The Vertical Structure of Annular Modes
| Autor: | Daniela I. V. Domeisen, E. A. Lindgren, Aditi Sheshadri, R. Alan Plumb |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
Atmospheric Science 010504 meteorology & atmospheric sciences 13. Climate action Annular mode Stratosphere-troposphere coupling Structure (category theory) Geometry Empirical orthogonal functions 010502 geochemistry & geophysics 01 natural sciences 0105 earth and related environmental sciences |
| Zdroj: | Journal of the Atmospheric Sciences, 75 (10) |
| Popis: | Stratosphere–troposphere interactions are conventionally characterized using the first empirical orthogonal function (EOF) of fields such as zonal-mean zonal wind. Perpetual-winter integrations of an idealized model are used to contrast the vertical structures of EOFs with those of principal oscillation patterns (POPs; the modes of a linearized system governing the evolution of zonal flow anomalies). POP structures are shown to be insensitive to pressure weighting of the time series of interest, a factor that is particularly important for a deep system such as the stratosphere and troposphere. In contrast, EOFs change from being dominated by tropospheric variability with pressure weighting to being dominated by stratospheric variability without it. The analysis reveals separate tropospheric and stratospheric modes in model integrations that are set up to resemble midwinter variability of the troposphere and stratosphere in both hemispheres. Movies illustrating the time evolution of POP structures show the existence of a fast, propagating tropospheric mode in both integrations, and a pulsing stratospheric mode with a tropospheric extension in the Northern Hemisphere–like integration. |
| Databáze: | OpenAIRE |
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