Self-aggregation of convection can be considered as the simultaneous occurrence of dry patch initiation/amplification and wet patch contraction/intensification from initially uniform moisture and temperature fields. As the twin of wet patches, dry patches play an important role in moisture and energy balance during convective self-aggregation. In this study, the WRF Model is used to study the initiation of dry patches in convective self-aggregation, especially the continuous drying in their boundary layer (BL). In the dry patch BL, increased air density leads to an enhanced high pressure anomaly, which drives an amplifying BL divergent flow and induces an amplifying BL subsidence. The virtual effect of drying by subsidence counteracts warming by subsidence and the BL process, further increasing BL air density. Our analysis indicates the existence of a dry-subsidence feedback, which leads to the initiation of dry patches in convective self-aggregation. This feedback is shown to be important even in very large-scale (3000 km × 9000 km) cloud-resolving convective self-aggregation simulations.

Interactive radiation helps accelerate tropical cyclogenesis, but the mechanism is still unclear. Using idealized numerical modeling in the radiative-convective equilibrium framework, it is revealed that interactive radiation can bring forward tropical cyclogenesis by accelerating the development of the mid-level vortex. A strong horizontal longwave radiative warming anomaly in the layer between 6 and 11 km altitudes in the vortex region, caused by large concentration of ice-phased particles at high levels, is critical to the development of the mid-level vortex. This longwave radiative warming anomaly induces more upward water vapor flux (mainly in the non-convective region) and then results in more latent heating at upper levels and more sublimation cooling at lower levels. This leads to an increase of the vertical diabatic heating gradient, and then the intensification of the mid-level vortex. A stronger upward water vapor flux also produces more condensates at upper levels and further enhances the horizontal longwave radiative warming anomaly in the upper-troposphere, constituting a positive feedback and then accelerates the tropical cyclogenesis.

Tropical cyclones (TC) are among the most destructive geophysical phenomena on earth. It is well accepted that the wind-induced surface heat exchange feedback is the most responsible mechanism for the intensification and maintenance of TCs (e.g., Emanuel, 1989Emanuel, , 1995. However, the controlling mechanisms of TC genesis are still unsettled.The critical role of radiation feedback on TC genesis has been becoming more and more appreciated in recent years (e.g.,

The prediction of tropical cyclone (TC) intensity remains a major scientific challenge. Recent studies indicate that cloud‐radiation feedback (CRF) plays a positive role in the intensification of TCs during their genesis. However, little attention has been given to how CRF affects TC intensity after genesis. This study shows that CRF may prevents TCs from attaining higher maximum intensities. The ascending motion induced by the anomalous radiative heating of TC promotes more latent heating on the outer side of the upper eyewall, resulting in a more tilted eyewall. A more tilted eyewall leads to a larger inner‐core size and less inward flux of absolute vertical vorticity within the inner core, thus preventing the TC from reaching higher intensity. This work highlights that CRF may affect TC intensity by modulating the structure of the inner‐core convection, and further advances our understanding of the interaction between radiation effect and TC dynamics.

Secondary eyewall formation (SEF) is an important topic in tropical cyclone (TC) dynamics owing to its significant influences on TC intensity and size (Houze et al., 2007;Kuo et al., 2009;Sitkowski et al., 2011;Willoughby, 1990). Typically, SEF possesses a secondary convective ring and an associated secondary low-level tangential wind maximum outside the primary eyewall (Willoughby et al., 1982), which is governed by internal dynamics but is also influenced by environmental forcings. Due to the complexity of the physical processes involved, the prediction of SEF remains a big challenge (Hazelton et al., 2018;Kossin & Sitkowski, 2009). SEF involves multi-scale internal processes, including but not limited to: the beta-skirt axisymmetrization of turbulent scale perturbations (Terwey & Montgomery, 2008); the interaction of vortex Rossby wave with vortex mean flow (Montgomery & Kallenbach, 1997;Qiu et al., 2010); the rapid filamentation effect in promoting moat region between two eyewalls (Rozoff et al., 2006); the balanced response to diabatic heating released by outer rainbands (ORBs) with enhanced inertial stability outside the primary eyewall (Rozoff et al., 2012); the unbalanced boundary layer (BL) dynamics (