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Climate-driven Arctic coastline modeling: improving erosion forecasts for communities

Investigators

Frank WitmerUniversity of Alaska Anchorage
Matthew KupilikUniversity of Alaska Anchorage

Student

Synopsis

The rapidly warming Arctic is leading to increased rates of coastal erosion, placing hundreds of
Alaska communities at the frontline of climate change. Understanding current rates of coastline
change and accurately forecasting future changes is critical for communities to mitigate and
adapt to these changes. Current modeling approaches typically use a simple linear model based
solely on historical coastline positions to measure rates of change and extrapolate them into the
future. In doing so, these models fail to capture the dynamic effects associated with decreasing
sea ice, increasing annual wave energy, and increasing temperatures. Given the number of
communities threatened by rising rates of erosion, there is a need to expand the scope of these
models and improve their quality.

This proposal has three main objectives:
1. Develop automated processing techniques to incorporate satellite imagery data into
state-of-the-art Arctic coastal erosion models.
2. Generate coastline location forecasts for a selected at-risk Alaska community through
the year 2100 using satellite imagery and downscaled climate data.
3. Engage with stakeholders and communities to co-produce the knowledge, improving the
quality of the models and ensuring that research findings are of direct benefit to them.

Overview

The issue

The rapidly warming Arctic is leading to increased rates of coastal erosion, placing hundreds of
Alaska communities at the frontline of climate change. Understanding current rates of coastline
change and accurately forecasting future changes is critical for communities to mitigate and
adapt to these changes. Current modeling approaches typically use a simple linear model based
solely on historical coastline positions to measure rates of change and extrapolate them into the
future. In doing so, these models fail to capture the dynamic effects associated with decreasing
sea ice, increasing annual wave energy, and increasing temperatures. Given the number of
communities threatened by rising rates of erosion, there is a need to expand the scope of these
models and improve their quality.

Why is this an Alaska Sea Grant project?

The work proposed will directly contribute to the 2018-2021 Alaska Sea Grant Strategic Plan
for Healthy Coastal Ecosystems (Goal 1), Resilient Communities and Economies (especially
Goal 4), and Environmental Literacy and Workforce Development (especially Goal 7). Our
research will contribute to both of the objectives within Goal 1, by co-producing improved
knowledge and forecasts of coastal erosion for communities at risk. These results will also
contribute to the objective of Goal 4 by increasing the capacity of communities and residents to
adapt and respond to environmental changes and coastal hazards. Lastly, we will contribute to
Goal 7 by expanding the Alaska workforce through undergraduate and graduate training.
Undergraduate researchers will be trained in satellite imagery acquisition and processing, and a
graduate student will be trained in coastal erosion models and machine learning techniques.

How will researchers conduct their study?

We will work with stakeholders to select a community to co-produce improved coastal erosion
models. These models will create new historical coastlines from satellite imagery and fieldwork
using Global Navigation Satellite System (GNSS) devices operated in partnership with
community members. These coastlines will be combined with newly downscaled climate data
(e.g. temperature, sea ice, wind) and used as inputs to a nonlinear Gaussian process regression
model. We have implemented a version of this approach on portions of the North Slope of
Alaska and have found considerable improvements in the accuracy of the forecast coastline.