Quantifying the Timescale and Strength of Southern Hemisphere Intraseasonal Stratosphere‐troposphere Coupling

Autor: Elena Saggioro, Theodore G. Shepherd
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Atmospheric Science
Informatics
010504 meteorology & atmospheric sciences
Astrophysics::High Energy Astrophysical Phenomena
Temporal Analysis and Representation
autocorrelation timescale
Time Series Experiments
010502 geochemistry & geophysics
01 natural sciences
Physics::Geophysics
Troposphere
Decadal Ocean Variability
Polar vortex
Oceans
Research Letter
Southern Hemisphere zonal circulation
Global Change
Time Series Analysis
Southern Hemisphere
Stratosphere
Physics::Atmospheric and Oceanic Physics
Stratosphere/Troposphere Interactions
0105 earth and related environmental sciences
Climate Change and Variability
Climatology
Jet (fluid)
zonal circulation trends
Nonlinear Geophysics
Climate Variability
Climate and Interannual Variability
Statistical model
Research Letters
Vortex
Oceanography: General
Geophysics
13. Climate action
Stratosphere‐Troposphere coupling
Atmospheric Processes
General Earth and Planetary Sciences
Environmental science
Satellite
intra‐seasonal transition
Hydrology
Scaling: Spatial and Temporal
Mathematical Geophysics
Time‐series Causal Network
Oceanography: Physical
Zdroj: Geophysical Research Letters
ISSN: 1944-8007
0094-8276
Popis: The Southern Hemisphere zonal circulation manifests a downward influence of the stratosphere on the troposphere from late spring to early summer. However, the strength and timescale of the connection, given the stratospheric state, have not been explicitly quantified. Here, SH zonal wind reanalysis time series are analyzed with a methodology designed to detect the minimal set of statistical predictors of multiple interacting variables via conditional independence tests. Our results confirm from data that the variability of the stratospheric polar vortex is a predictor of the tropospheric eddy‐driven jet between September and January. The vortex variability explains about 40% of monthly mean jet variability at a lead time of 1 month and can entirely account for the observed jet persistence. Our statistical model can quantitatively connect the multidecadal trends observed in the vortex and jet during the satellite era. This shows how short‐term variability can help understand statistical links in long‐term changes.
Key Points Autocorrelation of stratospheric polar vortex variability inflates persistence of cross correlations with the tropospheric eddy‐driven jetA conditional analysis identifies the vortex as statistical predictor for 40% of monthly jet variability in spring/summerThe inferred statistical model explains the enhanced jet persistence and connects the vortex and jet trends observed in the satellite era
Databáze: OpenAIRE
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