40 research outputs found
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
A comparison of three dimensional maximum reach estimation techniques
Spline, periodic spline and spherical harmonic maximum reach estimation procedures are compared and evaluated based on ease of usage, estimation error and bias. The comparison indicates that each method provides comparable estimates based on percent variance accounted for (R2) and standard error. Spherical harmonics, however, are less biased and provide accurate estimates of the maximum reach sphere at the north and south poles, whereas splines and periodic splines are substantially biased in these regions. Three dimensional computer graphic depictions of reach data for the seated operator illustrate these biases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23421/1/0000369.pd
Colleague Crowdsourcing: A Method for Incentivizing National Student Engagement and Large-N Data Collection
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
Leave the Attacking to Others: Assessing the Effectiveness of Candidate Endorsed and Independently Sourced Televised Attack Ads in the 2016 Presidential Election
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