Predictability of north Pacific blocking events : Analogue based analysis of historical MIROC6 simulations

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Main Authors: Xavier, Anupama K, Hamilton, Oisín, Faranda, Davide, Vannitsem, Stéphane
Format: Preprint
Published: 2025
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author Xavier, Anupama K
Hamilton, Oisín
Faranda, Davide
Vannitsem, Stéphane
author_facet Xavier, Anupama K
Hamilton, Oisín
Faranda, Davide
Vannitsem, Stéphane
contents Atmospheric blocking exerts a profound influence on mid-latitude circulation, yet its predictability remains elusive due to intrinsic non-linearities and sensitivity to initial-conditions. While blocking dynamics have been extensively studied, the impact of geographical positioning on predictability remains largely unexplored. This study provides a comparative assessment of the predictability of Western and Eastern North Pacific blocking events, leveraging analogue-based diagnostics applied to CMIP6 MIROC6 simulations. Blocking structures are identified using geopotential height gradient reversal, with their temporal evolution analysed through trajectory tracking and error growth metrics. Results reveal that Eastern blocks exhibit lower predictability, characterized by rapid error divergence and heightened mean logarithmic growth rates, whereas Western blocks display dynamical stability. Persistence analysis gives no significant difference between eastern and western North Pacific blocking events. Sensitivity analyses across varying detection thresholds validate the robustness of these findings.
format Preprint
id arxiv_https___arxiv_org_abs_2504_17691
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Predictability of north Pacific blocking events : Analogue based analysis of historical MIROC6 simulations
Xavier, Anupama K
Hamilton, Oisín
Faranda, Davide
Vannitsem, Stéphane
Atmospheric and Oceanic Physics
Atmospheric blocking exerts a profound influence on mid-latitude circulation, yet its predictability remains elusive due to intrinsic non-linearities and sensitivity to initial-conditions. While blocking dynamics have been extensively studied, the impact of geographical positioning on predictability remains largely unexplored. This study provides a comparative assessment of the predictability of Western and Eastern North Pacific blocking events, leveraging analogue-based diagnostics applied to CMIP6 MIROC6 simulations. Blocking structures are identified using geopotential height gradient reversal, with their temporal evolution analysed through trajectory tracking and error growth metrics. Results reveal that Eastern blocks exhibit lower predictability, characterized by rapid error divergence and heightened mean logarithmic growth rates, whereas Western blocks display dynamical stability. Persistence analysis gives no significant difference between eastern and western North Pacific blocking events. Sensitivity analyses across varying detection thresholds validate the robustness of these findings.
title Predictability of north Pacific blocking events : Analogue based analysis of historical MIROC6 simulations
topic Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2504.17691