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Published December 2006 | public
Journal Article

Interaction between eddies and mean flow in Jupiter's atmosphere: Analysis of Cassini imaging data

Abstract

Beebe et al. [Beebe, R.F., et al., 1980. Geophys. Res. Lett. 17, 1–4] and Ingersoll et al. [Ingersoll, A.P., et al., 1981. J. Geophys. Res. 86, 8733–8743] used images from Voyagers 1 and 2 to analyze the interaction between zonal winds and eddies in Jupiter's atmosphere. They reported a high positive correlation between Jupiter's eddy momentum flux, pu'v', and the variation of zonal velocity with latitude, du/dy. This correlation implied a surprisingly high rate of conversion of energy from eddies to zonal flow: ~1.5-3.0 Wm^(-2), a value more than 10% of Jupiter's thermal flux emission. However, Sromovsky et al. [Sromovsky, L.A., et al., 1982. J. Atmos. Sci. 39, 1413–1432] argued that possible biases in the analysis could have caused an artificially high correlation. In addition, significant differences in the derived eddy flux between datasets put into question the robustness of any one result. We return to this long-standing puzzle using images of Jupiter from the Cassini flyby of December 2000. Our method is similar to previous analyses, but utilizes an automatic feature tracker instead of the human eye. The number of velocity vectors used in this analysis is over 200,000, compared to the 14,000 vectors used by Ingersoll et al. We also find a positive correlation between u'v' and du/dy and derive a global average power per unit mass, u'v'du/dy, ranging from (7.1-12.3 x 10^(-5) Wkg^(-1). Utilizing Ingersoll et al.'s estimate of the mass per unit area involved in the transport, this would imply a rate of energy conversion of ~0.7-1.2 Wm^(-2). We discuss the implications of this result and employ several tests to demonstrate its robustness.

Additional Information

© 2006 Elsevier Inc. Received 11 August 2005; revised 21 July 2006. Available online 23 October 2006. We thank our reviewer Larry Sromovsky for his exceedingly thorough and constructive comments. This research was supported by NASA's Planetary Atmospheres Program and by the Cassini Project.

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023