[A-AS07] Analyses and Prediction of Extreme Weather and Climate in Southeast Asia

[AAS07-P04] Numerical Simulation of Heavy Rainfall over Mindanao, Philippines

*Ma. Cathrene Lagare¹, Takeshi Yamazaki¹, Junshi Ito¹ (1.Tohoku University)

Keywords:heavy rainfall, convection, NWP

On May 3, 2017, a heavy rainfall event caused by a mesoscale convective system (MCS) resulted in flooding over Davao City in Mindanao Island, Philippines. MCSs largely contribute to the total rainfall over the tropics. However, there are still limited studies investigating the characteristics of MCSs over the Philippines. This study evaluates the mechanisms involved in the organization of convection during the heavy rainfall event using the Weather and Research Forecasting (WRF) model. More specifically, a series of numerical sensitivity experiments were performed to determine the physical processes that influence the convection initiation and development in the Mindanao region and to identify the conducive local environmental conditions for the convection organization. The case event is also chosen as there is no influence of strong large-scale background flow (e.g., monsoonal flow) over the region during the event and local diurnal forcing is mainly in effect. Preliminary results suggest that land-ocean (mountain-plain) temperature contrasts are high enough to produce sea-breeze (valley breeze) flow which increases the convergence over the mountaintops that drives the convection initiation. Further investigation on the mechanisms involved in convection development is still being explored.