Low‐frequency oscillations in total ozone measurements

Low‐frequency oscillations with periods of approximately 1 to 2 months are found in 8 years of global grids of total ozone data from the total ozone mapping spectrometer (TOMS) satellite instrument. The low‐frequency oscillations corroborate earlier analyses based on 4 years of TOMS data. In addition, both annual and seasonal one‐point correlation maps based on the 8‐year TOMS data are presented. The analyses reveal a clear standing “dipole” in ozone perturbations, oscillating with 1‐ to 2‐month periods over the equatorial Indian ocean‐west Pacific region. In a number of instances, large‐scale, exceptionally strong correlations (satisfying a posteriori statistics) are found in the total ozone fields. Very strong correlations occur in the southern midlatitudes at zonal wave one scale. Large‐scale standing patterns are also found in the extratropics of both hemispheres, correlated with ozone fluctuations over the tropical dipole region. In the northern hemisphere, one wave train appears to emanate from the tropical dipole source, extending across the north Pacific and North America and crossing the Atlantic ocean into central Africa. This is interpreted as Rossby wave radiation from the tropical source region.