Critical phenomena in atmospheric precipitation

TL;DR

This paper reports the observation of critical phenomena in atmospheric precipitation on large scales, linking them to self-organized criticality and phase transitions, with implications for meteorology and understanding of SOC.

Contribution

It characterizes atmospheric precipitation as a physical system displaying self-organized criticality through underlying phase transitions, a novel insight in meteorology.

Findings

Precipitation exhibits critical phenomena on scales of tens of kilometers.

Evidence links quasi-equilibrium states to critical points of phase transitions.

First physical characterization of SOC in atmospheric systems.

Abstract

Critical phenomena near continuous phase transitions are typically observed on the scale of wavelengths of visible light[1]. Here we report similar phenomena for atmospheric precipitation on scales of tens of kilometers. Our observations have important implications not only for meteorology but also for the interpretation of self-organized criticality (SOC) in terms of absorbing-state phase transitions, where feedback mechanisms between order- and tuning-parameter lead to criticality.[2] While numerically the corresponding phase transitions have been studied,[3, 4] we characterise for the first time a physical system believed to display SOC[5] in terms of its underlying phase transition. In meteorology the term quasi-equilibrium (QE)[6] refers to a state towards which the atmosphere is driven by slow large-scale processes and rapid convective buoyancy release. We present evidence here that QE, postulated two decades earlier than SOC[7], is associated with the critical point of a continuous phase transition and is thus an instance of SOC.