The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling

Abstract The Pacific/North American (PNA) pattern is a major low‐frequency variability in boreal winter. A recent modeling study suggested that PNA variability increases through extratropical atmosphere‐ocean coupling, but the effect was not fully extracted due to a particular experimental design. B...

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Main Authors: Masato Mori, Hiroki Tokinaga, Yu Kosaka, Hisashi Nakamura, Bunmei Taguchi, Hiroaki Tatebe
Format: Article
Language:English
Published: Wiley 2024-07-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL110234
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author Masato Mori
Hiroki Tokinaga
Yu Kosaka
Hisashi Nakamura
Bunmei Taguchi
Hiroaki Tatebe
author_facet Masato Mori
Hiroki Tokinaga
Yu Kosaka
Hisashi Nakamura
Bunmei Taguchi
Hiroaki Tatebe
author_sort Masato Mori
collection DOAJ
description Abstract The Pacific/North American (PNA) pattern is a major low‐frequency variability in boreal winter. A recent modeling study suggested that PNA variability increases through extratropical atmosphere‐ocean coupling, but the effect was not fully extracted due to a particular experimental design. By comparing coupled and two sets of uncoupled large‐ensemble global model simulations, here we show that the PNA‐induced horseshoe‐shaped sea‐surface temperature (SST) anomaly in the North Pacific returns a non‐negligible influence on the PNA itself. Its magnitude depends on the presence or absence of atmosphere‐ocean coupling. The coupling accounts for ∼16% of the PNA variance, while the horseshoe‐shaped SST anomaly explains only 5% under the uncoupled condition. The coupling reduces the damping of available potential energy by modulating turbulent heat fluxes and precipitation, magnifying the PNA variance. Precipitation processes in the extratropics as well as tropics are therefore important for realistically representing PNA variability and thereby regional weather and climate.
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series Geophysical Research Letters
spelling doaj-art-ba409bb9f3bf4aa89e783c4b21e2421c2025-08-20T02:31:42ZengWileyGeophysical Research Letters0094-82761944-80072024-07-015114n/an/a10.1029/2024GL110234The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean CouplingMasato Mori0Hiroki Tokinaga1Yu Kosaka2Hisashi Nakamura3Bunmei Taguchi4Hiroaki Tatebe5Research Institute for Applied Mechanics Kyushu University Kasuga JapanResearch Institute for Applied Mechanics Kyushu University Kasuga JapanResearch Center for Advanced Science and Technology the University of Tokyo Tokyo JapanResearch Center for Advanced Science and Technology the University of Tokyo Tokyo JapanFaculty of Sustainable Design University of Toyama Toyama JapanJapan Agency for Marine‐Earth Science and Technology Yokohama JapanAbstract The Pacific/North American (PNA) pattern is a major low‐frequency variability in boreal winter. A recent modeling study suggested that PNA variability increases through extratropical atmosphere‐ocean coupling, but the effect was not fully extracted due to a particular experimental design. By comparing coupled and two sets of uncoupled large‐ensemble global model simulations, here we show that the PNA‐induced horseshoe‐shaped sea‐surface temperature (SST) anomaly in the North Pacific returns a non‐negligible influence on the PNA itself. Its magnitude depends on the presence or absence of atmosphere‐ocean coupling. The coupling accounts for ∼16% of the PNA variance, while the horseshoe‐shaped SST anomaly explains only 5% under the uncoupled condition. The coupling reduces the damping of available potential energy by modulating turbulent heat fluxes and precipitation, magnifying the PNA variance. Precipitation processes in the extratropics as well as tropics are therefore important for realistically representing PNA variability and thereby regional weather and climate.https://doi.org/10.1029/2024GL110234PNAteleconnectionatmosphere‐ocean couplingair‐sea couplingair‐sea interaction
spellingShingle Masato Mori
Hiroki Tokinaga
Yu Kosaka
Hisashi Nakamura
Bunmei Taguchi
Hiroaki Tatebe
The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
Geophysical Research Letters
PNA
teleconnection
atmosphere‐ocean coupling
air‐sea coupling
air‐sea interaction
title The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
title_full The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
title_fullStr The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
title_full_unstemmed The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
title_short The Influence of Extratropical Ocean on the PNA Teleconnection: Role of Atmosphere‐Ocean Coupling
title_sort influence of extratropical ocean on the pna teleconnection role of atmosphere ocean coupling
topic PNA
teleconnection
atmosphere‐ocean coupling
air‐sea coupling
air‐sea interaction
url https://doi.org/10.1029/2024GL110234
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