Seismology Research at NMSU

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jive_in_nm [2024/08/02 18:50] – jasonjjive_in_nm [2024/08/02 19:09] (current) – [JIVE and Juno] jasonj
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 By tracking the motion of visible clouds in the troposphere we know that the predominant weather pattern in the Jovian atmosphere consists of a series of alternating eastward and westward zonal jets that are remarkably steady over long time scales. We also know that, embedded between these alternating jets, other dynamical structures such as vortices and waves develop. Some of the most prominent of these features, like the Great Red Spot (GRS), are well characterized, and infrared observations indicate that Jupiter has a strong equatorial stratospheric jet.  By tracking the motion of visible clouds in the troposphere we know that the predominant weather pattern in the Jovian atmosphere consists of a series of alternating eastward and westward zonal jets that are remarkably steady over long time scales. We also know that, embedded between these alternating jets, other dynamical structures such as vortices and waves develop. Some of the most prominent of these features, like the Great Red Spot (GRS), are well characterized, and infrared observations indicate that Jupiter has a strong equatorial stratospheric jet. 
  
-[{{:wiki:science:winds.png?direct&400 |Fig. 3. Example intensity image (top panel) whose clouds are tracked to give an estimated velocity map (bottom panel) within a zonal band on Jupiter. JIVE will be able to distinguish wave motion and zonal flows, critical for understanding what powers the jets.  (Click for a larger image) }}]+[{{:wiki:science:vzonalmap.png?direct&400 |Fig. 3. Zonal velocity map from JIVE observations in 2019. The Great Red Spot is apparent. Similar maps of the meridional and vertical motions are also possible to estimate. JIVE will be able to distinguish wave motion and zonal flows, critical for understanding what powers the jets.  (Click for a larger image)  }}] 
  
 Despite the wealth of atmospheric information derived from ground-based observational campaigns and from space missions like Voyager and Galileo, many questions still remain unanswered. The mechanisms maintaing the dominant alternating jets, vortices and waves in the troposphere as well as their structure below the visible cloud level is largely unconstrained by the existing observations. The relationship between small-scale variability in the jets and the observed atmospheric morphology variability is also poorly understood. Finally, it remains unclear the precise role that eddies (large and small) and waves (large and small) play in governing Jupiter's weather pattern and its variability (both in the troposphere and in the stratosphere). Overall, the Jovian weather pattern is a complex system involving many different phenomena at different spatial and temporal scales, and we lack the continuous high-resolution observations of Jupiter's weather system as a whole needed to understand such dynamics. Despite the wealth of atmospheric information derived from ground-based observational campaigns and from space missions like Voyager and Galileo, many questions still remain unanswered. The mechanisms maintaing the dominant alternating jets, vortices and waves in the troposphere as well as their structure below the visible cloud level is largely unconstrained by the existing observations. The relationship between small-scale variability in the jets and the observed atmospheric morphology variability is also poorly understood. Finally, it remains unclear the precise role that eddies (large and small) and waves (large and small) play in governing Jupiter's weather pattern and its variability (both in the troposphere and in the stratosphere). Overall, the Jovian weather pattern is a complex system involving many different phenomena at different spatial and temporal scales, and we lack the continuous high-resolution observations of Jupiter's weather system as a whole needed to understand such dynamics.
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     * a frequency resolution of better than 1 muHz;     * a frequency resolution of better than 1 muHz;
     * accuracy of averaged zonal wind measurements in the Jovian atmosphere of approximately 1-2 m/s;      * accuracy of averaged zonal wind measurements in the Jovian atmosphere of approximately 1-2 m/s; 
 +
 +[{{ :wiki:science:jup_sat_dst.png?direct&300| Example images on the science CCD of Jupiter and Saturn taken with JIVE at the Dunn Solar Telescope in 2021.}}]
  
