Differential rotation and cloud texture: analysis using generalized scale invariance

Abstract

Using visible and infrared satellite cloud images and the formalism of generalized scale invariance (GSI), the authors attempt to quantify the anisotropy for cloud radiance fields in the range 1-1000 km. The statistical translation invariance of the fields is exploited by studying the anisotropic scaling of lines of constant Fourier amplitude. This allows the investigation of the change in shape and orientation of average structures with scale. For the three texturally - and meteorologically - very different images analyzed, three different generators of anisotropy are found that generally reproduce well the Fourier space anisotropy. The authors conclude that while cloud radiances are not isotropic (self-similar), they are nonetheless scaling. -from Authors