Daily variations in TOMS total ozone data

Abstract

The spatial and seasonal distributions of daily fluctuations in total ozone from 60°N to 60°S are analyzed by using 14.5 years of total ozone mapping spectrometer (TOMS) data on a 5° latitude by 15° longitude grid. Root mean square day to day differences maximize near 30 Dobson units (DU) in the midlatitudes of both hemispheres from late fall to early spring. The contributions of these fluctuations due to planetary‐ and medium‐scale waves are analyzed using sinusoidal zonal wave filtering. Daily midlatitude variations from planetary‐scale waves are smaller than those from medium‐scale waves and mainly occur from late fall to early spring, while strong medium‐scale variations persist throughout fall, winter, and spring. An exception is the southern hemisphere high latitudes, where contortions and breakup of the polar vortex cause large daily variations on planetary scales during September and October. Tropical total ozone fluctuations due to planetary‐scale waves are slightly larger than those due to medium‐scale waves in all seasons. A climatological table of monthly RMS day to day total ozone changes is provided as a reference.