14:00 〜 14:15
[MIS06-02] A Case Study of a Heavy Rainfall Event Associated with Mesoscale Convective Systems under Weak Large-Scale Conditions over Mindanao, Philippines
★Invited Papers
キーワード：heavy rainfall, mesoscale convective systems, tropics, numerical modeling
A heavy rainfall event occurred over Davao City in Mindanao Island, Philippines, on 03 May 2017, which resulted in flooding in the urban area. The case event happened during the summer season when there is weak influence of large-scale forcings (e.g., monsoonal flow) over the region, and local diurnal forcing is mainly in effect. The satellite observations show the development of mesoscale convective systems (MCSs) in the region that could have brought in a large amount of rainfall. This study examines the local processes involved in the organization of MCSs by numerical simulations using the Weather and Research Forecasting (WRF) model. The numerical simulations show that the development of two meso-beta scale convective systems near the Davao region and its merging into a meso-alpha scale resulted in flood-producing rainfall. The results demonstrate that the initiation and maintenance of the MCSs were mainly influenced by local circulations (i.e., sea breeze and cold pool outflows). In addition, the complex topographical features of Mindanao Island, where a concave basin is found, greatly influenced the accumulation of moisture within the basin, which made it conducive for convection development.