On the role of El Niño - Global Atmospheric Oscillation in the interannual variability of hydrometeorological processes
A review of modern studies of the El Niño - Southern Oscillation (ENSO) teleconnections showed the impact of ENSO on various climatic processes occurring in various parts of the Earth, that is, the global interrelations exerted by ENSO. It is also showed that some climatic processes occurring in various regions of the Earth, which are sometimes quite remote from the tropics of the Pacific Ocean, precede the onset of El Niño or La Niña events and thereby have some apparent effects on ENSO. The recently discovered Global Atmospheric Oscillation (GAO) combines the ENSO itself, as well as forward and reverse teleconnections between the ENSO and the anomalies of surface air temperature and sea level pressure in different regions of the Earth on time scales from 2 to 7 years. GAO is a global mode of interannual climatic variability, and the spatial structure of its anomalies propagates from west to east both in tropics and extratropics.In this work, the amplitudes of fluctuations of global anomalies of the near surface air temperature, sea level pressure, wind speed near the surface, total precipitation and total cloudiness are investigated between the opposite phases of GAO. The global structures of the fields of the oscillation amplitudes of these anomalies and their interconnections with each other are shown. The influence of GAO on the anomalies of the studied atmospheric characteristics in different regions of the Earth is described. Using the Student’s t-test, the probabilities of these anomalies were estimated. A physical mechanism of the manifestation of the transition from the negative to the positive phase of GAO on the beginning of El Niño events is described. Any further development of El Niño and the intensification of its anomalies, in turn, manifest the transition from the positive to negative phase of GAO. Signs of a possible influence of the positive phase of GAO on the enhancement of deep convection in the Greenland Sea, the Labrador Sea and the Weddell Sea were found. However, additional studies are required to confirm the effect of GAO on deep convection in these regions