Rossby and Gravity Wave Influences in the Tropical Upper Troposphere and Lower Stratosphere Based on SHADOZ (Southern Hemisphere Additional Ozonesondes) Soundings, 1998-2006

Wave activity in the tropics plays a role in transporting ozone and water vapor in the upper troposphere and lower stratosphere (UT/LS), helping to regulate energy and radiation in this region. The relative importance of advection and convective processes in ozone and water vapor budgets in the tropical UT/LS has been argued through analyses of tracers, related physical parameters (eg OLR, precipitable water, temperature) and with models. Stable laminae in SHADOZ (1998-2006) ozone profiles are interpreted in terms of Rossby wave or gravity wave disturbances with the reasoning that Rossby waves (RW) create ozone filaments transported quasi-horizontally along isentropes; gravity waves (GW) are associated with vertical transport. Using the method of Pierce and Grant [1998] as applied by Thompson et al. [2007], amplitudes and frequencies in ozone laminae are compared among SHADOZ sites in Africa, and over the Pacific, Indian and Atlantic Oceans. Ozone laminae from RW occur more often below the tropical tropopause but with much less frequency than GW that maximizes in the TTL and lower stratosphere. Indices for RW and GW are developed and an exploratory study is carried out to investigate possible causes of these waves.