Global Four-Band Spectral Classification of Jupiter's Clouds: Color/Albedo Units and Trends

Abstract

Voyager 2 digital images of Jupiter have been used to construct a global data base of cloud reflectance (normal albedo) in four spectral bands: three wideband "colors" with effective wavelengths at 431 nm (VI), 564 nm (GR), and 599 nm (OR), plus the narrowband CH4 filter cen tered at 621 nm. This data base has been spectrally classified at 0.5° resolution (625 km at Jupiter's equator) to separate the complex scene into cloud color/albedo units on a pixel-by-pixel basis, revealing 20 distinct and 5 tentative units. These include both large, globally dis tributed units and very small, localized units. Global color maps and unit membership maps in printed and reprojected video form are used to highlight associations and trends. Of note are the common spectral properties of areas within white ovals and zones, and within brown barges and belts, but the spectral uniqueness of the Great Red Spot, barge cores, and other small features.