The Role of Middle Tropospheric Mesoscale Convective Vortex in the Genesis of Typhoon Durian (2001)—Diagnostic Analysis of Simulated Data

Based on the successful numerical simulation of typhoon Durian (2001) with the PSU/NCAR nonhydrostatic mesoscale model (MM5), the authors diagnose the contributions of middle tropospheric mesoscale convective vortex (MCV) to the Durian's genesis using the high resolution data (6 km) produced by MM5. The results show that the MCV have three important performances. First, playing the role of mesoscale organization system, the second vertical cycle of MCV transports the convective hot towers to the central area of MCV, making the hot towers have the trend to contest or merge each other, so that some hot towers become stronger or died. The feedback of the collective effect of hot towers makes the MCV intensify or maintain, and the MCV further pushes the assembling, merging and axisymmetrization of hot towers. Second, playing the role of memory system, because the MCV have the longer life time than individual hot tower, the MCV can reserve the heat, moisture, and vorticity left by the died hot towers, which will make the MCV area favorable to the TC genesis, and ultimately become the ‘embryo’ of Durian. Third, the MCV, the low tropospheric trough (vortex), and the hot towers conduct together the vertical uniformization between the lower and middle tropospheric systems through their interaction.