Determining solar effects in Neptune’s atmosphere

Aplin, K. L. and Harrison, R. G. ORCID: https://orcid.org/0000-0003-0693-347X (2016) Determining solar effects in Neptune’s atmosphere. Nature Communications, 7. 11976. ISSN 2041-1723 doi: 10.1038/ncomms11976

Abstract/Summary

Long-duration observations of Neptune’s brightness in two visible wavelengths provide a disk-averaged estimate of its atmospheric aerosol. Brightness variations were previously associated with the 11-year solar cycle, through solar-modulated mechanisms linked with either ultra-violet (UV) or galactic cosmic ray (GCR) effects on atmospheric particles. Here we use a recently extended brightness dataset (1972-2014), with physically realistic modelling to show that rather than alternatives, UV and GCR are likely to be modulating Neptune’s atmosphere in combination. The importance of GCR is further supported by the response of Neptune's atmosphere to an intermittent 1.5 to 1.9 year periodicity, which occurred preferentially in GCR (not UV) during the mid-1980s. This periodicity was detected both at Earth, and in GCR measured by Voyager 2, then near Neptune. A similar coincident variability in Neptune’s brightness suggests nucleation onto GCR ions. Both GCR and UV mechanisms may occur more rapidly than the subsequent atmospheric particle transport.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/64213
Identification Number/DOI	10.1038/ncomms11976
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Nature Publishing Group
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