Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: Michael A. O'Neal, Dept. of Geography. Includes bibliographical references.

Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.

Thesis (M.S.)--University of Toledo, 2008. / Typescript. "Submitted as partial fulfillments of the requirements for The Master of Science in Biology." "A thesis entitled"--at head of title. Bibliography: leaves 35-40.

Climate change has already increased the frequency, intensity, and duration of heat waves around the world. In the coming decades, this trend will continue and likely accelerate, exposing much of the world’s population to historically unprecedented conditions. In some regions, extreme temperatures (as indexed by the annual maximum temperature) are projected to increase at a faster rate than mean daily maximum temperatures. This dissertation shows that under a high emissions scenario, by 2060 – 2080 models project that the most extreme temperatures could warm by 1 – 2°C more than the warm season average in some regions. This amplified warming of the most extreme temperatures is most pronounced in the eastern U.S., Europe, eastern China, and parts of the Amazon rainforest, and may have substantial implications for heat risk in these regions. This dissertation explores the physical mechanisms driving the projected amplified warming of extremes in climate models and assesses the associated uncertainty. It shows that the amplification is linked to reductions in cloud cover, increased net surface shortwave radiation, and general surface drying as represented by declines in the evaporative fraction. In addition to rising temperatures, atmospheric humidity has been observed to increase in recent decades and models project this trend to continue. As a result, joint heat-humidity metrics indicating heat stress are likely to rapidly increase in the future. This dissertation explores how extreme wet bulb temperatures may change throughout the century and assesses the risk of exceeding a fundamental human heat tolerance limit that has been proposed in prior research. It then combines climate data with spatially explicit population projections to estimate the future population exposure to unprecedented wet bulb temperatures. Several regions stand out as being at particular risk: India, the coastal Middle East, and parts of West Africa are likely to experience extremely high wet bulb temperatures in the future, and rapidly growing populations in these regions will result in large increases in exposure to dangerous heat stress. In some areas, it is possible that wet bulb temperatures could occasionally exceed the proposed human tolerance limit by 2080 under a high emissions scenario, but limiting emissions to a moderate trajectory eliminates this risk. Nevertheless, even with emissions reductions, large portions of the world’s population are projected to experience unprecedented heat and humidity in the future. The projected changes in extreme temperatures will have a variety of impacts on infrastructure and other human systems. This dissertation explores how more frequent and severe hot conditions will impact aircraft takeoff performance by reducing air density and limiting the payload capacity of commercial aircraft. It uses performance models constructed for a variety of aircraft types and projected temperatures to assess the payload reductions that may be required in the future. These payload limits, along with sea level rise, changes in storm patterns, increased atmospheric turbulence, and other effects of climate change, stand to have significant economic and operational impacts on the aviation industry. Finally, this dissertation discusses evidence-based adaptation strategies to reduce the impacts of extreme heat in urban areas. It reviews a body of literature showing that effective strategies exist to both lower urban temperatures on a large scale and drastically reduce heat-related mortality during heat waves. Many adaptation techniques are not costly, but have yet to be widely implemented. Given the rapid increases in climate impacts that are projected in the coming decades, it will be essential to rigorously assess the cost-effectiveness of adaptation techniques and implement the most efficient strategies in both high- and low-income areas.

MENVSC (Climatology) / Department of Geography and Geo-Information Sciences / Heat waves are warm extreme temperature events that have environmental and socio-economic impacts in many regions across the world. Negative impacts of warm extreme temperatures over South Africa necessitate the need to study the nature of heat waves. Observations and satellite datasets are analysed in the investigation of the nature and trends of heat waves over South Africa in the present (1983-2012) and future (2010-2039, 2040-2069, 2070-2099) climates. Case study and composite analysis of National Centers for Environmental Prediction datasets were done using the Grids Analysis and Display Systems to get an in-depth understanding of the structure of heat waves in South Africa. Future climate model output obtained from the Conformal Cubic Atmospheric Model was used for future heat wave trends in South Africa. The simulations were made using the Representative Concentration Pathways 4.5 and 8.5. Heat waves are unusual events in the present climate (1983-2012) over much of the country, with 20 of the selected 24 stations experiencing an average of less than one heat wave per season. Heat waves are also more frequent and last longer during warm phase of El Niño-Southern Oscillation (ENSO) than in cool phase of ENSO with the north-east being the most prone region. Composite analysis of 500 hPa omega indicates subsidence over the interior of South Africa in both phases of ENSO. Heat waves in South Africa are localized and associated with a middle level high pressure system that persists over the interior inducing anticyclonic flow and subsidence. The anticyclonic circulation over a region experiencing heat wave weakens with decreasing height over land areas which may be due to frictional forces at the surface and the high is placed further south-east at the surface. Advection of dry continental northerly winds also contributes to high maximum temperatures during heat waves in the interior. Maximum temperatures are expected to increase drastically from the present-day climate to the 2070 – 2099 period, with an average increment of about 8°C during DJF in much of the central interior. As a result, heat wave occurrences are expected to be higher in the future warmer climates when climate change signal is higher. Most increases are expected for heat waves lasting for a week than those lasting for over 2 weeks. CCAM outputs also indicated that heat waves in South Africa are expected to last longer and become more intense during the future warmer climates. Longer lasting and more intense heat waves are expected over the Karoo than in other parts of the country.

