  Annular modes explain much of the internal variability of Earth's atmosphere
but have never been identified on other planets. Using reanalyses for Mars and
a simulation for Titan, we demonstrate that annular modes are prominent in the
atmospheres of both worlds, explaining large fractions of their respective
variabilities. One mode describes latitudinal shifts of the jet on Mars, as on
Earth, and vertical shifts of the jet on Titan. Another describes pulses of
midlatitude eddy kinetic energy on all three worlds, albeit with somewhat
different characteristics. We further demonstrate that this latter mode has
predictive power for regional dust activity on Mars, revealing its usefulness
for understanding Martian weather. In addition, our finding of similar annular
variability in dynamically diverse worlds indicates its ubiquity across
planetary atmospheres, opening a new avenue for comparative planetology as well
as an additional consideration for characterization of extrasolar atmospheres.
