No description available.

Coral reef recovery following a disturbance relies heavily on the restoration of coral cover, via growth of existing colonies and the successful recruitment of new corals. In well-connected reef networks, recruits may be sourced from neighboring reefs. In contrast, coral recruitment on geographically isolated reefs is reliant on adult corals at that location, which may limit recovery rates following mass coral mortality events. Such mortality events are increasingly caused by climate change induced temperature anomalies, which are overlaid on the local chronic human disturbances that already affect most of the world’s coral reefs. In this thesis, I exploit a natural ecosystem-scale experiment to examine how multiple anthropogenic stressors impact densities of coral recruits and small corals (e.g., juveniles; 5 cm) on Kiritimati (Christmas Island, Republic of Kiribati), an isolated atoll in the central equatorial Pacific Ocean. Specifically, I used benthic survey videos from before, during, and one year following the 2015-2016 El Niño and coral settlement tiles deployed during the three years after the event at 22 sites across the island, to quantify small corals and coral recruits, respectively. Local chronic stress negatively impacted small corals, with densities 47% lower at sites exposed to very high levels of chronic stress prior to the heat stress. The El Niño further resulted in a 56% loss of small corals, particularly for competitive coral species. Following the event, stress tolerant small corals rebounded to pre-El Niño densities within a year, whereas competitive and small corals overall had non-significant increases. I also quantified a low recruitment rate of 8.31 recruits m-2 per year (± 1.9 SE) during the three years following the El Niño compared to previous studies around the Pacific; recruits were genetically identified as primarily belonging to the stress tolerant family Agariciidae and the competitive genus Pocillopora. Local human disturbance also impacted coral recruitment with densities significantly lower at those with the greatest local chronic disturbance, together suggesting that local disturbance impedes post-settlement survival of recruits and the resilience of young corals during acute stress events. With increased net primary productivity, densities of both small corals and recruits (non-significant) also increased, which could reflect the positive influence of coral heterotrophic nutrition supplements during and after stress events, increasing survivability. Despite very low overall coral recruitment, all island regions did have some recruits, but Vaskess Bay (a bay region on the southern part of the island) had the highest densities. Overall these results indicate the negative consequences combined chronic and acute stressors can have on coral recruits, small corals, and accompanying coral resilience. When viewed together, this work suggests how the resilience is compromised by chronic stressors on Kiritimati and that the recovery trajectory may be variable across the disturbance gradient. Thus, local reef management may provide an avenue for enhancing recovery rates as acute temperature anomalies increase in frequency under our current climate trajectory. / Graduate / 2021-01-14

abstract: Thermal extremes are responsible for more than 90% of all weather-related deaths in the United States, with heat alone accounting for an annual death toll of 618. With the combination of global warming and urban expansion, cities are becoming hotter and the threat to the well-being of citizens in urban areas is growing. Because people in modern societies (and in particular, vulnerable groups such as the elderly) spend most of their time inside their home, indoor exposure to heat is the underlying cause in a considerable fraction of heat-related morbidity and mortality. Notably, this can be observed in many US cities despite the high prevalence of mechanical air conditioning in the building stock. Therefore, part of the effort to reducing the overall vulnerability of urban populations to heat needs to be dedicated to understanding indoor exposure, its underlying behavioral and physical mechanisms, health outcomes, and possible mitigation strategies. This dissertation is an effort to advance the knowledge in these areas. The cities of Houston, TX, Phoenix, AZ, and Los Angeles, CA, are used as test beds to assess exposure and vulnerability to indoor heat among people 65 and older. Measurements and validated whole-building simulations were used in conjunction with heat-vulnerability surveys and epidemiological modelling (of collaborators) to (1) understand how building characteristics and practices govern indoor exposure to heat among the elderly; (2) evaluate mechanical air conditioning as a reliable protective factor against indoor exposure to heat; and (3) identify potential impacts from the evolving building stock and a warming urban climate. The results show strong associations between indoor heat exposure and certain health outcomes and highlight the vulnerability of elderly populations to heat despite the prevalence of air conditioning systems. Given the current construction practices and urban warming trends, this vulnerability will continue to grow. Therefore, policies promoting climate adaptive buildings features, as well as better access to reliable and affordable AC are needed. In addition, this research draws attention to the significant potential health consequences of large-scale power outages and proposes the implementation of passive survivability in regulations as one important preventative action. / Dissertation/Thesis / Doctoral Dissertation Engineering 2019

