Comparing Convective Self-Aggregation in Idealized Models to Observed Moist Static Energy Variability near the Equator

Idealized cloud-permitting simulations of radiative-convective equilibrium (RCE) have become a popular tool for understanding the physical processes leading to horizontal variability of tropical water vapor and rainfall. However, the applicability of idealized simulations to nature is still unclear given that important processes are typically neglected, such as lateral vapor advection by extratropical intrusions, or interactive ocean coupling. Here, we exploit spectral analysis to compactly summarize the multi-scale processes supporting convective aggregation. By applying this framework to high-resolution reanalysis data and satellite observations in addition to idealized simulations, we compare convective-aggregation mechanisms across horizontal scales and data sets. The results affirm the validity of the RCE simulations as an analogy to the real world. Column moist static energy spectral tendencies share similar signs and scale-selectivity in cloud-permitting models and observations: Radiation increases variance at wavelengths above 1,000km, while advection damps variance at all wavelengths, and surface enthalpy fluxes mostly reduce variance between wavelengths of 1,000km and 10,000km.