Universität zu Köln

Dott, A.‐C. ORCID: 0009-0002-8605-639X, Saur, J. ORCID: 0000-0003-1413-1231, Schlegel, S. ORCID: 0000-0002-4779-2813, Strobel, D. F. ORCID: 0000-0002-0944-8675, de Kleer, K. ORCID: 0000-0002-9068-3428 and de Pater, I. ORCID: 0000-0002-4278-3168 (2025). Observed Latitudinal, Longitudinal and Temporal Variability of Io's Atmosphere Simulated by a Purely Sublimation Driven Atmosphere. Journal of Geophysical Research: Planets, 130 (7). pp. 1-25. Wiley. ISSN 2169-9097

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Abstract

[Artikel-Nr.: e2024JE008869] How much of Io's SO2 atmosphere is driven by volcanic outgassing or sublimation of SO2 surface frost is a question with a considerable history. We develop a time dependent surface temperature model including thermal inertia and the exact celestial geometry to model the radiation driven global structure and temporal evolution of Io's atmosphere. We show that many observations can be explained by assuming a purely sublimation driven atmosphere. We find that a thermal diffusivity α = 2.41 × 10 7 m2s 1 yields an averaged atmospheric SO2 column density decreasing by more than one order of magnitude from the equator to the poles in accordance with the observed spatial variations of Io's column densities. Our model produces a strong day‐ night‐asymmetry with modeled column density variations of almost two orders of magnitude at the equator as well as a sub‐anti‐Jovian hemisphere asymmetry, with maximum dayside column densities of 3.7 × 1016 cm 2 for the sub‐Jovian and 8.5 × 1016 cm 2 for the anti‐Jovian hemisphere. Both are consistent with the observed temporal and large‐scale longitudinal variation of Io's atmosphere. We find that the diurnal variations of the surface temperature affect the subsurface structure up to a depth of 0.6 m. Furthermore, we quantify seasonal effects with Io having a northern summer close to perihelion and a northern winter close to aphelion. Finally, we found that at Io's anomalous warm polar regions a conductive heat flux of at least 1.2 Wm 2 is necessary to reach surface temperatures consistent with observations.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Dott, A.‐C. UNSPECIFIED https://orcid.org/0009-0002-8605-639X UNSPECIFIED Saur, J. UNSPECIFIED https://orcid.org/0000-0003-1413-1231 UNSPECIFIED Schlegel, S. UNSPECIFIED https://orcid.org/0000-0002-4779-2813 UNSPECIFIED Strobel, D. F. UNSPECIFIED https://orcid.org/0000-0002-0944-8675 UNSPECIFIED de Kleer, K. UNSPECIFIED https://orcid.org/0000-0002-9068-3428 UNSPECIFIED de Pater, I. UNSPECIFIED https://orcid.org/0000-0002-4278-3168 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-806040
Identification Number:	10.1029/2024JE008869
Journal or Publication Title:	Journal of Geophysical Research: Planets
Volume:	130
Number:	7
Page Range:	pp. 1-25
Number of Pages:	25
Date:	5 July 2025
Publisher:	Wiley
ISSN:	2169-9097
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Institute for Geophysics and Meteorology
Subjects:	Earth sciences Geography and travel
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/80604