Unexpected Long-Term Variability in Jupiter's Tropospheric Temperatures

TL;DR

This study analyzed 40 years of Jupiter's tropospheric temperatures, revealing unexpected long-term periodicities and hemispheric anti-correlations that challenge existing models and suggest complex dynamical controls.

Contribution

It extends previous observations by uncovering long-term, non-seasonal temperature periodicities and hemispheric anti-correlations over several Jupiter orbits.

Findings

Discovered periodicities of 4, 7, 8-9, and 10-14 years.

Identified anti-correlations between hemispheres at specific latitudes.

Observed equatorial temperature variations are anticorrelated with those higher in the atmosphere.

Abstract

An essential component of planetary climatology is knowledge of the tropospheric temperature field and its variability. Previous studies of Jupiter hinted at periodic behavior that was non-seasonal, as well as dynamical relationships between tropospheric and stratospheric temperatures. However, these observations were made over time frames shorter than Jupiter's orbit or they used sparse sampling. We derived upper-tropospheric (300-mbar) temperatures over 40 years, extending those studies to cover several orbits of Jupiter, revealing unexpected results. Periodicities of 4, 7 8-9 and 10-14 years were discovered that involved different latitude bands and seem disconnected from seasonal changes in solar heating. Anti-correlations of variability in opposite hemispheres were particularly striking at 16, 22 and 30 degrees from the equator. Equatorial temperature variations are also anticorrelated with those 60-70 km above. Such behavior suggests a top-down control of equatorial tropospheric temperatures from stratospheric dynamics. Realistic future global climate models must address the origins of these variations in preparation for their extension to a wider array of gas-giant exoplanets.