Teleconnections and the Arctic Oscillation Analyzed in the Barotropic Component of the Model and Observed Atmosphere

[摘要] In this study, teleconnectivity and one point correlations are analyzed for the barotropic component of the atmosphere represented by a simple barotropic model (called barotropic S-model), and the results are compared with a barotropic component calculated from the NCEP/NCAR reanalysis. It is confirmed that the teleconnection of the PNA pattern is simulated reasonably well by the barotropic S-model. The question is focused on whether the Arctic Oscillation (AO) would appear by the one point correlation in the model atmosphere. According to the result, it is found that the one point correlation centered at the Azores High is not restricted within the Atlantic sector like the NAO, but spreads to entire midlatitudes surrounding the Arctic. The positive correlations in the Pacific sector are statistically significant at the 5% confidence level for both the model and observations. From the result, we may suggest that the dynamical AO mode is embedded in the statistical EOF-1 even for the observed atmosphere. The reason for the enhanced correlation in the barotropic component compared with the observed sea level pressure may be that the former is controlled purely by the barotropic dynamics, while the latter is influenced by the baroclinic component of the atmosphere.

[学科分类] 大气科学