H2 S3(1) and S4(1) transitions in the atmospheres of Neptune and Uranus - Observations and analysis

The present observational results for Neptune's S3(1) and S4(1) H2 lines show the former line's measured equivalent width to be the same as for this feature in Uranus, repeating the equality already established between the two planets for the latter feature. It is also noted that the observed ratio of the H2 S3(0)/S3(1) lines for Neptune's atmosphere is reproduced by models belonging to the family of models created by Baines and Smith (1990); by comparison with the earlier Uranus models of Baines and Bergstrahl (1986), the greater continuum absorption of Neptune is responsible for the increased S3(0)/S3(1) line ratio near 0.82 microns.