Twelve cirrus scenes are analyzed to determine textural and structural features using LANDSAT imagery. The main structural characteristics are: 1) cirrus cloud size distributions obey a power law, with larger cloud cells (D ⩾ 1.5 km) having smaller slopes than smaller cloud elements; 2) convective-type cirrus are fractal in nature with fractal dimensions of ≈ 1.4, while stratiform cirrus clouds show bifractal behavior, with larger clouds having smaller fractal dimensions (≈1.3); 3) stratiform cirrus cloud cells have significantly larger horizontal aspect ratio than do smaller cells; and 4) structural results are not sensitive to threshold selection. The main textural characteristics are: 1) convective cirrus clouds have high contrast measures and a rapid decrease of correlation at short distances, while stratiform cirrus clouds have low contrast measures and more gradual slopes; 2) asymptotic values are good descriptors of general characteristics (macrotexture) of cloud fields, while the slopes of textural measure curves at small distances reveal information about cloud field microtexture; 3) contrast and correlation appear to be the best discriminators of cloud field structure, and their directional measures show preferred cloud field orientation; and 4) correlation measures are sensitive to threshold selection for cirrostratus cases.
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Kuo et al. (1988) studied this question.