Geometric modelling of spatial extremes

Fuente: arXiv
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Auteurs principaux: Kakampakou, Lydia, Wadsworth, Jennifer L.
Format: Preprint
Publié: 2025
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author Kakampakou, Lydia
Wadsworth, Jennifer L.
author_facet Kakampakou, Lydia
Wadsworth, Jennifer L.
contents Recent developments in extreme value statistics have established the so-called geometric approach as a powerful modelling tool for multivariate extremes. We tailor these methods to the case of spatial modelling and examine their efficacy at inferring extremal dependence and performing extrapolation. The geometric approach is based around a limit set described by a gauge function, which is a key target for inference. We consider a variety of spatially-parameterised gauge functions and perform inference on them by building on the framework of Wadsworth and Campbell (2024), where extreme radii are modelled via a truncated gamma distribution. We also consider spatial modelling of the angular distribution, for which we propose two candidate models. Estimation of extreme event probabilities is possible by combining draws from the radial and angular models respectively. We compare our method with two other established frameworks for spatial extreme value analysis and show that our approach generally allows for unbiased, albeit more uncertain, inference compared to the more classical models. We illustrate the methodology on a space weather dataset of daily geomagnetic field fluctuations.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08192
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Geometric modelling of spatial extremes
Kakampakou, Lydia
Wadsworth, Jennifer L.
Methodology
62H11, 62G32
Recent developments in extreme value statistics have established the so-called geometric approach as a powerful modelling tool for multivariate extremes. We tailor these methods to the case of spatial modelling and examine their efficacy at inferring extremal dependence and performing extrapolation. The geometric approach is based around a limit set described by a gauge function, which is a key target for inference. We consider a variety of spatially-parameterised gauge functions and perform inference on them by building on the framework of Wadsworth and Campbell (2024), where extreme radii are modelled via a truncated gamma distribution. We also consider spatial modelling of the angular distribution, for which we propose two candidate models. Estimation of extreme event probabilities is possible by combining draws from the radial and angular models respectively. We compare our method with two other established frameworks for spatial extreme value analysis and show that our approach generally allows for unbiased, albeit more uncertain, inference compared to the more classical models. We illustrate the methodology on a space weather dataset of daily geomagnetic field fluctuations.
title Geometric modelling of spatial extremes
topic Methodology
62H11, 62G32
url https://arxiv.org/abs/2511.08192