Dynamical model and nonextensive statistical mechanics of liquid water path fluctuations in stratus clouds

The shape and tails of the probability distribution functions of the liquid water path in stratus clouds are expressed through a model encompassing Tsallis nonextensive statistics. A model originally proposed to describe turbulent flows describes the behavior of the normalized increments of the liquid water path, at both small and large timescales, provided that the distribution of the local variability of the normalized increments can be sufficiently well fitted with a χ² distribution. The transition between the small-timescale model of a nonextensive process and the large-scale Gaussian extensive homogeneous fluctuation model is found to be at around 24 h.