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Hauptverfasser: Payez, Alexandre, Stoffelen, Ad, de Valk, Cees, Giesen, Rianne
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2505.08591
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author Payez, Alexandre
Stoffelen, Ad
de Valk, Cees
Giesen, Rianne
author_facet Payez, Alexandre
Stoffelen, Ad
de Valk, Cees
Giesen, Rianne
contents This paper presents a method developed using techniques from extreme value theory to estimate smooth wind-speed percentiles, allowing us to consider more extreme wind speeds while being less sensitive to the noise that stems from the scarcity of extreme data. A reliable characterisation of wind extremes is the first required step for studying decadal trends in tropical-cyclone and extra-tropical-cyclone winds. We develop a percentile-smoothing method using ASCAT-A Level-3 products, focusing on a number of tropical basins (Caribbean and Atlantic), estimate the uncertainty with the block-bootstrap technique to address the issue of dependency, and apply our method to both scatterometer winds (ASCAT-A at two different resolutions) and collocated ERA5 model data. The results obtained are very robust at basin level, without having to rely on a strong assumption for the distribution tail: they are very consistent whether we use exponential fits, generalised-Pareto fits, or even no fit at all, down to at least truly extreme wind percentiles such as 99.999th (main result), and remain quite consistent within uncertainties down to 99.9999th. As ensuring scientifically sound decadal-trend conclusions would require going back sufficiently in time, spanning the lifetimes of different instruments with different characteristics and extreme-wind statistics, a natural follow-on study would be to apply this method not only to ASCAT, but also to its predecessors on QuikSCAT and ERS - comparing each scatterometer individually against ERA5, and also to each other as partial overlaps exist between instruments.
format Preprint
id arxiv_https___arxiv_org_abs_2505_08591
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An extreme value method to study decadal hurricane wind trends
Payez, Alexandre
Stoffelen, Ad
de Valk, Cees
Giesen, Rianne
Atmospheric and Oceanic Physics
This paper presents a method developed using techniques from extreme value theory to estimate smooth wind-speed percentiles, allowing us to consider more extreme wind speeds while being less sensitive to the noise that stems from the scarcity of extreme data. A reliable characterisation of wind extremes is the first required step for studying decadal trends in tropical-cyclone and extra-tropical-cyclone winds. We develop a percentile-smoothing method using ASCAT-A Level-3 products, focusing on a number of tropical basins (Caribbean and Atlantic), estimate the uncertainty with the block-bootstrap technique to address the issue of dependency, and apply our method to both scatterometer winds (ASCAT-A at two different resolutions) and collocated ERA5 model data. The results obtained are very robust at basin level, without having to rely on a strong assumption for the distribution tail: they are very consistent whether we use exponential fits, generalised-Pareto fits, or even no fit at all, down to at least truly extreme wind percentiles such as 99.999th (main result), and remain quite consistent within uncertainties down to 99.9999th. As ensuring scientifically sound decadal-trend conclusions would require going back sufficiently in time, spanning the lifetimes of different instruments with different characteristics and extreme-wind statistics, a natural follow-on study would be to apply this method not only to ASCAT, but also to its predecessors on QuikSCAT and ERS - comparing each scatterometer individually against ERA5, and also to each other as partial overlaps exist between instruments.
title An extreme value method to study decadal hurricane wind trends
topic Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2505.08591