Temporal variations in spectral reflectivity and vertical cloud structure of Jupiter’s Great Red Spot and its surroundings

Jupiter's Great Red Spot (GRS) is a remarkable phenomenon among solar system atmospheres. In addition to its unique dynamical properties, the vertical structure of its clouds and hazes is a relevant subject of study, being of particular interest the unknown chromophore species responsible for the GRS characteristic reddish color. In a recently published paper (Anguiano-Arteaga et al., 2021) we showed the existence of a stratospheric haze (P < 100 mbar) that seemed to be compatible with the chromophore-candidate proposed by Carlson et al. (2016), although a second coloring agent located in the upper tropospheric levels (P < 500 mbar) was also suggested.

In this study, we have analyzed high-resolution images obtained with the Hubble Space Telescope’s Wide Field Camera 3 between 2015 and 2021, with a spectral coverage from the UV to the near IR, including two methane absorption bands. Following the same procedure as in our previous paper, we have obtained the spectral reflectivity of the GRS and a few dynamically interesting regions in the surrounding area under different viewing geometries.

From the measured spectra, and following the scheme proposed by Anguiano-Arteaga et al. (2021), we retrieved several key atmospheric parameters (optical depths, particle vertical and size distributions and refractive indices) for each of the regions using the NEMESIS radiative transfer suite (Irwin et al., 2008). We show the spatial and temporal variations on these parameters, including the evolution of the properties of the chromophore species.

References

- Anguiano-Arteaga, A., Pérez-Hoyos, S., Sánchez-Lavega, A., Sanz-Requena, J. F., & Irwin, P. G. J. (2021). Vertical distribution of aerosols and hazes over Jupiter's Great Red Spot and its surroundings in 2016 from HST/WFC3 imaging. J. Geophys. Res. Planets., 126, e2021JE006996 https://doi.org/10.1029/2021JE006996

- Carlson, R.W., Baines, K.H., Anderson, M.S., Filacchione, G., & Simon, A.A. (2016). Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiter’s Great Red Spot. Icarus, 274, 106-115. https://doi.org/10.1016/j.icarus.2016.03.008

- Irwin, P.G.J., Teanby, N.A., de Kok, R., Fletcher, L.N., Howett, C.J.A., Tsang, C.C.C., Wilson, C.F., Calcutt, S.B., Nixon, C.A., & Parrish, P. D. (2008). The NEMESIS planetary atmosphere radiative transfer and retrieval tool. J. of Quant. Spec. and Radiative Transfer, 109 , 1136-1150. https://doi.org/10.1016/j.jqsrt.2007.11.006