Influence of El Niño on parameters of the middle and upper atmosphere over Eastern Siberia according to reanalysis and model data in winter

Abstract

One of the most important climate-forming phenomena in the ocean—atmosphere system is the El Niño Southern Oscillation (ENSO) events, which manifest themselves with varying intensity in almost all regions of the globe. The central regions of Eurasia are farthest from the tropics of the Pacific Ocean, the regions where ENSO originates. There are different points of view regarding the nature of the ENSO effect on these regions. In the presented work, the influence of ENSO on the upper atmosphere of the Northern Hemisphere and, in particular, on the upper atmosphere of Eastern Siberia is estimated using model calculations and reanalysis data. The results of the analysis show that the large-scale structures of the atmospheric response to the ENSO events in the Northern Hemisphere are similar according to modeling and reanalysis, yet the regions of Eastern Siberia are on the periphery of the main signal and there are significant differences in estimated effects from one case of El Niño and La Niña to another. In January, ENSO has the greatest impact on the middle atmosphere of the polar regions of the Northern Hemisphere. Over Eurasia and Eastern Siberia, the atmospheric response to the ENSO events turned out to be weak or absent.