Evolution of the equatorial oscillation in Saturn's stratosphere between 2005 and 2010 from Cassini/CIRS limb data analysis

摘要: [1] We present an analysis of thermal infrared spectra acquired in limb viewing geometry by Cassini/CIRS February 2010. We retrieve vertical profiles Saturn's stratospheric temperature from 20 hPa to 10−2 hPa, at 9 latitudes between 20°N and 20°S. Using the gradient wind equation, we derive a map zonal field. Both exhibit oscillation equatorial region. These results are compared maps obtained 2005–2006 CIRS data, when this was first reported. In both epochs, strong anomalies equator (up 20K) consistent with adiabatic heating (cooling) due sinking (rising) motion speed 0.1–0.2 mm/s. Finally, show that altitude maximum eastward has moved downwards 1.3 scale heights 4.2 years, hence ‘phase’ ∼0.5 This rate is estimated period 14.7 years for oscillation, requires local acceleration 1.1 × 10−6 m.s−2 2.5 pressure level. downward propagation it being driven absorption upwardly propagating waves.