Spatio-temporal analysis of extreme winter temperatures in Ireland

Fuente: arXiv
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Hauptverfasser: Healy, Dáire, Tawn, Jonathan A., Thorne, Peter, Parnell, Andrew
Format: Preprint
Veröffentlicht: 2024
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author Healy, Dáire
Tawn, Jonathan A.
Thorne, Peter
Parnell, Andrew
author_facet Healy, Dáire
Tawn, Jonathan A.
Thorne, Peter
Parnell, Andrew
contents We analyse extreme daily minimum temperatures in winter months over the island of Ireland from 1950-2022. We model the marginal distributions of extreme winter minima using a generalised Pareto distribution (GPD), capturing temporal and spatial non-stationarities in the parameters of the GPD. We investigate two independent temporal non-stationarities in extreme winter minima. We model the long-term trend in magnitude of extreme winter minima as well as short-term, large fluctuations in magnitude caused by anomalous behaviour of the jet stream. We measure magnitudes of spatial events with a carefully chosen risk function and fit an r-Pareto process to extreme events exceeding a high-risk threshold. Our analysis is based on synoptic data observations courtesy of Met Éireann and the Met Office. We show that the frequency of extreme cold winter events is decreasing over the study period. The magnitude of extreme winter events is also decreasing, indicating that winters are warming, and apparently warming at a faster rate than extreme summer temperatures. We also show that extremely cold winter temperatures are warming at a faster rate than non-extreme winter temperatures. We find that a climate model output previously shown to be informative as a covariate for modelling extremely warm summer temperatures is less effective as a covariate for extremely cold winter temperatures. However, we show that the climate model is useful for informing a non-extreme temperature model.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10796
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spatio-temporal analysis of extreme winter temperatures in Ireland
Healy, Dáire
Tawn, Jonathan A.
Thorne, Peter
Parnell, Andrew
Atmospheric and Oceanic Physics
Methodology
We analyse extreme daily minimum temperatures in winter months over the island of Ireland from 1950-2022. We model the marginal distributions of extreme winter minima using a generalised Pareto distribution (GPD), capturing temporal and spatial non-stationarities in the parameters of the GPD. We investigate two independent temporal non-stationarities in extreme winter minima. We model the long-term trend in magnitude of extreme winter minima as well as short-term, large fluctuations in magnitude caused by anomalous behaviour of the jet stream. We measure magnitudes of spatial events with a carefully chosen risk function and fit an r-Pareto process to extreme events exceeding a high-risk threshold. Our analysis is based on synoptic data observations courtesy of Met Éireann and the Met Office. We show that the frequency of extreme cold winter events is decreasing over the study period. The magnitude of extreme winter events is also decreasing, indicating that winters are warming, and apparently warming at a faster rate than extreme summer temperatures. We also show that extremely cold winter temperatures are warming at a faster rate than non-extreme winter temperatures. We find that a climate model output previously shown to be informative as a covariate for modelling extremely warm summer temperatures is less effective as a covariate for extremely cold winter temperatures. However, we show that the climate model is useful for informing a non-extreme temperature model.
title Spatio-temporal analysis of extreme winter temperatures in Ireland
topic Atmospheric and Oceanic Physics
Methodology
url https://arxiv.org/abs/2412.10796