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ENSO influence on QBO modulations of the tropical tropopause
journal contribution
posted on 2023-05-19, 12:35 authored by Yuan, W, Geller, MA, Peter LovePeter LoveWe examine the El Niño–Southern Oscillation (ENSO) influence on the quasi-biennial oscillation (QBO) modulation of the cold-point tropopause (CPT) temperatures. An analysis of approximately five decades (in most cases 1950s to near-present) of radiosonde data from 10 near-equatorial stations, distributed along the Equator, shows that the ENSO influence on the QBO is quite zonally symmetric. At all stations analyzed, the QBO has larger amplitude and longer period during La Niña conditions than during El Niño over this total period. We also show that as a consequence of the ENSO influences on QBO periods and amplitudes, the differences between the warmer CPT temperatures during QBO westerly shear conditions and colder temperatures during QBO easterly shear conditions are larger during La Niña than during El Niño for all stations for the entire period considered here. This strengthens earlier findings that the greatest dehydration of air entering the stratosphere from the troposphere occurs during the winter under La Niña and easterly QBO conditions. In addition, stratosphere/troposphere wind and temperature profiles are derived to establish the degree of QBO downward penetration necessary to influence zonal winds and temperatures in the upper troposphere.
History
Publication title
Quarterly Journal of the Royal Meteorological SocietyVolume
140Issue
682Pagination
1670-1676ISSN
0035-9009Department/School
Institute for Marine and Antarctic StudiesPublisher
Royal Meteorological SocPlace of publication
104 Oxford Road, Reading, England, Berks, Rg1 7LjRights statement
Copyright 2013 Royal Meteorological SocietyRepository Status
- Restricted