On the 11 year solar cycle signature in global total ozone dynamics

Abstract

The main aim of the present study is to investigate further the association between total ozone (TOZ) and the 11 year solar cycle (SC) during the period 1979-2010, by employing satellite observations of TOZ made by Nimbus-7, Meteor-3, Earth Probe Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) instrumentation. A statistically significant correlation between the annual mean TOZ over both hemispheres and sunspot number (SN) is found. On the contrary, focusing on the January and February mean monthly TOZ fluctuations from the equator to the high latitudes of the Northern Hemisphere, no association between TOZ and SN is derived. This is attributed to the existence of the quasi-biennial-oscillation (QBO) and the El Niño-Southern oscillation (ENSO) in the TOZ time series. The latter oscillation is herewith expressed by the recently introduced Ozone ENSO Index (OEI). However, when considering the TOZ zonal means centred at 17.5 and 27.5°N during the east phase years of the QBO in the equatorial zonal wind at 50 hPa, a statistically significant correlation between TOZ and SN is revealed. It is an indication that the quasi-periodic fluctuations (i.e. QBO, ENSO) strongly contaminate the relationship between TOZ and solar activity. Plausible mechanisms are discussed, exploring the momentum flux (MF) measurements between 45 and 75°N, in the periods of increased dynamical variability. The findings obtained point to the conclusion that the 11 year solar cycle response in TOZ is caused by dynamical changes which are caused by solar activity. These are of crucial importance because solar radiation is a major driving force of the climate system. © 2012 Royal Meteorological Society.