Climate change will most likely increase the frequency of weather extremes in the future. Events such as heat waves may occur more often and proceed for longer time. Heat can have a huge impact on people’s health and higher mortality rates during heat waves are seen all over the world. In Sweden the local municipality has the responsibility for both healthcare of elder and community functions like drinking water. This study aimed to investigate how local Swedish municipalities work proactive against heat waves and if that differs between various geographic parts of the country. A survey was sent out to all local municipalities and got a response rate of 43%, 129 answers of 290. The result showed that nearly 83% of the respondents worked proactive against heat waves in some sort. Actions that they reported was mainly about developing routines and buying air conditions. Focus was to locate these actions in facilities like eldercare and healthcare for vulnerable groups. The proactive work was evenly distributed over the country and no geographic variations could be detected. The most prominent way to prevent health issues during heat waves is to be prepared and work with action plans before the heat occurs. This study indicates that proactive work against heat waves is something that a majority of the local Swedish municipalities work with. That can be seen as positive indication of the preparedness for future heat waves.

No description available.

Climate change will increase the intensity and duration of heat waves in Sweden. Vulnerable communities are especially affected by the effects of heat waves and since children rely on adults to provide comfort, children are particularly affected by heat wave impacts. The aim of this study was to characterize how preschool children and preschool activities were affected by heat exposure based on the perspectives of preschool educators. Six group interviews were conducted with twelve preschool educators in Linköping and Norrköping and the data was analyzed using reflexive thematic analysis. The results indicate that the lack of shaded areas in the preschool yards causes considerable negative impacts on the health of preschool children and obstructs suitable preschool activities. Future research should explore the possibilities of connecting urban planners with preschool educators in the planning phase of preschools in order to utilize their experiences on how to mitigate the effects of heat waves on preschools. / BRIGHT

The growth rings of eastern redcedar (Juniperus virginiana L.) often contain a high frequency of false intra-annual growth bands, which complicates the dendrochronology of this species. However, exactly dated false rings replicated among many trees can reflect major weather changes during the growing season. Sixty-one trees from two sites (Oklahoma and Kansas) were dated and used to compile replicated chronologies of false rings at both locations extending from AD 1700–2000. False-ring events during the modern instrumental era were compared with the daily weather data from nearby stations. Significant false-ring events occurred at both locations during years that experienced a dramatic late-growing season weather reversal, when an extended period of high temperatures and drought was followed by prolonged cool and wet conditions. Synoptic weather maps for these events indicate that all ten replicated false-ring events in the instrumental era occurred during the highly unseasonable penetration of a cold front into the region. However, none of the significant false-ring events occurred in the same year at both sites. These separate false-ring chronologies indicate that there may be phenological differences in the timing of radial growth in redcedar between Kansas and Oklahoma, and that the weather conditions responsible for false-ring formation often occur at the mesoscale and do not often impact central Kansas and northcentral Oklahoma simultaneously.

