Jupiter's Great Red Spot Research Articles

The Thermal Structure and Composition of Jupiter's Great Red Spot From JWST/MIRI

AbstractJupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope (JWST)/Mid‐Infrared Instrument (4.9–27.9 m) in July and August 2022. These observations took place alongside a suite of visual and infrared observations from; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observers which provided both spatial and temporal context across the jovian disc. The stratospheric temperature structure retrieved using the NEMESIS software revealed a series of hot‐spots above the GRS. These could be the consequence of GRS‐induced wave activity. In the troposphere, the temperature structure was used to derive the thermal wind structure of the GRS vortex. These winds were only consistent with the independently determined wind field by JWST/NIRCam at 240 mbar if the altitude of the Hubble‐derived winds were located around 1,200 mbar, considerably deeper than previously assumed. No enhancement in ammonia was found within the GRS but a link between elevated aerosol and phosphine abundances was observed within this region. North‐south asymmetries were observed in the retrieved temperature, ammonia, phosphine and aerosol structure, consistent with the GRS tilting in the north‐south direction. Finally, a small storm was captured north‐west of the GRS that displayed a considerable excess in retrieved phosphine abundance, suggestive of vigorous convection. Despite this, no ammonia ice was detected in this region. The novelty of JWST required us to develop custom‐made software to resolve challenges in calibration of the data. This involved the derivation of the “FLT‐5” wavelength calibration solution that has subsequently been integrated into the standard calibration pipeline.

The Origin of Jupiter's Great Red Spot

AbstractJupiter's Great Red Spot (GRS) is the largest and longest‐lived known vortex of all solar system planets but its lifetime is debated and its formation mechanism remains hidden. G. D. Cassini discovered in 1665 the presence of a dark oval at the GRS latitude, known as the “Permanent Spot” (PS) that was observed until 1713. We show from historical observations of its size evolution and motions that PS is unlikely to correspond to the current GRS, that was first observed in 1831. Numerical simulations rule out that the GRS formed by the merging of vortices or by a superstorm, but most likely formed from a flow disturbance between the two opposed Jovian zonal jets north and south of it. If so, the early GRS should have had a low tangential velocity so that its rotation velocity has increased over time as it has shrunk.

A study of Jupiter's UV Great Dark Spot and tropopause to stratosphere winds in the high northern latitudes as seen by Cassini imaging

Images of Jupiter taken during the year 2000 Cassini flyby revealed the early stages and evolution of a high northern-latitude UV Great Dark Spot over a three-month period. They also provided a window on the circulation of Jupiter's polar stratosphere. Jupiter's rarely-detected UV Great Dark Spot (UVGDS) is unusual in several respects. It is an ephemeral feature, twice appearing as an oval with size and shape similar to Jupiter's Great Red Spot (GRS). Like the GRS, it is an anticyclonic feature. It is unlike the GRS in that: (1) A gas, and/or very small particles (radius < < 1 micro meter, of unknown composition but likely hydrocarbon) is responsible for its contrast with its surroundings; (2) It appears to be a shallow feature, confined to the stratosphere; (3) It evolves (moves in System III longitude, elongates and tilts) over a period of months; and (4) It may be produced by an auroral event as inferred by its proximity to the southern extent of Jupiter's main auroral oval. However, we did not identify a specific auroral trigger event. We measure the rotation rate for the UVGDS to have been ∼20° per Earth day. To investigate the dynamical regime of this feature, we applied an automated cloud feature tracking algorithm to Cassini Imaging Science Subsystem images of Jupiter's northern hemisphere (30°N – 80°N) in the near-IR continuum, methane band, and ultraviolet filters. From these images we were able to derive zonal wind profiles from the middle troposphere cloud tops to the lower stratosphere and track the evolution of the UV Great Dark Spot. Differences in mean zonal wind speed between the continuum and methane band filters indicate a weakening of jets with altitude as far north as 75°N latitude at the altitudes sampled by these filters. We also observe notable differences between the ultraviolet and the other two filters: (1) Winds are significantly weaker and mostly westward in the ultraviolet relative to lower altitudes at all latitudes equatorward of 60°N latitude; (2) Poleward of 60°N latitude, winds observed in the ultraviolet may be faster than those observed in the continuum and methane bands, though we are less confident in this result as Jupiter's haze morphology and the lack of small, discrete, unambiguous trackable features present unique challenges to obtaining reliable mean zonal winds in the ultraviolet at high latitudes.

