Subtropical westerly jet influence on occurrence of western disturbances and Tibetan plateau vortices

Hunt, K. M. R. ORCID: https://orcid.org/0000-0003-1480-3755, Curio, J., Turner, A. G. ORCID: https://orcid.org/0000-0002-0642-6876 and Schiemann, R. ORCID: https://orcid.org/0000-0003-3095-9856 (2018) Subtropical westerly jet influence on occurrence of western disturbances and Tibetan plateau vortices. Geophysical Research Letters, 45 (16). pp. 8629-8636. ISSN 0094-8276 doi: 10.1029/2018GL077734

Abstract/Summary

Western disturbances (WDs) are mid-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- and interannual timescales, particularly through upper-level baroclinicity.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/78474
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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