O objeto desta pesquisa é o desempenho térmico de edifícios residenciais na cidade de São Paulo, tendo em vista as mudanças climáticas previstas e a maior vulnerabilidade da população idosa. O objetivo é a avaliação de desempenho térmico e de conforto ambiental de edifícios residenciais no cenário RCP 8.5 do Quinto Relatório do IPCC - IPCC AR5 e durante a onda de calor ocorrida em janeiro e fevereiro de 2014. Este trabalho se utiliza de estudos de casos reais e de simulações computacionais. O método é indutivo, por meio de levantamentos de campo, e dedutivo, por meio de comparações entre os resultados das medições e das simulações computacionais; o trabalho apresenta, ao final, estudos preditivos do comportamento térmico e do conforto ambiental dos usuários nos edifícios estudados. Para tanto, foram levantadas e monitoradas seis residências de idosos voluntários, além de uma residência de controle, e foram realizadas simulações com o modelo EDSL/Bentley TAS (Thermal Analysis Software). Para a simulação computacional foram utilizados dados climáticos simulados e medidos. Os dados climáticos simulados foram tratados a partir de dados cedidos pelo Instituto de Astronomia, Geofísica e Ciências Atmosféricas/IAG-USP representando os períodos presente (1975 a 2005), futuro próximo (2015 a 2044), futuro intermediário (2045 a 2074) e futuro distante (2076 a 2096). Os dados medidos foram os registrados pela estação meteorológica do IAG-USP, localizada na zona sul de São Paulo, para três períodos distintos: o ano de 2013, quando foram monitoradas as residências, o ano de 1972, selecionado como representativo do período de construção das residências estudadas, e também o ano de 2014, para fins de estudo dos efeitos da onda de calor ocorrida em janeiro e fevereiro desse mesmo ano. Os resultados foram analisados comparativamente entre os diferentes cenários climáticos e também entre as unidades habitacionais estudadas, adotando-se os índices de conforto adaptativo De Dear et al. (1997) / ASHRAE 55 (2013) e Humphreys et al. (2010), considerados os mais adequados para a avaliação térmica da operação em modo passivo no clima local, dentre os índices já existentes. As análises revelaram que, com a progressão dos cenários climáticos futuros, há tendência de alteração na condição de conforto dos usuários com aumento da sensação de calor e redução da sensação de frio, expressos aqui em número de horas e de graus-hora de desconforto. Além disso, sob a ocorrência de ondas de calor, o aumento abrupto e persistente da temperatura do ar tende a tornar as condições de desconforto térmico ainda mais acentuadas. Dentre todos os cenários estudados, e aplicando-se os dois modelos de conforto, foi encontrado um valor médio de aumento da condição de calor de 271%, variando de 83% a 694%, e uma redução média da condição de frio de 51%, variando de 24% a 70%. Os resultados mostram que a conjugação desses dois fenômenos, mudança climática e onda de calor, pode provocar um efeito potencializador para o desconforto térmico por calor, tornando as condições inóspitas para o conforto humano, além de implicar em maior consumo de energia para climatização artificial. / The subject of this research is the residential buildings performance in the city of São Paulo, taking into account the climate changes predicted for the next decades and the greater vulnerability of the elderly related to the environmental conditions. The aim is the evaluation of thermal performance and comfort in residential buildings under the RCP 8.5 scenario from the IPCC Fifth Assessment Report - IPCC AR5, as well as under the heat wave occurred in January and February 2014. This work is based on real case studies and computer simulations. The method is inductive, by field surveys, and deductive, though the comparison between measurements and computer simulation; finally, predictive studies of thermal performance and comfort are presented. For this purpose, six elderly dwellings, besides a control one, were surveyed and monitored, and computer simulations were carried out using EDLS/Bentley TAS (Thermal Analysis Software). For the computer simulations, simulated and measured climate data were employed. The simulated data were treated starting from data provided by the Institute of Astronomy, Geophysics and Atmospheric Sciences/IAG-USP representing the periods present (1975 to2005), near future (2015 to 2044), intermediate future (2045 to 2074 and far future (2076 to 2096). Measured data were recorded by the IAG-USP meteorological station, located in southern São Paulo, for three different periods: 2013, when the residences were monitored; 1972, selected as representative of the buildings\' construction period, and also 2014, to study the January and February heat wave effects. Results were analyzed comparing comfort conditions in the different climate scenarios and also among the case studies, following the adaptive comfort indices De Dear et al. (1997) / ASHRAE 55 (2013) and Humphreys et al. (2010), which were considered the two most appropriate ones, among the existing indexes, for the passive mode operation in the local climate. Analysis revealed a tendency of change in comfort conditions throughout the progression of future climate scenarios, showing an increase in heat sensation and a decrease in cold sensation, which were expressed in number of hours and degree-hours of discomfort. Furthermore, in the occurrence of heat waves, the unexpected and persistent increase in air temperature tends to make thermal discomfort even more pronounced. Among all the studied scenarios, and applying both comfort models, in average, discomfort by heat increased 271%, ranging from 83% to 694%, and discomfort by cold decreased 51%, ranging from 24% to 70%. The results show that the combination of both phenomena, climate change and heat wave, may lead to a potential effect of heat discomfort, making thermal conditions inhospitable for human comfort, besides implying a higher energy consumption for air conditioning.

