Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices

Abstract Western disturbances (WDs) are midtropospheric to upper‐tropospheric mesoscale vortices, which typically propagate along the subtropical westerly jet stream and bring heavy rainfall to Pakistan and northern India during boreal winter. They are dynamically similar to Tibetan Plateau vortices...

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Main Authors: K. M. R. Hunt, J. Curio, A. G. Turner, R. Schiemann
Format: Article
Language:English
Published: Wiley 2018-08-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2018GL077734
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author K. M. R. Hunt
J. Curio
A. G. Turner
R. Schiemann
author_facet K. M. R. Hunt
J. Curio
A. G. Turner
R. Schiemann
author_sort K. M. R. Hunt
collection DOAJ
description Abstract Western disturbances (WDs) are midtropospheric to upper‐tropospheric mesoscale vortices, which typically propagate along the subtropical westerly jet stream and bring heavy rainfall to Pakistan and northern India during boreal winter. They are dynamically similar to Tibetan Plateau vortices (TPVs), which affect southwest China during spring and summer and emanate from the Tibetan Plateau. Here we propose that their similarity implies the existence of a more general group of upper‐tropospheric vortices featuring interactions with the orography of the Hindu Kush‐Himalaya‐Tibetan Plateau region. Using existing track databases for WDs and TPVs derived from ERA‐Interim reanalysis, we show that their respective occurrence frequencies are highly anticorrelated with each other through the seasonal cycle, yet both are strongly correlated with jet latitude. Our findings imply that the incidence of hazards due to WDs and TPVs is correlated on intra‐annual and interannual time scales, particularly through upper‐level baroclinicity.
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spelling doaj-art-6fd7e291c9544a5486deb0db87edd6382025-08-20T02:57:52ZengWileyGeophysical Research Letters0094-82761944-80072018-08-0145168629863610.1029/2018GL077734Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau VorticesK. M. R. Hunt0J. Curio1A. G. Turner2R. Schiemann3Department of Meteorology University of Reading Reading UKDepartment of Meteorology University of Reading Reading UKDepartment of Meteorology University of Reading Reading UKDepartment of Meteorology University of Reading Reading UKAbstract Western disturbances (WDs) are midtropospheric to upper‐tropospheric mesoscale vortices, which typically propagate along the subtropical westerly jet stream and bring heavy rainfall to Pakistan and northern India during boreal winter. They are dynamically similar to Tibetan Plateau vortices (TPVs), which affect southwest China during spring and summer and emanate from the Tibetan Plateau. Here we propose that their similarity implies the existence of a more general group of upper‐tropospheric vortices featuring interactions with the orography of the Hindu Kush‐Himalaya‐Tibetan Plateau region. Using existing track databases for WDs and TPVs derived from ERA‐Interim reanalysis, we show that their respective occurrence frequencies are highly anticorrelated with each other through the seasonal cycle, yet both are strongly correlated with jet latitude. Our findings imply that the incidence of hazards due to WDs and TPVs is correlated on intra‐annual and interannual time scales, particularly through upper‐level baroclinicity.https://doi.org/10.1029/2018GL077734western disturbancesTibetan Plateau vorticessubtropicaljetAsiadynamics
spellingShingle K. M. R. Hunt
J. Curio
A. G. Turner
R. Schiemann
Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
Geophysical Research Letters
western disturbances
Tibetan Plateau vortices
subtropical
jet
Asia
dynamics
title Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
title_full Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
title_fullStr Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
title_full_unstemmed Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
title_short Subtropical Westerly Jet Influence on Occurrence of Western Disturbances and Tibetan Plateau Vortices
title_sort subtropical westerly jet influence on occurrence of western disturbances and tibetan plateau vortices
topic western disturbances
Tibetan Plateau vortices
subtropical
jet
Asia
dynamics
url https://doi.org/10.1029/2018GL077734
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AT jcurio subtropicalwesterlyjetinfluenceonoccurrenceofwesterndisturbancesandtibetanplateauvortices
AT agturner subtropicalwesterlyjetinfluenceonoccurrenceofwesterndisturbancesandtibetanplateauvortices
AT rschiemann subtropicalwesterlyjetinfluenceonoccurrenceofwesterndisturbancesandtibetanplateauvortices