The Upper Atmospheric Research Satellite (UARS) Halogen Occultation Experiment (HALOE) Version 19 ozone profile data set was analyzed for both periodic and nonseasonal polynomial changes in lower stratospheric ozone for 1991--1999. The profile data were screened for cloud contamination at the lowest levels and were then integrated within six half-Umkehr (each ~2.5 km thick) layers from 32 to 253 hPa. The column values were then binned and averaged into 10¿-wide latitude regions but separated into sunrise and sunset measurements, yielding an effective time series of zonal-averaged ozone that spans 8 years. The results extend to near tropopause levels, 253 hPa in the extratropics and 127 hPa in the tropics. Multiple linear regression techniques were applied to the data of each latitude zone and half-Umkehr layer. We developed models that included annual, semiannual, and interannual periodic terms plus polynomial terms at 50 ¿N, 30 ¿N, equator, 30 ¿S, and 50 ¿S. The amplitudes of the three periodic terms vary with latitude and pressure altitude and do not maintain their same order of importance in all cases, emphasizing the changes and hemispheric asymmetry of the transport mechanisms in the lower stratosphere. We find no clear evidence for long-term change at most latitudes and layers. Steady declines in ozone of 0.5% yr-1 were found in the 32--45 hPa layer at 50 ¿S, most likely due to transport of ozone-depleted air from higher latitudes. Our lowest tropical layer (90--127 hPa) shows an ozone decline in the early 1990s but an increase in the last half of the decade. Steady increases of ozone of 3--4% yr-1 were found at 50 ¿N from 127 to 253 hPa and at 30 ¿N from 179 to 253 hPa, probably in response to a changing net circulation for the Northern Hemisphere lower stratosphere. However, there is no highly significant trend at 50 ¿N for the column ozone over the deeper layer from 8 to 253 hPa. For Northern Hemisphere middle latitudes it is concluded that the previously reported declines of zonal-average ozone in the lower stratosphere for the 1980s and early 1990s have not continued over the decade of the 1990s. ¿ 2001 American Geophysical Union