ROSSBY-GRAVITY WAVES IN TROPICAL TOTAL OZONE

Randel [1992] has recently reported evidence for Rossby-gravity waves in tropical data fields produced by the European Centre for Medium Ran ge Weather Forecasts (ECMWF). The purpose of this paper is to show tha t similar features axe observable in fields of total column ozone from the Total Ozone Mapping Spectrometer (TOMS) satellite instrument. The observed features are episodic, have zonal (east-west) wavelengths Of approximately 6,000-10,000 km and oscillate with periods of 5-10 days . The modes exhibit westward phase progression and eastward group velo city. A simple linear model is used to estimate the magnitude of total ozone perturbations induced by Rossby-gravity waves. The model is abl e to account for the magnitude of observed TOMS features as well as th eir asymmetry about the equator. The significance of finding Rossby-gr avity waves in total ozone fields is that (1) the report of similar fe atures in ECMWF tropical fields is corroborated with an independent da ta set and (2-) the TOMS data set is demonstrated to possess surprisin g versatility and sensitivity to relatively smaller scale tropical phe nomena.