Cloud-radiative interaction (CRI) is a fundamental process that modulates large-scale circulations and intraseasonal variability, including the Madden-Julian Oscillation (MJO). In this study, we investigate how large-scale circulations and MJO respond to CRI intensity changes and provide insights into the underlying mechanisms, utilizing the aquaplanet configuration in the Community Earth System Model 2 (CESM2). By tuning DCS, a cloud microphysics parameter, to enhance CRI, we demonstrate that it is linked to a strengthened Hadley cell, an augmented moisture amount, and a stronger equatorward intertropical convergence zone (ITCZ) with more tropical precipitation. Furthermore, the intensified CRI directly influences the MJO scale, leading to the simulated MJO-like mode displaying intensi...[ Read more ]

Cloud-radiative interaction (CRI) is a fundamental process that modulates large-scale circulations and intraseasonal variability, including the Madden-Julian Oscillation (MJO). In this study, we investigate how large-scale circulations and MJO respond to CRI intensity changes and provide insights into the underlying mechanisms, utilizing the aquaplanet configuration in the Community Earth System Model 2 (CESM2). By tuning DCS, a cloud microphysics parameter, to enhance CRI, we demonstrate that it is linked to a strengthened Hadley cell, an augmented moisture amount, and a stronger equatorward intertropical convergence zone (ITCZ) with more tropical precipitation. Furthermore, the intensified CRI directly influences the MJO scale, leading to the simulated MJO-like mode displaying intensification, slower propagation, and a smaller zonal scale. However, the changes in MJO-like mode associated with CRI intensification are not dominated by the indirect effects of mean state changes through moist static energy (MSE) advection due to the offset effects of horizontal and vertical advection. Instead, the MJO-scale CRI feedback plays the most essential role. Those changes in MJO-like mode are predominantly attributed to the increased radiative heating and stronger convection induced by cloud microphysics, zonal scale selection at lower wavenumbers, the interplay between different waves with different scales, and other processes.