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L. A. Young (SwRI)
Breaking gravity waves are expected to be important in the energy and momentum budgets of the stratospheres of Titan and the jovian planets (e.g., French and Gierasch 1974, JAS 31, 1701; Roques et al. 1994, A&A 288, 985; Young et al. 2001, Icarus, in press), based on temperature fluctuations seen in profiles derived from stellar occultations or the Galileo ASI. Fourier analyses (Cooray et al. 1998, Icarus 132, 298; Sicardy et al. 1999, Icarus 142, 357, Young et al. 2001, in prep) show that these fluctuations have the same power-law dependence on vertical wavenumber as those observed in the Earth's atmosphere (Allen & Vincent 1995, JGR 100, 1327) or predicted theoretically (Smith et al. 1987, JAS 44, 1404; Hines 1991, JAS 48, 1360), supporting the gravity-wave interpretation. However, Fourier analysis is poor at describing local behavior. For this reason, wavelets (localized in both space and wavenumber) are often used to study turbulence and gravity waves (e.g., Sato and Yamada 1994, JGR 99, 20623; Yamada & Ohkitani 1991, Prog. Theor. Phys. 86, 799; Farge et al. 2001, Phys. Rev. Lett. 87, 054501). Wavelet decomposition of stellar occultation data can be accompished by first describing the refractivity as a product of an exponential and a sum of wavelet purturbations, and then generating model lightcurves. Furthermore, a wavelet decomposition approach to modeling stellar occultations maintains the flexibility of inversion techniques (by not assuming an a priori functional form), and the rigor of forward modeling (by including effects such as finite star size and wave optics).
This work was supported in part by grants from NASA's PG&G and Planetary Atmospheres programs.
The author(s) of this abstract have provided an email address for comments about the abstract: layoung@boulder.swri.edu