Extended Abstract (1.9M)2.4
Intraseasonal development of a West Pacific pole to pole teleconnection during late austral winter
Keith M. Hines, Byrd Polar Research Center, Ohio State University, Columbus, OH; and D. H. Bromwich
The development on intraseasonal timescales is discussed for an intriguing teleconnection extending from Antarctica to the Arctic during late Austral winter. The teleconnection has previously been found in observations and global climate model simulations. The latter suggest that the teleconnection can be forced from high southern latitudes. The teleconnection pattern includes three primary anomalies in Southern Hemisphere (SH) high latitudes, SH middle latitudes and the Northern Hemisphere subtropics. The teleconnection encompasses the SH high latitude mode/Antarctic Oscillation, and the anticorrelation between the SH subtropical and polar front jet streams. In SH high and middle latitudes, most of the zonally asymmetric component is contrained within zonal wavenumber 1 and connected with changes in the Trans Polar Index. A filtered analysis on intraseasonal timescales confirms the hypothesis that intraseasonal tropical motions (the Madden Julian Oscillation) are closely linked to the teleconnection. An index from the composite of the three primary teleconnection anomalies is correlated to outgoing longwave radiation in the tropical region between 5-20° N and 100-115° E. An analysis helps detail the linkage between the tropical and SH mid-latitude components. Variations, related to the teleconnection, of the subtropical jet stream near Australia are connected with convective inflow and outflow anomalies originating near Indonesia. A more realistic version of the teleconnection appears to be present in National Center for Atmospheric Research (NCAR) Community Climate Model version 3 (CCM3) simulations than in NCAR CCM2 simulations.
Session 2, Large-scale Atmospheric Circulations, Oscillations, and Interactions
Tuesday, 15 May 2001, 8:30 AM-10:00 AM
Previous paper Next paper