Analysis of a near-global sea level pressure (SLP) data set for the period 1951-80 was carried out in terms of complex empirical orthogonal function A large-scale, propagating SLP signal was discovered that seems to include variability previously associated with the Southern Oscillation, monsoons and tropical midlatitude teleconnection patterns In this sense, the new feature offers an empirical framework for many of the well-known features of the global climate system. Extensive comparisons show the feature to be observable in the raw data field, and thus not a figment of the analysis technique. The large SLP signal may have its origins in a SLP/snow feedback loop that acts over the region from Siberia to India. It is suggested that the maintenance of the SLP signal involves SLP/precipation feedbacks and, more importantly, the excitation of a major natural mode of climate variation. The SLP signal is only excited at time scales larger than about 18 mouths, i.e., time scales characteristic of ocea... Abstract Analysis of a near-global sea level pressure (SLP) data set for the period 1951-80 was carried out in terms of complex empirical orthogonal function A large-scale, propagating SLP signal was discovered that seems to include variability previously associated with the Southern Oscillation, monsoons and tropical midlatitude teleconnection patterns In this sense, the new feature offers an empirical framework for many of the well-known features of the global climate system. Extensive comparisons show the feature to be observable in the raw data field, and thus not a figment of the analysis technique. The large SLP signal may have its origins in a SLP/snow feedback loop that acts over the region from Siberia to India. It is suggested that the maintenance of the SLP signal involves SLP/precipation feedbacks and, more importantly, the excitation of a major natural mode of climate variation. The SLP signal is only excited at time scales larger than about 18 mouths, i.e., time scales characteristic of ocea...