3 concentrations decrease by up to 0.94&thinsp;ppb in the morning and increase by up to 5.6&thinsp;ppb at other times of day. Changes in O3 concentrations are driven by the competing effects of changes in ventilation and precursor NOx concentrations. PM2.5 concentrations show slight increases during the day and decreases of up to 2.5&thinsp;µg&thinsp;m−3 at night. Process drivers for changes in PM2.5 include modifications to atmospheric ventilation and temperature, which impact gas–particle phase partitioning for semi-volatile compounds and chemical reactions. Understanding process drivers related to how land surface changes effect regional meteorology and air quality is crucial for decision-making on urban planning in megapolitan Southern California to achieve regional climate adaptation and air quality improvements.</p

Categorización de las manzanas urbanas para la integración de la silvicultura urbana en la planificación de las ciudades. Caso de estudio: Área Metropolitana de Mendoza, Argentina

La urbanización es uno de los principales factores antropogénicos que ha causado la reducción de la superficie verde y la sustitución de los hábitats preexistentes en las ciudades. En la actualidad, más de la mitad de la población humana mundial se concentra en zonas urbanas y la región de américa latina es una de las más urbanizadas del mundo, con el 80% de su población en las ciudades y un deterioro progresivo en aspectos energético-ambientales. El objetivo futuro es determinar estrategias de intervención que posibiliten alcanzar mejoras en los valores de actividad fotosintética vegetal en ciudades forestadas de la región insertas en clima seco. El trabajo ha permitido una categorización del índice de vegetación de diferencia normalizada (NDVI) en las manzanas urbanas del Área Metropolitana de Mendoza (AMM) a partir de sistemas de información geográfica (SIG) y del análisis de imágenes satelitales Landsat 8. Los resultados obtenidos indican un vigor vegetativo nulo o bajo del 39.87% en las manzanas del AMM y moderado del 45.47%. La categorización de las manzanas, ha permitido además un análisis estadístico preliminar por departamento considerando las estaciones otoño-invierno y primavera-verano. En el AMM el NDVI anual del 52.08% de las manzanas urbanas de Godoy Cruz se ubican en el rango nulo o bajo; seguido por Guaymallén 48.24% y Maipú 45.61%.  La gobernanza eficiente de las ciudades en la región requiere de políticas proactivas, planificación estratégica y legislación que integren la silvicultura urbana. El trabajo aporta conocimiento de base, necesario para un enfoque integrado de sostenibilidad.El desarrollo de esta investigación contó con el financiamiento de los proyectos PPI-FAUD-Universidad de Mendoza; PIP11220130100407 (CONICET); UE CONICET 2017- 2022/22920170100036. Algunas imágenes han sido procesadas y elaboradas con la colaboración de M. Fontanive (Politecnico di Torino), C. Cucchietti y J. Morales (Universidad de Mendoza), como parte de prácticas profesionales supervisadas realizadas en INCIHUSA-CONICET.Arboit, ME.; Maglione, DS. (2020). Categorización de las manzanas urbanas para la integración de la silvicultura urbana en la planificación de las ciudades. Caso de estudio: Área Metropolitana de Mendoza, Argentina. En III Congreso Internacional ISUF-H. CIUDAD COMPACTA VS. CIUDAD DIFUSA. Editorial Universitat Politècnica de València. (20-05-2020):297-305. https://doi.org/10.4995/ISUFh2019.2019.9938OCS29730520-05-202

中国における都市化総合評価及び環境への影響に関する研究

In Chapter one, research background and significance is investigated. In addition, previous studies and current situation in the research fields was reviewed and discussed. In Chapter two, an in-depth review of prior studies associated with the research topic was conducted. The literature review was carried out from three aspects: urbanization and eco-environment evalution and coordination, urban sprawl assessment and urban heat island investigation. In Chapter three, maximum entropy method was applied to help generate the evaluation system of eco-environment level and urbanization level at provincial scale. Comparison analysis and coordinate analysis was carried through to assess the development of urbanization and eco-environment as well as the balance and health degree of the city develops. In Chapter four, DMSP/OLS stable nighttime light dataset was used to measure and assess the urban dynamics from the extraction of built up area. Urban sprawl was evaluated by analyzing the landscape metrics which provided general understanding of the urban sprawl and distribution pattern characteristics could be got from the evaluation. In Chapter five, the investigation of surface urban heat island effects in Beijing city which derive from land surface temperature retrieval from remote sensing data of Landsat TM was carried out. In addition, spatial correlation and relationship between the urbanization level, vegetation coverage and surface urban heat island was carried out in this chapter. In Chapter six, all the works have been summarized and a conclusion of whole thesis is deduced.北九州市立大