Convective Self‐Aggregation Occurs Without Radiative Feedbacks in Warm Climates

Abstract

Previous research showed that radiative feedbacks are essential to the spontaneous development of convective aggregation (CSA) in idealized atmosphere models. We find that the contribution of radiative feedbacks decreases with warming and that, in warm climates, CSA occurs without radiative feedbacks. We perform 2D simulations in different climates using a cloud‐resolving model and use a layerwise moist static energy (LMSE) framework to quantify the contribution of radiative feedbacks to the increase of LMSE variance, which characterizes the development of CSA. The result shows that positive radiative contribution dominates the LMSE variance production when SST is below 300 K; when SST exceeds 300 K, adiabatic contribution shifts from negative to positive and dominates the variance production. Then we turn off radiative feedbacks by horizontally homogenizing radiative heating rates at all model levels. CSA still occurs in warmer climates (310–320 K). This result agrees with the LMSE diagnosis and additional 3D simulations.

Vertically resolved analysis of the Madden-Julian Oscillation highlights the role of convective transport of moist static energy

“…Our diagnostic framework follows Yao and Yang (2023). The underlying assumption of the analysis is that the MJO has a characteristic vertical structure that is fundamental to the dynamics of the MJO.…”

“…Let's consider the tendency generated by sub-grid scale vertical MSE transport Q c : To complement the vertically integrated analysis, we present a vertically resolved MSE analysis to study the MJO. This framework was first developed to study convective selfaggregation (Yao et al, 2022;Yao & Yang, 2023) and was subsequently applied to study tropical cyclones (B. Zhang et al, 2022).…”