Fourier domain shape analysis methods: A brief review and an illustrative application to rainfall area evolution

Morphological shape analysis techniques offer valuable tools for the study of several hydrologic and atmospheric processes. Detailed description of patterns, as well as evolution and comparison of patterns can be efficiently performed in the Fourier domain and by means of a finite number of Fourier descriptors. In this technical note we present a brief summary of three Fourier domain shape analysis methods: the complex plane method, the angular direction method, and the polar coordinates method. We illustrate the use of the complex plane method for studying the evolution of rainfall areas within a radar‐depicted rainfall field for the purpose of short‐term precipitation forecasting.