The mean state of the global atmospheric energy cycle is re‐examined using the two reanalysis datasets — NCEP2 and ERA40 (1979–2001). The general consistency between the two datasets suggests that the present estimates of the energy cycle are probably the most reliable ones. The comparison between the present and a previous study shows noticeable discrepancies in some of the energy components and conversion rates. The current estimate of the transformations from mean potential energy to mean kinetic energy C(PM, KM) further suggests that the near‐surface processes play an important role in the conversion rate C(PM, KM), along with the Ferrel cell and Hadley cells, which probably change the direction of the conversion rate C(PM, KM).

No abstract

Observations of planets throughout our Solar System have revealed that the Earth is not alone in possessing natural, inter-annual atmospheric cycles [1-4]. The equatorial middle atmospheres of the Earth, Jupiter and Saturn all exhibit a remarkably similar phenomenon -a vertical, cyclic pattern of alternating temperatures and zonal (east-west) wind regimes that propagate slowly downwards with a well-defined multi-Earth-year period. Earth's Quasi-Biennial Oscillation (QBO, observed in the lower stratospheres with an average period of 28 months) is one of the most regular, repeatable cycles exhibited by our climate system [1], and yet recent work has shown that this regularity can be disrupted by events occurring far away from the equatorial region [5,6], an example of a phenomenon known as atmospheric teleconnection. Here we reveal that Saturn's equatorial Quasi-Periodic Oscillation (QPO, with a ~15-year period) can also be dramatically perturbed. An intense springtime storm erupted at Saturn's northern mid-latitudes in December 2010 [7,8,9], spawning a gigantic hot vortex in the stratosphere at 40 o N that persisted for 3 years [10]. Far from the storm, the Cassini temperature measurements showed a dramatic ~10-K cooling in the 0.5-5 mbar range across the entire equatorial region, disrupting the regular QPO pattern and significantly altering the middle-atmospheric wind structure, suggesting an injection of westward momentum into the equatorial wind system from waves generated by the northern storm. Hence, as on Earth, meteorological activity at mid-latitudes can have a profound effect on the regular atmospheric cycles in the tropics, demonstrating that waves can provide horizontal teleconnections between the phenomena shaping the middle atmospheres of giant planets. Author ContributionsLNF was responsible for analysing the nadir data and writing the article. SG and TF analysed Cassini limb observations and assisted with the nadir-limb comparison and calculation of zonal winds. LL provided a cross-comparison of zonal winds via a different algorithm, and MF provided assistance with the wind calculations. GSO assisted with the ground-based observing campaign. PGJI developed the software to permit inversions of Cassini/CIRS spectra. NG generated the CIRS spectral database. All authors read and commented on the manuscript.

No abstract

The radiant energy budget and internal heat are fundamental properties of giant planets, but precise determination of these properties remains a challenge. Here, we report measurements of Jupiter’s radiant energy budget and internal heat based on Cassini multi-instrument observations. Our findings reveal that Jupiter’s Bond albedo and internal heat, 0.503 ± 0.012 and 7.485 ± 0.160 W m−2 respectively, are significantly larger than 0.343 ± 0.032 and 5.444 ± 0.425 Wm−2, the previous best estimates. The new results help constrain and improve the current evolutionary theories and models for Jupiter. Furthermore, the significant wavelength dependency of Jupiter’s albedo implies that the radiant energy budgets and internal heat of the other giant planets in our solar system should be re-examined. Finally, the data sets of Jupiter’s characteristics of reflective solar spectral irradiance provide an observational basis for the models of giant exoplanets.