Abstract
Space-time variations of atmospheric ozone in the equatorial middle atmosphere are studied for the 8 year period 1979 to 1986, making use of the ozone mixing ratio data derived from the solar backscatter ultraviolet (SBUV) instrument on board the Nimbus-7. Analysis is made with respect to the long-term variation of the stratospheric zonal mean wind and temperature in the tropics.
From a simple photochemical consideration, it is expected that ozone variations in the upper stratosphere are associated with temperature disturbances having a characteristic time-scale of longer than a few days. Clear evidence is presented for the appearance of equatorially trapped "ozone Kelvin waves" above the 10 mb level having a zonal wavenumber one component and an eastward migration period of about 7 days.
Statistical results for the SBUV ozone data over 8 years shows how Kelvin wave amplitudes are closely related to the semiannual oscillation (SAO) of the zonal mean wind around the stratopause level.
Further discussions are made on the effect of the quasi-biennial oscillation (QBO) of the tropical lower stratosphere on the vertical propagation of fast Kelvin waves, which in turn results in the QBO modulation of the mean field in the upper stratosphere and lower mesosphere.
