eprintid: 10194544
rev_number: 12
eprint_status: archive
userid: 699
dir: disk0/10/19/45/44
datestamp: 2024-07-16 10:50:28
lastmod: 2024-07-16 10:50:28
status_changed: 2024-07-16 10:50:28
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Ewetola, M
creators_name: Esler, JG
title: The effect of intermittency in wave forcing on the quasi-biennial oscillation
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F59
keywords: Atmospheric flows, internal waves
note: © The Author(s), 2024. Published by Cambridge University Press. This is an Open Access article,
distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/
licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original
article is properly cited.
abstract: The Holton–Lindzen–Plumb (HLP) model of the quasi-biennial oscillation (QBO) is
investigated in order to assess the impact of introducing intermittency in the wave forcing.
Intermittency is introduced to HLP by allowing the amplitude of the waves which force the
QBO to evolve according to a stationary random process, driven by a stochastic differential
equation (SDE) with an associated time scale τ . Provided that τ is much shorter than
the QBO period, it is shown that the impact on the QBO of the intermittent forcing is
captured by a single intermittency parameter λ, and the value of λ is proportional to τ and
otherwise depends upon the details of the SDE. Numerical simulations, using a family of
mean-reverting Ornstein–Uhlenbeck processes as the choice of SDE, show that the effect
of increasing the intermittency parameter is invariably to decrease the QBO amplitude
and increase its period. Changes to the QBO amplitude and period are indeed found to
collapse onto a single curve controlled by λ, as predicted by the theory, provided that τ is
small enough for the approximations used to be valid. The extension to broadband forcing
is discussed in the context of stochastic gravity wave parameterisation, with the eventual
goal of developing a representation of source intermittency in the most general situation
with close fidelity to the physics
date: 2024-06-10
date_type: published
publisher: CAMBRIDGE UNIV PRESS
official_url: https://doi.org/10.1017/jfm.2024.418
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2285243
doi: 10.1017/jfm.2024.418
lyricists_name: Esler, James
lyricists_id: JGESL00
actors_name: Esler, James
actors_id: JGESL00
actors_role: owner
funding_acknowledgements: NE/S00985X/1 [Natural Environment Research Council]
full_text_status: public
publication: Journal of Fluid Mechanics
volume: 988
article_number: A16
pages: 21
issn: 0022-1120
citation:        Ewetola, M;    Esler, JG;      (2024)    The effect of intermittency in wave forcing on the quasi-biennial oscillation.                   Journal of Fluid Mechanics , 988     , Article A16.  10.1017/jfm.2024.418 <https://doi.org/10.1017/jfm.2024.418>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10194544/2/Esler_the-effect-of-intermittency-in-wave-forcing-on-the-quasi-biennial-oscillation.pdf