Explaining the unexplainable: leveraging extremal dependence to characterize the 2021 Pacific Northwest heatwave

Fuente: arXiv
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Main Authors: Zhang, Likun, Risser, Mark D., Wehner, Michael F., O'Brien, Travis A.
Format: Preprint
Published: 2023
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author Zhang, Likun
Risser, Mark D.
Wehner, Michael F.
O'Brien, Travis A.
author_facet Zhang, Likun
Risser, Mark D.
Wehner, Michael F.
O'Brien, Travis A.
contents In late June, 2021, a devastating heatwave affected the US Pacific Northwest and western Canada, breaking numerous all-time temperature records by large margins and directly causing hundreds of fatalities. The observed 2021 daily maximum temperature across much of the U.S. Pacific Northwest exceeded upper bound estimates obtained from single-station temperature records even after accounting for anthropogenic climate change, meaning that the event could not have been predicted under standard univariate extreme value analysis assumptions. In this work, we utilize a flexible spatial extremes model that considers all stations across the Pacific Northwest domain and accounts for the fact that many stations simultaneously experience extreme temperatures. Our analysis incorporates the effects of anthropogenic forcing and natural climate variability in order to better characterize time-varying changes in the distribution of daily temperature extremes. We show that greenhouse gas forcing, drought conditions and large-scale atmospheric modes of variability all have significant impact on summertime maximum temperatures in this region. Our model represents a significant improvement over corresponding single-station analysis, and our posterior medians of the upper bounds are able to anticipate more than 96% of the observed 2021 high station temperatures after properly accounting for extremal dependence.
format Preprint
id arxiv_https___arxiv_org_abs_2307_03688
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Explaining the unexplainable: leveraging extremal dependence to characterize the 2021 Pacific Northwest heatwave
Zhang, Likun
Risser, Mark D.
Wehner, Michael F.
O'Brien, Travis A.
Applications
Methodology
62G32 (Primary), 62D20, 62M30 (Secondary)
In late June, 2021, a devastating heatwave affected the US Pacific Northwest and western Canada, breaking numerous all-time temperature records by large margins and directly causing hundreds of fatalities. The observed 2021 daily maximum temperature across much of the U.S. Pacific Northwest exceeded upper bound estimates obtained from single-station temperature records even after accounting for anthropogenic climate change, meaning that the event could not have been predicted under standard univariate extreme value analysis assumptions. In this work, we utilize a flexible spatial extremes model that considers all stations across the Pacific Northwest domain and accounts for the fact that many stations simultaneously experience extreme temperatures. Our analysis incorporates the effects of anthropogenic forcing and natural climate variability in order to better characterize time-varying changes in the distribution of daily temperature extremes. We show that greenhouse gas forcing, drought conditions and large-scale atmospheric modes of variability all have significant impact on summertime maximum temperatures in this region. Our model represents a significant improvement over corresponding single-station analysis, and our posterior medians of the upper bounds are able to anticipate more than 96% of the observed 2021 high station temperatures after properly accounting for extremal dependence.
title Explaining the unexplainable: leveraging extremal dependence to characterize the 2021 Pacific Northwest heatwave
topic Applications
Methodology
62G32 (Primary), 62D20, 62M30 (Secondary)
url https://arxiv.org/abs/2307.03688