[A-AS03] Large-scale moisture and organized cloud systems

[AAS03-05] Quantitative analysis of cloud self-organization using Shannon's information entropy: results from radiative-convective equilibrium experiments

*Takuya Jinno¹, Hiroaki Miura¹ (1.Graduate School of Science, The University of Tokyo)

Keywords:radiative-convective equilibrium, organization, information entropy

The intensity of precipitation and the radiative fluxes through the atmosphere change profoundly depending on the spatio-temporal distribution of clouds, and have a significant impact on the global climate. In order to physically understand these changes, it is useful to separate the complex mechanisms involved in the organization of clouds and precipitation into hierarchical processes. In this study, as an index to quantify the degree of cloud self-organization, Shannon's information entropy, which is a measure representing how much the spatio-temporal patterns are “disordered", is calculated from the orthogonal function expansion. As a result of the analysis of outgoing longwave radiation and precipitable water data obtained from the radiative-convective equilibrium experiment with the cloud-resolving model, each mode of variability, such as the drying trend of the entire experimental domain and the emergence of moist areas with active convection, was isolated. In addition, it was confirmed that the value of information entropy decreased in conjunction with the formation of cloud clusters. The results suggest that information entropy is beneficial for analyzing self-organization phenomena that appear under idealized conditions with high resolution.