Self-organized criticality in cumulus clouds

TL;DR

This paper demonstrates that fair weather cumulus clouds exhibit self-organized criticality and conformal symmetry, supported by observational data and simulations, contrasting with turbulence characteristics.

Contribution

It reveals that cumulus clouds are driven by SOC and conformal symmetry, providing a new physical understanding and simulation approach for cloud formation.

Findings

Cloud images show SOC behavior with specific exponents.

Cumulus clouds exhibit conformal symmetry with c=-2 CFT.

Simulations replicate observed exponents using Navier-Stokes, diffusion, and CML models.

Abstract

The shape of clouds has proven to be essential for classifying them. Our analysis of images from fair weather cumulus clouds reveals that, besides by turbulence they are driven by self-organized criticality (SOC). Our observations yield exponents that support the fact the clouds, when projected to two dimensions (2D), exhibit conformal symmetry compatible with $c=-2$ conformal field theory (CFT), in contrast to 2D turbulence which has $c=0$ CFT. By using a combination of the Navier-Stokes equation, diffusion equations and a coupled map lattice (CML) we successfully simulated cloud formation, and obtained the same exponents.