TIME-VARYING ZONAL ASYMMETRIES IN STRATOSPHERIC N2O AND CH4


H. Gao and J. L. Stanford, Department of Physics and Astronomy, Iowa State University, Ames, IA 50011


Quart. J. Royal Meteor. Soc., London, 119, 591-598 (1992).


Abstract

The purpose of this note is to briefly report results from a search for zonally asymmetric wave 2 perturbations in SAMS (Stratospheric and Mesospheric Sounder) constituent data. SAMS N2O and CH4 constituent data at 7 hPa (approximately 43km altitude) and 45 degrees were analyzed and compared for three Southern winters and early springs (1979-1981). Comparison was also made with stratospheric geopotential height fields were also compared. In the late winter/early spring of each of the three years, eastward moving wave 2 perturbations are found in all of the data fields. The best agreement between eastward phase propagation in the different fields is found when large amplitude waves are present. The continuity equation in middle latitudes is used to show that the time variation of constituent mixing ratio depends on gradients in the mixing ratio as well as geopotential height and temperature fields. Because of the different observed spatial and temporal variations in the mixing ratio for N2O and CH4, it seems reasonable that the two constituents may at times exhibit phase variations.