ENSO influence on the variability modes of the boreal winter stratosphere
- Cámara Illescas, Álvaro de la
- García Serrano, Javier
- Ayarzagüena, Blanca
- Ábalos, Marta
- González, Beatriz
- Serrano Cañadas, Enrique
ISSN: 0214-4557
Year of publication: 2009
Issue: 21
Pages: 167-178
Type: Article
More publications in: Física de la tierra
Abstract
The stratospheric circulation has been recently proposed to play an important role in transmitting the ENSO signal to the Euro-Atlantic region. In this context, the influence of ENSO on the boreal stratospheric modes of variability in winter is studied. A Principal Component Analysis of the geopotential height at 20 hPa is performed partitioning the data into El Niño and La Niña winters (1957/58-2001/02 period). It is found that the stratospheric annular mode retains almost a 10% more variance of the field for cold-La Niña than for warm-El Niño winters. On the other hand, zonal-wave-number-one modes accumulate more variability for warm-El Niño winters. Our results support the presence of more stratospheric wave-like anomalies coming from the troposphere during warm-El Niño conditions. Statistical linear correlation between ozone and stratospheric variability is restricted to the annular mode, being the signal stronger for warm- ENSO winters.