O objeto desta pesquisa é o desempenho térmico de edifícios residenciais na cidade de São Paulo, tendo em vista as mudanças climáticas previstas e a maior vulnerabilidade da população idosa. O objetivo é a avaliação de desempenho térmico e de conforto ambiental de edifícios residenciais no cenário RCP 8.5 do Quinto Relatório do IPCC - IPCC AR5 e durante a onda de calor ocorrida em janeiro e fevereiro de 2014. Este trabalho se utiliza de estudos de casos reais e de simulações computacionais. O método é indutivo, por meio de levantamentos de campo, e dedutivo, por meio de comparações entre os resultados das medições e das simulações computacionais; o trabalho apresenta, ao final, estudos preditivos do comportamento térmico e do conforto ambiental dos usuários nos edifícios estudados. Para tanto, foram levantadas e monitoradas seis residências de idosos voluntários, além de uma residência de controle, e foram realizadas simulações com o modelo EDSL/Bentley TAS (Thermal Analysis Software). Para a simulação computacional foram utilizados dados climáticos simulados e medidos. Os dados climáticos simulados foram tratados a partir de dados cedidos pelo Instituto de Astronomia, Geofísica e Ciências Atmosféricas/IAG-USP representando os períodos presente (1975 a 2005), futuro próximo (2015 a 2044), futuro intermediário (2045 a 2074) e futuro distante (2076 a 2096). Os dados medidos foram os registrados pela estação meteorológica do IAG-USP, localizada na zona sul de São Paulo, para três períodos distintos: o ano de 2013, quando foram monitoradas as residências, o ano de 1972, selecionado como representativo do período de construção das residências estudadas, e também o ano de 2014, para fins de estudo dos efeitos da onda de calor ocorrida em janeiro e fevereiro desse mesmo ano. Os resultados foram analisados comparativamente entre os diferentes cenários climáticos e também entre as unidades habitacionais estudadas, adotando-se os índices de conforto adaptativo De Dear et al. (1997) / ASHRAE 55 (2013) e Humphreys et al. (2010), considerados os mais adequados para a avaliação térmica da operação em modo passivo no clima local, dentre os índices já existentes. As análises revelaram que, com a progressão dos cenários climáticos futuros, há tendência de alteração na condição de conforto dos usuários com aumento da sensação de calor e redução da sensação de frio, expressos aqui em número de horas e de graus-hora de desconforto. Além disso, sob a ocorrência de ondas de calor, o aumento abrupto e persistente da temperatura do ar tende a tornar as condições de desconforto térmico ainda mais acentuadas. Dentre todos os cenários estudados, e aplicando-se os dois modelos de conforto, foi encontrado um valor médio de aumento da condição de calor de 271%, variando de 83% a 694%, e uma redução média da condição de frio de 51%, variando de 24% a 70%. Os resultados mostram que a conjugação desses dois fenômenos, mudança climática e onda de calor, pode provocar um efeito potencializador para o desconforto térmico por calor, tornando as condições inóspitas para o conforto humano, além de implicar em maior consumo de energia para climatização artificial. / The subject of this research is the residential buildings performance in the city of São Paulo, taking into account the climate changes predicted for the next decades and the greater vulnerability of the elderly related to the environmental conditions. The aim is the evaluation of thermal performance and comfort in residential buildings under the RCP 8.5 scenario from the IPCC Fifth Assessment Report - IPCC AR5, as well as under the heat wave occurred in January and February 2014. This work is based on real case studies and computer simulations. The method is inductive, by field surveys, and deductive, though the comparison between measurements and computer simulation; finally, predictive studies of thermal performance and comfort are presented. For this purpose, six elderly dwellings, besides a control one, were surveyed and monitored, and computer simulations were carried out using EDLS/Bentley TAS (Thermal Analysis Software). For the computer simulations, simulated and measured climate data were employed. The simulated data were treated starting from data provided by the Institute of Astronomy, Geophysics and Atmospheric Sciences/IAG-USP representing the periods present (1975 to2005), near future (2015 to 2044), intermediate future (2045 to 2074 and far future (2076 to 2096). Measured data were recorded by the IAG-USP meteorological station, located in southern São Paulo, for three different periods: 2013, when the residences were monitored; 1972, selected as representative of the buildings\' construction period, and also 2014, to study the January and February heat wave effects. Results were analyzed comparing comfort conditions in the different climate scenarios and also among the case studies, following the adaptive comfort indices De Dear et al. (1997) / ASHRAE 55 (2013) and Humphreys et al. (2010), which were considered the two most appropriate ones, among the existing indexes, for the passive mode operation in the local climate. Analysis revealed a tendency of change in comfort conditions throughout the progression of future climate scenarios, showing an increase in heat sensation and a decrease in cold sensation, which were expressed in number of hours and degree-hours of discomfort. Furthermore, in the occurrence of heat waves, the unexpected and persistent increase in air temperature tends to make thermal discomfort even more pronounced. Among all the studied scenarios, and applying both comfort models, in average, discomfort by heat increased 271%, ranging from 83% to 694%, and discomfort by cold decreased 51%, ranging from 24% to 70%. The results show that the combination of both phenomena, climate change and heat wave, may lead to a potential effect of heat discomfort, making thermal conditions inhospitable for human comfort, besides implying a higher energy consumption for air conditioning.

