Spatial and temporal variations of Jupiter's H3+ emission deduced from image analysis

Intensity distribution of H3+ emission across Jupiter's disk has been analyzed using 3.4-µm IRTF/ProtoCAM images acquired in 1992. The apparent disk emission is approximated using a mathematical function, of which parameters characterize (i) the dependence on the solar illumination angle, (ii) limb brightening consistent with the line-of-sight effect, and (iii) the latitudinal variation. A simple atmospheric model reproduces the disk emission (corrected for the line-of-sight effect) well, with H3+ emission peak in an altitude range 700–750 km above P = 600 mb level.