After some experimenting and parameter tuning i finally have generated awesome couds from perlin noise.
- noise is made 4-dimentional to allow time-shift for animation
- small clouds made of perlin noise of 4 levels, scale 4, distortion 0.2
- planetary-large curles made of perlin noise of 2 levels, scale 2, distortion 1.0
- they are multiplied to make large clouds envelope little clouds
- equatorial swirl done by rotation of texture coordinate around axis (0,0,1) for 30 * cos(lattitude) ^ 2