 No such Jovian ground-based instrument with these capabilities exists, nor does one for current or planned space missions to the giant planets. JIVE is an imaging spectrometer specifically designed to help achieve the scientific goals of this project and to meet these technical specifications. It will measure the Doppler shift in solar absorption lines from light that is reflected by clouds in Jupiter's upper troposphere, providing spatially resolved line-of-sight velocity images of the whole planet at that altitude. More precisely, JIVE is a Fourier transform tachometer that will simultaneously produce a visible image and a Doppler-velocity image of the planet at a regular temporal interval. No such Jovian ground-based instrument with these capabilities exists, nor does one for current or planned space missions to the giant planets. JIVE is an imaging spectrometer specifically designed to help achieve the scientific goals of this project and to meet these technical specifications. It will measure the Doppler shift in solar absorption lines from light that is reflected by clouds in Jupiter's upper troposphere, providing spatially resolved line-of-sight velocity images of the whole planet at that altitude. More precisely, JIVE is a Fourier transform tachometer that will simultaneously produce a visible image and a Doppler-velocity image of the planet at a regular temporal interval.
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 JIVE is operated at the Dunn Solar Telescope at Sacramento Peak in Sunspot, NM.  JIVE is operated at the Dunn Solar Telescope at Sacramento Peak in Sunspot, NM. 
 ==== JIVE and Juno ==== ==== JIVE and Juno ====
-[{{ :wiki:science:rt.png?direct&400|Fig. 4. JIVE and Juno are complementary. The blue box shows the interior range of Jupiter that will be possible to seismically explore with modes detected with JIVE. This includes a deep-interior program (light blue) using low-degree modes, and an envelope program (darker blue) for higher-degree up to l=25 when there is good telescope seeing. The red box shows the near-surface sensitivity possible from gravimetry with the Juno mission. Probe depths of a few example modes at the given frequencies and angular degree are shown (solid lines), as well as the expected transition locations for current Jupiter models (dashed lines). The x-scale is logarithmic. (Click for a larger image) }}]+[{{:wiki:science:rt.png?direct&400 |Fig. 4. JIVE and Juno are complementary. The blue box shows the interior range of Jupiter that will be possible to seismically explore with modes detected with JIVE. This includes a deep-interior program (light blue) using low-degree modes, and an envelope program (darker blue) for higher-degree up to l=25 when there is good telescope seeing. The red box shows the near-surface sensitivity possible from gravimetry with the Juno mission. Probe depths of a few example modes at the given frequencies and angular degree are shown (solid lines), as well as the expected transition locations for current Jupiter models (dashed lines). The x-scale is logarithmic. (Click for a larger image) }}]
  
 JIVE strongly aligns with NASA's Juno mission, whose primary scientific goal is to significantly improve our understanding of the formation, evolution and structure of Jupiter, and arrived at Jupiter in July 2016. Juno will make key contributions with precise measurements of Jupiter's gravity and magnetic fields and will radiometrically sound the deep atmosphere. While these gravitational measurements are primarily sensitive to the outer envelope of the planet, the acoustic waves that JIVE will measure propagate all the way to the core and are thus sensitive throughout the interior. Indeed, as Fig. 4 shows, JIVE is a perfect complement to Juno, and its observational campaigns will overlap with Juno's mission in Jupiter's orbit. Thus it extends Juno's capability, adds to its scientific return, and allows the possibility of critical cross-comparisons of results from two distinct types of measurements. JIVE strongly aligns with NASA's Juno mission, whose primary scientific goal is to significantly improve our understanding of the formation, evolution and structure of Jupiter, and arrived at Jupiter in July 2016. Juno will make key contributions with precise measurements of Jupiter's gravity and magnetic fields and will radiometrically sound the deep atmosphere. While these gravitational measurements are primarily sensitive to the outer envelope of the planet, the acoustic waves that JIVE will measure propagate all the way to the core and are thus sensitive throughout the interior. Indeed, as Fig. 4 shows, JIVE is a perfect complement to Juno, and its observational campaigns will overlap with Juno's mission in Jupiter's orbit. Thus it extends Juno's capability, adds to its scientific return, and allows the possibility of critical cross-comparisons of results from two distinct types of measurements.
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 Regarding seismology of Saturn, recent analysis by Hedman+ of occultation observations using the NASA Cassini spacecraft at Saturn shows exciting evidence of planetary modes that manifest themselves in its rings. This possibility was first proposed by team member Mark Marley and Carolyn Porco. The basic idea is that wave features in Saturn's C rings could be created by resonant interactions with internal oscillation modes, since these modes perturb the internal density profile and, therefore, the external gravity field. The observations of Hedman+ are the indirect evidence of these wave forcings. JIVE will be able to confirm this with direct observations of the global resonant oscillations on the planet. For a description of how the detailed features of these modes might be interpreted, see the excellent work by Jim Fuller.  Regarding seismology of Saturn, recent analysis by Hedman+ of occultation observations using the NASA Cassini spacecraft at Saturn shows exciting evidence of planetary modes that manifest themselves in its rings. This possibility was first proposed by team member Mark Marley and Carolyn Porco. The basic idea is that wave features in Saturn's C rings could be created by resonant interactions with internal oscillation modes, since these modes perturb the internal density profile and, therefore, the external gravity field. The observations of Hedman+ are the indirect evidence of these wave forcings. JIVE will be able to confirm this with direct observations of the global resonant oscillations on the planet. For a description of how the detailed features of these modes might be interpreted, see the excellent work by Jim Fuller. 
  
 +
 +==== Publications to date ====
 +
 +<bibtex furtherreading>
 +citetype=authordate
 +sort=false
 +
 +nocite=2024PSJ.....5..100S
 +nocite=2019Icar..319..795G
 +nocite=2017SPIE10401E..0YU
 +nocite=2012Icar..220..844J
 +
 +
 +</bibtex>
 ==== Meetings ==== ==== Meetings ====
  
jive_in_nm.1722624646.txt.gz · Last modified: 2024/08/02 18:50 by jasonj