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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Wildfire as Coupled Human Natural System

Farkhondehmaal, Farshad 01 February 2022 (has links)
Wildfire activity has increased in recent years in the United States, endangering both environment and society. Appropriate management of this phenomenon is only achievable with a thorough understanding of the critical factors influencing wildfire activity in each region. In three essays, I use statistical and mathematical models to examine wildfires and propose solutions to mitigate their impact on society. In the first essay, I focused on building a systematic framework for modeling wildfire as a coupled human-natural system. I employ system dynamics modeling, which was previously applied in various fields, including healthcare, sustainability, and disaster mitigation. I show how, in the absence of exogenous factors such as temperature or lightning, the human perception of fire danger may establish a feedback loop that can yield significant trends such as fluctuation or even fluctuation with rising amplitude when linked with the natural system. This conclusion is counter-intuitive, given that the human contribution to wildfire is typically described in the literature using constant or semi-constant variables. Additionally, I analyzed the impact of three important fire protection measures on reducing burning rates (prescribed burning, enhancing immediate suppression accomplishment, and regulating the rate of WUI growth). The research concludes that appropriately integrating several policies can result in a synergistic effect that is greater than the sum of the effects of the individual policies. The second essay calibrates the model built in the first essay and examines wildfire trends across the contiguous United States. The simulation results closely match the real data, and the model serves as a foundation for data-driven policy research. To be more precise, I fit the model to each state separately and then compare the model's goodness of fit. Following that, I examine the influence of various policies and scenarios on wildfire behavior. In the scenario, I examine the effect of maintaining constant temperatures and precipitation levels relative to the average values for these variables over the last century. For the policy analysis, I examine the influence of three policies on each state (prescribed burning, increasing immediate suppression achievement, and regulating the rate of WUI development). Here, I provide state-specific suggestions about the primary factors that contribute to wildfires and the most effective policies for each state. In the third essay, I have implemented the Oregon wildfire history dataset and integrated it with two other aerial datasets, including meteorological data gathered by weather stations located around the state and counties. Then, using hierarchical modeling on over 10,000 wildfire ignitions, I developed a classification system for determining if a given fire has the potential to grow major or not. However, utilizing a huge dataset and a variety of resources presents several obstacles, such as the presence of missing data. I imputed the missing numbers using a sophisticated mathematical approach called "Predictive Mean Matching". / Doctor of Philosophy / Wildfire activity has increased in recent decades in the United States, which put many people in danger. Climate change, the Settlement of people in the Wildland Urban Interface, and an increase in vegetation density each play a role in this increase. In this dissertation, we discuss the wildfire in the United States in three essays. In the first essay, we develop a mathematical model to show how humans and nature affect wildfire activity in any area. We then test different major wildfire management policies on the hypothetical situation to compare the outcome of these policies together. In the second essay, we use the model developed in the essay (with some minor changes) to model the wildfire activity in 11 states of the U.S. which has the most wildfire activity in recent years. First, we show that our model can replicate the wildfire activity in each state. Second, we test the effect of wildfire mitigation policies on each state. This essay proposes state-specific policy recommendations based on the main reasons for the increase in wildfire activity in each state. Finally, in the third essay, we develop a statistical model to predict the existence of large wildfires in the next month in Oregon counties. We use climate, land, and fire history data to develop a warning system. Policymakers can use this system to move the fire suppression resources to counties with a high probability of experiencing large wildfires over the next month. Finally, all essays aim to enhance our understanding of the reasons for the increase in wildfire activity in recent years and suggest finding the appropriate way to deal with this change to reduce the effect of wildfire on human life.

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