Unexpected Long-Term Variability in Jupiter's Tropospheric Temperatures

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.Comment: Primary file: 16 pages, 5 figures. Supplemental File (attached): 12 pages, 3 figures, 1 tabl

Unexpected long-term variability in Jupiter's tropospheric temperatures

International audienceAn essential component of planetary climatology is knowledge of the tropospheric temperature field and its variability. Previous studies of Jupiter hinted at non-seasonal periodic behaviour, as well as the presence of a dynamical relationship between tropospheric and stratospheric temperatures. However, these observations were made over time frames shorter than Jupiter's orbit or they used sparse sampling. Here we derive upper-tropospheric (330-mbar) temperatures over 40 years, covering several orbits of Jupiter. Periodicities of 4, 7-9 and 10-14 years were discovered that involve different latitude bands and seem disconnected from seasonal changes in solar heating. Anticorrelations of variability in opposite hemispheres were particularly striking at 16°, 22° and 30° from the equator. Equatorial temperature variations are also anticorrelated with those observed 60-70 km above. Such behaviour 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

Unexpected long-term variability in Jupiter's tropospheric temperatures

International audienceAn essential component of planetary climatology is knowledge of the tropospheric temperature field and its variability. Previous studies of Jupiter hinted at non-seasonal periodic behaviour, as well as the presence of a dynamical relationship between tropospheric and stratospheric temperatures. However, these observations were made over time frames shorter than Jupiter's orbit or they used sparse sampling. Here we derive upper-tropospheric (330-mbar) temperatures over 40 years, covering several orbits of Jupiter. Periodicities of 4, 7-9 and 10-14 years were discovered that involve different latitude bands and seem disconnected from seasonal changes in solar heating. Anticorrelations of variability in opposite hemispheres were particularly striking at 16°, 22° and 30° from the equator. Equatorial temperature variations are also anticorrelated with those observed 60-70 km above. Such behaviour 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