12th Conference on Middle Atmosphere

Thursday, 7 November 2002: 2:35 PM
The connection between stratospheric intrusions and tropical convection
Beatriz Funatsu, Johns Hopkins University, Baltimore, MD; and D. Waugh
We examine the relationship between deep convection and stratospheric intrusions into the tropical upper troposphere. Using 20 years of NCEP/NCAR reanalysis data and satellite observations of outgoing longwave radiation (OLR) we examine the climatological structure of potential vorticity (PV) and OLR during intrusion events and during low OLR events. It is shown that transient convection in the central and eastern northern Pacific nearly always occurs together with a tongue of high PV in the upper troposphere, with the low OLR at the leading edge of the PV tongue. This confirms the results of previous studies that have shown a close link between Rossby wave activity and transient convection, and shows that the relevant Rossby waves are of large amplitude and produce tongues of "anomalous" PV. The role that the intrusions play in forcing the convection is examined using PV inversion to determine the vertical motion attributable to the PV tongue.

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