À Paris environ 44% des bâtiments ont été construits avant 1914 avec des murs épais non isolés et des matériaux poreux, caractérisés par une forte inertie thermique et des propriétés hygroscopiques. Les propriétés hygrothermiques des matériaux utilisés dans les constructions anciennes ont des effets qui : (i) confèrent (aux bâtiments) de bonnes qualités thermiques en période estivale et (ii) contribuent à réguler la température et l’humidité relative intérieure. En France les politiques d’économie d’énergie et la régulation thermique ont abouti à la mise en place de l’isolation thermique afin de réduire les consommations d'énergie pendant l'hiver. L'installation de l'isolation thermique dans la rénovation des bâtiments existants pose cependant des difficultés. D’autre part, il est prévu que des conditions extrêmes de chaleur deviennent plus fréquentes dans des scénarios du climat futur. Ainsi, les évolutions possibles du climat futur doivent être intégrées dans l'évaluation des stratégies de rénovation dans le bâtiment ancien. Ce travail de thèse porte sur l'évaluation du comportement hygrothermique de constructions anciennes rénovées à Paris, dans des conditions météorologiques actuelles et de vague de chaleur. A l’échelle des logements un modèle a été construit sur un outil de simulation thermique dynamique, calé et validé à travers des données enregistrées dans une campagne de mesure lancée en 2014 dans les logements étudiés. À l’échelle de la paroi un modèle macroscopique en 2D est proposé afin d'étudier les transferts de chaleur et de masse dans un mur poreux constitué de plusieurs couches avec de l’isolation thermique par intérieur et par l’extérieur. / In Paris 44% of the dwellings were built before 1914 with uninsulated thick walls made of porous materials, characterized by high thermal inertia and hygroscopic properties. The hygrothermal properties of existing buildings materials have effects that: (i) give (to these buildings) good thermal qualities in summer and (ii) help to regulate indoor temperature and relative humidity. In France the energy saving policies and thermal regulation have resulted in the implementation of thermal regulation to reduce energy consumption during winter. Though the installation of thermal insulation in existing buildings poses a number of difficulties. Moreover, it is expected that extreme heat conditions become more frequent in future climate scenarios. Thus, the possible evolutions of future climate must be integrated into the evaluation of renovation strategies in old buildings. This thesis focuses on the assessment of the hygrothermal behavior of old renovated Parisian buildings, in current and heat wave weather. At the building scale (housing), a model was built in dynamic thermal simulation tool. The model was calibrated and validated through recorded data from a measurement campaign launched in 2014 on the studied housings. At the wall scale, a macroscopic model in 2D is proposed to study the heat and mass transfer through a multilayered porous wall, renovated with internal thermal insulation and external thermal insulation.