Indiana University-Purdue University Indianapolis (IUPUI) / During a 2011 summer dominated by headlines about an earthquake and a hurricane along the East Coast, extreme heat that silently killed scores of Americans largely went unnoticed by the media and public. However, despite a violent spasm of tornadic activity that claimed over 500 lives during the spring of the same year, heat-related mortality annually ranks as the top cause of death incident to weather. Two major data groups used in researching vulnerability to extreme heat events (EHE) include socioeconomic indicators of risk and factors incident to urban living environments. Socioeconomic determinants such as household income levels, age, race, and others can be analyzed in a geographic information system (GIS) when formatted as vector data, while environmental factors such as land surface temperature are often measured via raster data retrieved from satellite sensors. The current research sought to combine the insights of both types of data in a comprehensive examination of heat susceptibility using knowledge-based classification. The use of knowledge classifiers is a non-parametric approach to research involving the creation of decision trees that seek to classify units of analysis by whether they meet specific rules defining the phenomenon being studied. In this extreme heat vulnerability study, data relevant to the deadly July 1995 heat wave in Chicago’s Cook County was incorporated into decision trees for 13 different experimental conditions. Populations vulnerable to heat were identified in five of the 13 conditions, with predominantly low-income African-American communities being particularly at-risk. Implications for the results of this study are given, along with direction for future research in the area of extreme heat event vulnerability.

Indiana University-Purdue University Indianapolis (IUPUI) / In the United States extreme heat events have grown in size and stature over the past 20 years. Urban Heat Islands exacerbate these extreme heat events leaving a sizable portion of people at risk for heat related fatalities. The evidence of this is seen in the Chicago heat wave of 1995 which killed 500 people over the course of a week and the European heat wave of 2003 which killed 7,000 people in the course of a month. The main guiding questions then become how government and the media can most effectively warn people about the occurrence of extreme heat events? Should extreme heat warnings be issued by T.V., newspaper or by radio? Even if warnings are issued will the population at large still change their behavior? Another possible question is whether people most vulnerable to extreme heat will change their behavior? A survey in 2010 by NASA will be the main basis for this analysis. This survey set out to see how well people in Phoenix, Philadelphia, and Dayton responded to extreme heat alerts by changing their behavior.

Indiana University-Purdue University Indianapolis (IUPUI) / Over the past two decades, northern parts of the United States have experienced extreme heat conditions. Some of the notable heat wave impacts have occurred in Chicago in 1995 with over 600 reported deaths and in Philadelphia in 1993 with over 180 reported deaths. The distribution of extreme heat events in Indianapolis has varied since the year 2000. The Urban Heat Island effect has caused the temperatures to rise unusually high during the summer months. Although the number of reported deaths in Indianapolis is smaller when compared to Chicago and Philadelphia, the heat wave in the year 2010 affected primarily the vulnerable population comprised of the elderly and the lower socio-economic groups. Studying the spatial distribution of high temperatures in the vulnerable areas helps determine not only the extent of the heat affected areas, but also to devise strategies and methods to plan, mitigate, and tackle extreme heat. In addition, examining spatial patterns of vulnerability can aid in development of a heat warning system to alert the populations at risk during extreme heat events. This study focuses on the qualitative and quantitative methods used to measure extreme heat events. Land surface temperatures obtained from the Landsat TM images provide useful means by which the spatial distribution of temperatures can be studied in relation to the temporal changes and socioeconomic vulnerability. The percentile method used, helps to determine the vulnerable areas and their extents. The maximum temperatures measured using LST conversion of the original digital number values of the Landsat TM images is reliable in terms of identifying the heat-affected regions.

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study was to locate the most suitable blocks to plant trees within Indianapolis, Indiana’s Near Eastside Community (NESCO). LiDAR data were utilized, with 1.0 meter average post spacing, captured by the Indiana Statewide Imagery and LiDAR Program from March 13, 2011 to April 30, 2012, to conduct a covertype classification and identify blocks that have low canopies, high impervious surfaces and high surface temperatures. Tree plantings in these blocks can help mitigate the effects of the urban heat island effect. Using 2010 U.S. Census demographic data and the principal component analysis, block groups with high social vulnerability were determined, and tree plantings in these locations could help reduce mortality from extreme heat events. This study also determined high and low priority plantable space in order to emphasize plantable spaces with the potential to shade buildings; this can reduce cooling costs and the urban heat island, and it can maximize the potential of each planted tree.