Temporal Variations in Vertical Cloud Structure of Jupiter's Great Red Spot, Its Surroundings and Oval BA From HST/WFC3 Imaging

AbstractIn this study, we present the evolution of the properties and vertical distribution of the hazes in Jupiter's Great Red Spot (GRS), its surroundings and Oval BA from 2015 to 2021. To retrieve the main atmospheric parameters, we model the spectral reflectivity of a number of dynamically and/or spectrally interesting regions with a radiative transfer tool that uses an optimal estimator scheme. The spectra of the selected regions are obtained from high‐resolution Hubble Space Telescope Wide Field Camera 3 images that cover the spectral range from 200 to 900 nm. The a priori model atmosphere used to describe the various Jovian regions is taken from Anguiano‐Arteaga et al. (2021, https://doi.org/10.1029/2021JE006996) for each corresponding area. We find that the biggest variations in the GRS occur in the optical thickness of the stratospheric and tropospheric haze layers starting in 2019 and in the mean size of the tropospheric haze particles in 2018. The absorption spectra of both hazes show little variations among the analyzed regions and years, with the stratospheric haze properties seeming compatible with the chromophore proposed by Carlson et al. (2016, https://doi.org/10.1016/j.icarus.2016.03.008). We report a color change of Oval BA from red to white during these years that, according to our models, can be mostly explained in terms of a decrease in the stratospheric haze optical depth.

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Baroclinic Model of Jupiter’s Great Red Spot

The paper proposes a quasi-geostrophic baroclinic model of Jupiter’s Great Red Spot as a localized eddy formation in a continuously stratified rotating atmosphere under the action of a horizontal shear flow in the f-plane approximation. On the basis of the theory of ellipsoidal vortices, an analytical relationship is obtained between the geometric dimensions of the vortex, the potential vorticity of the vortex core, and the characteristics of the background flow. Measurements of a number of characteristics of both the vortex and the background current in the Voyager 1 (1979), Galileo (1996), and Cassini (2000) missions were used. Based on the theory, the vertical size of the Jupiter’s Great Red Spot was calculated, which turned out to be close to the same characteristic measured in the Voyager 1 (1979) mission. Based on the theory, an e-stimate of the vertical size of the Great Red Spot of Jupiter was obtained, which is consistent with the e-xperimental data of the Voyager 1 mission (1979).

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging V2

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and Oval BA from HST/WFC3 imaging V2

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and oval BA from HST/WFC3 imaging

Temporal variations in vertical cloud structure of Jupiter's Great Red Spot, its surroundings and oval BA from HST/WFC3 imaging

Vertical Distribution of Aerosols and Hazes Over Jupiter's Great Red Spot and Its Surroundings in 2016 From HST/WFC3 Imaging

AbstractIn this work, we have analyzed images provided by the Hubble Space Telescope's Wide Field Camera 3 (HST/WFC3) in December 2016, with a spectral coverage from the ultraviolet to the near infrared. We have obtained the spectral reflectivity of the GRS and its surroundings, with particular emphasis on selected, dynamically interesting regions. A spectral characterization of the GRS area is performed following two different procedures: (a) in terms of Altitude/Opacity and Color Indices (AOI and CI); (b) by means of automatic spectral classification. We used the NEMESIS radiative transfer suite to retrieve the main atmospheric parameters (e.g., particle vertical and size distributions, refractive indices) that are able to explain the observed spectral reflectivity. The optimal a priori model atmosphere used for the retrievals is obtained from a grid of about 12,000 different atmospheric models, and choosing the one that best fits South Tropical Zone (STrZ) spectra and its observed limb‐darkening. We conclude that the spectral reflectivity of the GRS area is well reproduced with the following layout: (a) a stratospheric haze with its base near the 100 mbar level, with optical depths at 900 nm of the order of unity and particles with a size of 0.3 μm; (b) a more vertically extended tropospheric haze, with τ (900 nm) ∼10 down to 500 mbar and micron sized particles. Both haze layers show a stronger short wavelength absorption, and thus both act as chromophores. The altitude difference between clouds tops in the GRS and surrounding areas is ∼10 km.

