Colors of Jupiter's large anticyclones and the interaction of a Tropical Red Oval with the Great Red Spot in 2008

Abstract

[1] The nature and mechanisms producing the chromophore agents that provide color to the upper clouds and hazes of the atmospheres of the giant planets are largely unknown. In recent times, the changes in red coloration that have occurred in large-and medium-scale Jovian anticyclones have been particularly interesting. In late June and early July 2008, a particularly color intense tropical red oval interacted with the Great Red Spot (GRS) leading to the destruction of the tropical red oval and cloud dispersion. We present a detailed study of the tropical vortices, usually white but sometimes red, and a characterization of their color spectral signatures and dynamics. From the spectral reflectivity in methane bands we study their vertical cloud structure compared to that of the GRS and BA. Using two spectral indices we found a near correlation between anticyclones cloud top altitudes and red color. We present detailed observations of the interaction of the red oval with the GRS and model simulations of the phenomena that allow us to constrain the relative vertical extent of the vortices. We conclude that the vertical cloud structure, vertical extent, and dynamics of Jovian anticyclones are not the causes of their coloration. We propose that the red chromophore forms when background material (a compound or particles) is entrained by the vortex, transforming into red once inside the vortex due to internal conditions, exposure to ultraviolet radiation, or to the mixing of two chemical compounds that react inside the vortex, confined by a potential vorticity ring barrier.Citation: Sa´nchez-Lavega, A., et al. (2013), Colors of Jupiter's large anticyclones and the interaction of a Tropical Red

Dramatic Change in Jupiter's Great Red Spot From Spacecraft Observations

“…Spectroscopy was performed using Hubble images from 1995 to 2014 to determine the visible-wavelength color of the darkest core of the storm, Figure 1. In this region, the reflectance spectrum (I/F) is fairly constant from 1995 to 2009 (Sanchez-Lavega et al 2013;Simon et al 2014). The greatest change in I/F of up to 0.08 can be seen near 410 nm when comparing data from 1996 and 2008.…”

“…Figure 2 shows enhanced true color and the spectral slope from 631 to 502 nm in 2014, in comparison with similar filters in 2009. There is usually some variation in spectral slope across the GRS, as seen in 2009, but it is generally very muted when compared with a nearby cyclonic barge or small regions in the North Equatorial Belt (NEB), both of which are often redder than the GRS (Sanchez-Lavega et al 2013;Simon et al 2014). In 2014, however, the steepest slope is observed in the GRS core, and the entire GRS collar shows more 500 nm absorption than even dark regions of the NEB.…”

Spectral comparison and stability of red regions on Jupiter

“…The tropospheric haze, which extends from a pressure level to be determined by our analysis down to ~700 mbar, is described by an isotropic phase function (i.e., particles scatter equally in all directions) and the single‐scattering albedo, ϖ 0 [ Sanchez‐Lavega , ; Sanchez‐Lavega et al ., ]. The single‐scattering albedo value ranges between 0, for nonscattering completely absorbing particles, and 1, for nonabsorbing perfect scatterers.…”

“…Sanchez‐Lavega et al . [] compared multiple red anticyclonic region color ratios after normalizing their brightness to the South Tropical Zone. Using this same methodology, the RC has a normalized 410/673 nm ratio of 0.51, slightly lower than that of the GRS and other red regions.…”

“…Other work has focused on the comparison of red and white anticyclones with the GRS, and with generally pale cyclones [e.g., Beebe and Hockey , ; de Pater et al ., , ; Sanchez‐Lavega et al ., ]. However, Jupiter also has a variety of transient, intensely red, cyclonic features, including “barges” in the North and South Equatorial Belts, and the red cyclone (RC), which was visible for brief period in 1994–1995, as seen in Figure .…”