Fractal

Precipitation : space

The easiest way to calculate the fractal dimension of an object is the box-counting method introduced above. In the case of the precipitations, the meteorological radar provides an instantaneous images of the precipitation area with different rain rates. These zones appear as fragmented, thus the image can be interpreted as a fractal object.

Fractal dimension calculation: (a) Original radar image (Nîmes, France); (b) Filtered image with resolution 256X256 pixels; (c) aggregated image to 128X128 pixels, (d) aggregated image to 64X64 pixels ; (e) aggregated image to 32X32 pixels. [J.L Macor 2007]

Applying the box-counting method on the aggregated images, one can found there exist a scale invariance law, with an exponent which represent the fractal dimension.

Log-Log for different resolutions of the radar image. The straight line indicate the scale invariance propriety, the fractal dimension of the image is Df = 1.75.
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