Tropical cyclones (TCs) can develop spontaneously under uniform boundary conditions on an f-plane (Bretherton et al., 2005). Based on the study of convective aggregation, previous research has diagnosed the spontaneous TC genesis and development as an increase of spatial variance of vertically integrated moist static energy (MSE) (e.g., Wing et al. 2016), which does not resolve the vertical dimension. Here, we present a novel vertically resolved MSE (VR-MSE) framework to study convective aggregation and TC genesis (Yao, Yang and Tan 2021). This framework explicitly illustrates the relative importance of diabatic and adiabatic processes at different altitudes.

We find that adiabatic processes (i.e., circulations) promote TC initiation, while surface fluxes dominate the MSE variance production in the intensification periods. This result broadly agrees with previous studies (e.g., Wing et al. 2016). We further show that the vertical layer between 2 and 6 km is key to TC genesis and intensification, where both the growth rate and the production of MSE variance maximize, having the largest impact on the development of TCs. Meanwhile, radiation between 10 and 12 km also makes a positive contribution to TC intensification. This VR-MSE framework illustrates TC development processes with the vertical dimension, complementing the previous vertically integrated MSE analysis. We will also show ensemble and sensitivity experiments to test the robustness of our results.