Evolution of the Horizontal Winds in Jupiter's Great Red Spot From One Jovian Year of HST/WFC3 Maps

AbstractWe measured the horizontal winds in Jupiter's Great Red Spot (GRS) using data from the WFC3/UVIS instrument on board the Hubble Space Telescope (HST). The data cover 11 epochs from 2009 to 2020. Long‐term monotonic trends in size and shape previously noted from the visible cloud appearance are paralleled by changes in the high‐speed ring around the vortex. The circularization of the GRS cannot be explained by changes in the horizontal wind shear of the surrounding environment. The velocity fields suggest no long‐term trend in the static stability inside or outside the vortex. Instead, the changes are accompanied by a 4%–8% increase in the mean wind speeds of the high‐speed ring from 2009 to 2020. Changes in the wind field coincided with the South Equatorial Belt Outbreak storms of 2016–2017, but not with 2019 "flaking" events involving detachment of red material from the main oval.

Vertical distribution of aerosols and hazes over Jupiter's Great Red Spot and its surroundings in 2016 from HST/WFC3 imaging V2

Vertical distribution of aerosols and hazes over Jupiter's Great Red Spot and its surroundings in 2016 from HST/WFC3 imaging V2

Vertical distribution of aerosols and hazes over Jupiter's Great Red Spot and its surroundings in 2016 from HST/WFC3 imaging

Vertical distribution of aerosols and hazes over Jupiter's Great Red Spot and its surroundings in 2016 from HST/WFC3 imaging

Jupiter's third largest and longest-lived oval: Color changes and dynamics

The transition region between the North Equatorial Band (NEBn) and North Tropical Zone (NTrZ) in Jupiter is home to convective storms, systems of cyclones and anticyclones and atmospheric waves. Zonal winds are weak but have a strong latitudinal shear allowing the formation of cyclones (typically dark) and anticyclones (typically white) that remain close in latitude. A large anticyclone formed in the year 2006 at planetographic latitude 19°N and persists since then after a complex dynamic history, being possibly the third longest-lived oval in the planet after Jupiter's Great Red Spot and oval BA. This anticyclone has experienced close interactions with other ovals, merging with another oval in February 2013; it has also experienced color changes, from white to red (September 2013) and back to white with an external red ring (2015–2016). The oval survived the effects of the closely located North Temperate Belt Disturbance, which occurred in October 2016 and fully covered the oval, rendering it unobservable for a short time. When it became visible again at its expected longitude from its previous longitudinal track, it reappeared as a white large oval keeping this color and the same morphology since 2017 at least until the onset of the new convective disturbance in Jupiter's North Temperate Belt in August 2020. Here we describe the historic evolution of the properties of this oval. We use JunoCam and Hubble Space Telescope (HST) images to measure its size obtaining a mean value of (10,500 ± 1000) x (5,800 ± 600) km2 and its internal rotation finding a value of -(2 ± 1)·10−5 s−1 for its mean relative vorticity. We also used HST and PlanetCam-UPV/EHU multi-wavelength observations to characterize its color changes and Junocam images to unveil its detailed structure. The color and the altitude-opacity indices show that the oval is higher and has redder clouds than its environment but has lower cloud tops than other large ovals like the GRS, and it is less red than the GRS and oval BA. We show that in spite of the dramatic environmental changes suffered by the oval during all these years, its main characteristics are stable in time and therefore must be related with the atmospheric dynamics below the observable cloud decks.

Influences the factors of Cyclones, Anticyclones, Circulation and Rotation to the Steady Dynamic of Great Red Spot of Jupiter

Influences the factors of Cyclones, Anticyclones, Circulation and Rotation to the Steady Dynamic of Great Red Spot of Jupiter

Colour and tropospheric cloud structure of Jupiter from MUSE/VLT: Retrieving a universal chromophore

