Spatial Extreme Value Analysis using Point Processes

Examensarbete för masterexamen

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Type: Examensarbete för masterexamen
Title: Spatial Extreme Value Analysis using Point Processes
Authors: Engström, Anne
Abstract: Extreme value theory is a field in statistics dealing with the occurrence of rare events, also known as extreme events. It is commonly found in financial applications, but also when modeling rare environmental events. This Master’s thesis proposes a new methodology for modeling spatio-temporal extreme values, by generalising a method for extremes of a time series to both space and time. The method is applied to data of extreme wildfire activity in the United States, with the goal to predict the risk of wildfires exceeding some large threshold. The model created for predicting extreme wildfires in the spatio-temporal dimension is created from a self-exciting model, with previous events triggering new events. In the spatio-temporal dimension, the self-excitation is dependant on both the time and the distance to previous events, making point processes suitable for modeling these. The resulting model manages to capture both the influence of previous wildfires, as well as the impact of a regions vegetation when assessing the risk of large wildfires in the area. While the model cannot predict the exact locations of all wildfires at a selected time point, it accurately shows the regions with an elevated risk of extensive wildfire activity. It also captures the trend of increasing wildfire activity in the studied area.
Keywords: spatio-temporal extreme value analysis, point processes, peaks over threshold, risk
Issue Date: 2021
Publisher: Chalmers tekniska högskola / Institutionen för matematiska vetenskaper
Collection:Examensarbeten för masterexamen // Master Theses

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