Stratospheric effects of ENSO-related tropospheric circulation anomalies

Abstract

Using 30 years of Northern Hemisphere geopotential data, from 1000 to 10 hPa, the link between three fundamental modes of tropospheric variability [the Pacific/North America (PNA), Western Pacific Oscillation (WPO), and Tropical/Northern Hemisphere (TNH) patterns] and the extratropical wintertime northern stratospheric circulation is explored. These modes of variability are known to be influenced by El Nino/Southern Oscillation (ENSO) and may provide a mechanism for ENSO to influence interannual variability of the stratospheric flow. A comparison is made between the stratospheric influence of the equatorial quasi-biennial oscillation (QBO) and the three tropospheric modes during the December-February period. The effect of the QBO on the stratospheric climate appears to be considerably larger than that from the three tropospheric modes. -from Authors