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Activity Number: 39 - Recent Advancements in the Analysis of Extremes
Type: Contributed
Date/Time: Sunday, July 28, 2019 : 2:00 PM to 3:50 PM
Sponsor: Section on Statistics and the Environment
Abstract #305121 Presentation
Title: Trend Analysis of Extreme Coastal Sea Levels from a Semi-Global Tide Gauge Data Set
Author(s): Mintaek Lee* and Jaechoul Lee
Companies: Boise State University and Boise State University
Keywords: Bootstrap confidence interval; Climate change; Genetic algorithm; Generalized extreme value distribution; Temporal correlation

Increase in extreme coastal sea levels can bring disastrous outcomes to people living in coastal regions by increasing flood risks or inducing stronger storm surges. We study trends in monthly maximum sea level by applying extreme value methods. The monthly maximum sea levels are extracted from multiple tide gauges around the coastal regions of the world and as a result naturally contain inhomogeneous changes in their means. Such changes can impact the trend estimates for the sea level data. To rigorously quantify the linear trends in the extreme sea levels, we use a genetic algorithm to detect the time and location of mean shifts induced by changepoints. As strong periodicity and temporal correlation are pertinent to the sea level data, bootstrap techniques are also used to construct more realistic confidence intervals for estimated linear trends and return sea levels. Our preliminary results show that 29 tide gauges (approximately 10% of tide gauges considered) had their estimated linear trends changed by more than 5 cm/decade after considering changepoints. We will summarize our results by presenting maps with estimated linear trends and 50-year return sea levels.

Authors who are presenting talks have a * after their name.

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