Characteristics of the convective bursts and their relationship with the rapid intensification of Super Typhoon Maria (2018)

ABSTRACT For Super Typhoon Maria (2018), the multi-intensity change stages are identified and reproduced by numerical simulation. It is rather difficult to perform a perfect simulation for such a repeatedly reinforced typhoon during its long life-cycle and remote path. In this study, the rapid intensification (RI) episode is focused on to investigate the convective burst (CB) characteristics and the relationship between the CBs and the RI of Maria. For Typhoon Maria, 1) the spatial pattern of the inner-core CBs in distinct shear-relative quadrants, instead of the overall inner-core CBs frequently used in previous studies, presents cyclonic rotation from downshear to upshear quadrants during RI, producing a higher efficiency for tropical cyclone (TC) spinup, which accelerates the RI process. 2) Dual meanings/relationships exist between CBs and RI for Maria, in contrast to the previous argument that CBs might be an indicator or a precursor to RI. The sudden growth of CBs prior to RI provides a precursor for the upcoming RI. Additionally, the appearance of the CB peak soon after RI indicates RI could lead to more intensive deep convections. The overlap of CBs with high inertial stability inside the radius of maximum wind plays a significant role in the RI of TCs. 3) The synoptic attributions to CBs are also explored for the entire troposphere, fitting in the bottom-up thinking of convection growth. The CBs might be associated with high convective available potential energy in the boundary layer, a strengthening of the deep-layer secondary circulation, and an enhanced upper-level eddy momentum flux convergence.