Variation of Methane Absorption over the Jovian Disk from the Data of Zonal CCD Spectrophotometry

A comprehensive zonal spectrophotometry of Jupiter's disk was performed with a prism spectrograph and an ST-6V CCD camera mounted on the 1-m telescope at the Assy observatory in 1997 and 1998. In addition to the spectra of the central meridian and the equatorial belt, 10 sets of spectrograms of 37 to 39 of Jupiter's zones were recorded with a step of about 1.2″ (each set contained the measurements of absorption bands for approximately 3200 points of Jupiter's disk). Based on these data, an atlas of zonal variations in the central depths Rνof the methane absorption bands in the wavelength range 560–950 nm is compiled and numerical-contour and 3D half-tone maps representing the distributions of Rνover the disk are constructed. For most zones, methane absorption changes slightly from the central meridian to the limb. The intensities of strong and moderate methane bands exhibit pronounced zonal variations, whereas the intensity of a relatively weak band at 619 nm varies more chaotically. This effect is likely due to the fact that, at the effective depth where the weaker bands are formed, the medium is more homogeneous, since the convective and turbulent mixing is more intense at this depth.