Recent work by Sromovsky et al. (2017) suggested that all red colour in Jupiter’s atmosphere could be explained by a single colour-carrying compound, a so-called ‘universal chromophore’. We tested this hypothesis on ground-based spectroscopic observations in the visible and near-infrared (480–930 nm) from the VLT/MUSE instrument between 2014 and 2018, retrieving a chromophore absorption spectrum directly from the North Equatorial Belt, and applying it to model spatial variations in colour, tropospheric cloud and haze structure on Jupiter. We found that we could model both the belts and the Great Red Spot of Jupiter using the same chromophore compound, but that this chromophore must exhibit a steeper blue-absorption gradient than the proposed chromophore of Carlson et al. (2016). We retrieved this chromophore to be located no deeper than 0.2±0.1 bars in the Great Red Spot and 0.7±0.1 bars elsewhere on Jupiter. However, we also identified some spectral variability between 510 nm and 540 nm that could not be accounted for by a universal chromophore. In addition, we retrieved a thick, global cloud layer at 1.4±0.3 bars that was relatively spatially invariant in altitude across Jupiter. We found that this cloud layer was best characterised by a real refractive index close to that of ammonia ice in the belts and the Great Red Spot, and poorly characterised by a real refractive index of 1.6 or greater. This may be the result of ammonia cloud at higher altitude obscuring a deeper cloud layer of unknown composition.

Why is the H 3 + hot spot above Jupiter's Great Red Spot so hot?

Recent observations of Jupiter's Great Red Spot indicate that the thermosphere above the storm is hotter than its surroundings by more than 700 K. Possible suggested sources for this heating have thus far included atmospheric gravity waves and lightning-driven acoustic waves. Here, we propose that Joule heating, driven by Great Red Spot vorticity penetrating up into the lower stratosphere and coupling to the thermosphere, may contribute to the large observed temperatures. The strength of Joule heating will depend on the local inclination angle of the magnetic field and thus the observed emissions and inferred temperatures should vary with planetary longitude as the Great Red Spot tracks across the planet.This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H3+, H5+ and beyond’.

The visual spectrum of Jupiter's Great Red Spot accurately modeled with aerosols produced by photolyzed ammonia reacting with acetylene

We report results incorporating the optical properties of the red-tinted photochemically-generated aerosols of Carlson et al. (2016, Icarus 274, 106–115) in spectral models of Jupiter's Great Red Spot (GRS). This material - created in laboratory GRS simulations from acetylene reacting with photolytic products of ammonia produced by ~0.2-μm radiation, similar to solar radiation on Jupiter within and above the upper troposphere, provides an excellent match to 0.35–1.05-μm spectra of the core of the Great Red Spot obtained by the Visual Infrared Mapping Spectrometer (VIMS) during the 2000–2001 Cassini-Huygens flyby. Radiative transfer models of GRS spectra acquired near the central-meridian (CM) and limb by the visual channel of the Cassini/VIMS near closest approach on December 31, 2000 and January 2, 2001, respectively, show remarkable agreement for model morphologies where the following conditions all exist: (1) most of the optical depth of the Carlson et al. (2016) chromophore resides near the top or above the main cloud layer, rather than being uniformly distributed within it, (2) the chromophore consists of relatively small particles in the 0.1–0.2 μm range, and (3) the 1-μm optical depth of the chromophore layer is small, of the order of 0.1–0.2. For such models, the chromophore layer mass abundance is 32–40 μgm cm−2. Consideration of the availability of the acetylene and ammonia parent gas material near the observed chromophore layers gives powerful support for the chromophore residing at the top of the main cloud in the upper troposphere rather than residing as a detached layer in the stratosphere. Under steady-state formation/loss conditions, consideration of plausible eddy diffusion coefficients pertaining to the relatively quiescent Jovian upper atmosphere yield untenable vertical transport times of more than several centuries required to supply the acetylene needed to form the chromophore layer, with stratospheric chromophore models requiring more than half a millennium. Consideration of the convective nature of the GRS and possible presence of acetylene-generating thunderstorms yields upper-troposphere chromophore layer formation times ranging from 11 years to 1.5 months for (1) plausible eddy diffusion coefficients ranging from 104 to 106 cm2 s−1 and (2) efficient conversion of C2H2 and NH3 into the Carlson et al. (2016) chromophore. Thus, the enhanced red coloring of the GRS may be due to the combined effects of (1) the relatively high, 0.2-bar cloudtop where ammonia ice and gas are delivered to prime photo-dissociation altitudes, by (2) powerful convection, which also delivers acetylene from depth created by (3) lightning, which is itself a by-product and indicator of powerful convection, and aided by (4) the vortex nature of the GRS, which helps to confine and concentrate the chromophore as it forms over time within the GRS anticyclone.