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A climatology of rossby and gravity wave influences in the tropical upper troposphere and lower stratosphere based on SHADOZ (Southern Hemisphere Additional Ozonesondes) Soundings, 1998-2006
Amber L. Loucks, Penn State Univ., University Park, PA; and A. M. Thompson, S. Lee, S. K. Miller, D. M. Shelow, and J. C. Witte
Wave activity in the tropics plays a role in transporting ozone and water vapor in the upper troposphere and lower stratosphere (UT/LS), thus 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 (e.g. OLR, precipitable water, temperature) and with models. In this study, stable laminae in SHADOZ (1998-2006) ozone profiles are interpreted in terms of Rossby wave or gravity wave disturbances. The reasoning is that Rossby waves (RW) create ozone filaments transported quasi- horizontally along isentropes and 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 representative SHADOZ sites in Africa, and over the Pacific, Indian and Atlantic Oceans. Ozone laminae from RW occur more often below the tropical tropopause and GW frequency increases 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 the equatorial waves so identified. Preliminary results suggest that the GW signal in the TTL is associated with the Madden-Julian Oscillation.
Session 1, Recent Field Investigations of TTL
Monday, 20 August 2007, 9:00 AM-12:30 PM, Multnomah
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