Further modification of time-longitude lag-correlation diagrams: application to three-dimensional wave propagation

Abstract

The time-longitude lag-correlation analysis of Fraedrich and Lutz is modified to include a second spatial dimension, thereby allowing coherent wave structure to be traced in time in the zonal-height or zonal-meridional planes. This technique is applied to daily hemispheric geopotential height data over 1000-1 mb for Northern and Southern Hemisphere winters. These analyses reveal vertical propagation of Rossby wavetrains from the troposphere into the stratosphere in midlatitudes; the correlation patterns suggest a downstream vertical splitting of the wave trains, with short horizontal scales confined to the troposphere. Zonal-meridional time-lag correlations of time-filtered data reveal the familiar teleconnection and stormtrack patterns seen in previous studies; similarities and differences between hemispheres are discussed.