ENSO as a Sequence to the Global Atmospheric Oscillation

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Wednesday, 5 February 2014
Hall C3 (The Georgia World Congress Center )
Vladimir I. Byshev, Russian Academy of Sciences, Moscow, Russia; and V. G. Neiman, Y. A. Romanov, and I. V. Serykh

When searching for potential precursors of the El Niño – Southern Oscillation (ENSO) phenomenon in the Pacific, it was found that a large-scale negative SST anomaly appears in Northern Indian Ocean prior to the occurrence of El Niño event in Pacific basin. This anomaly is accompanied by growth of atmospheric pressure which gradually extends eastwards along the equator then overlapping the zone of planetary convection within the Indonesian Region. The west wind that emerges on the eastern periphery of the mentioned anomaly leads to reversal of the Pacific segment of the Walker equatorial atmospheric circulation and to a subsequent change in the zonal thermal dipole polarity in the tropical zone of the Pacific (the latter means culmination of the ENSO phenomenon). In addition to the mentioned thermo-baric anomaly in the Indian Ocean, other obvious signs of large-scale pressure anomalies have been found in the Global atmospheric pressure field. The parameters describing the spatial structure of the anomalies in the planetary fields of the principal hydrometeorological characteristics, formed prior the beginning and during the main phase of the ENSO phenomenon in the Pacific Ocean, indicate that these quasi-synchronous disturbances of the general environment observed in different regions are caused by the planetary process revealing in the form of interannual variations of the climatic system dynamics. These anomalies were considered as manifestation of the interannual Global oscillation in the dynamics of the modern climatic system. The process, referred to as “Global Atmospheric Oscillation” (GAO) in the present work, is manifested in such a way that once every 3.5 years, on average, the climatic system of the Earth undergoes a certain shift, the consequences of which affect more or less quasi-synchronously all the characteristics of the system. Thus, we can assume that the peculiarities in the fields of hydrophysical characteristics of the ocean and meteorological characteristics of the atmosphere discussed above resulted directly from the GAO effect. Attached Fig., which was drafted on background of above mentioned calculations, presents the baric appearence of GAO. Due to the presence of feed-forwards and feedbacks in the climatic system dynamics, the large-scale anomalies of characteristics appearing as the result of GAO process development have their back or secondary effect on the system of interaction of the ocean-atmosphere-land. This is the secondary effect of the discussed phenomenon, which can be implemented either by direct exchange of properties between the adjacent media (this is seen most explicitly in the Pacific Region), or owing to distant teleconnections between the concrete climatic subsystems in different parts of the Planet. It is apparently that the secondary, or indirect, GAO impact spreading through the system of general atmospheric circulation has a certain phase delay, which likely depends on the climatic peculiarities of the “recipient” regions and their distance from the respective climatic anomalies, in particular, from the most intensive of them, appearing in the equatorial zone of the Pacific. Therefore it is suggested that the whole known complex of events related to the ENSO phenomenon in the Pacific is a consequence and a regional link of the planetary structure of this global atmospheric phenomenon. Therewith it should be noted that climatic system of the Indian Ocean domain is obviously subjected to the ENSO impact in full measure, which appears to be considered as the general effect of GAO. On the other hand, there are some evidences that Madden-Julian Oscillation as an element of GAO triggers the Kelvin wave that has direct effect on the set of El Niño events.