The Relationship between the Meridional Profile of Zonal-mean Geostrophic Wind and Station Wave at 500 hPa

The sea-level pressure (SLP), 500 hPa height, zonal-mean 500 hPa height ([Z₅₀₀]), stationary wave eddy component of the 500 hPa height (Z*₅₀₀) and zonal-mean 500 hPa geostrophic wind [U_g] fields poleward of 20°N are examined for the period 1958-1997, with emphasis on the winter season. The relationships between the Arctic Oscillation (AO)index and algebraic difference of the zonal-mean wind in 55°N and 35°N (Ut) index were investigated, making use the Monte Carlo procedure, Singular Value Decomposition (SVD), Empirical orthogonal function (EOF) and regression method. The leading modes of empirical orthogonal function (EOF's) of SLP are more robust than the 500 hPa height EOF's, not only in the ratio of the two largest eigenvalues, but in more zonally symmetric. Comparing the meridional profiles of zonal-mean wind amplitude associated with the AO and Ut index, the profiles for the two indexes are very similar, both with respect to amplitude and the placement of the maximum and minimum. Comparing the station wave component of 500 hPa height field regressed upon the AO and Ut index, there is one-to-one correspondence between all the major centers of action in the two maps, especially in the North Atlantic and Eurasian continent. The pattern is unlike the prominent teleconnection patterns, they have hemispheric extent and cannot be interpreted in term of the individual wavetrains.