Extreme rainfall event in December 2021 over Peninsular Malaysia

Andy Chan - Dean of Engineering, Robert Gordon University Cambridge Fluids Network - fluids-related seminars 27 February 2024 11:00am Chemistry Dept, Unilever Lecture Theatre and Zoom During December 2021, a heavy rainfall/flooding event (HRF) occurred over Peninsular Malaysia, which causes unprecedented volumes of rainfall on the West and East coast of Peninsular Malaysia (i.e. Pahang and Selangor) with significant socio-economical and financial losses. Two disturbances have been found to play key roles in this HRF event, which are cold surge vortex and Typhoon Rai. Firstly, a low-level north-easterly cold surge interacts with an easterly surge over the southern South China Sea, causing the vortex to form over East Malaysia. The vortex was then enhanced and transported towards Peninsular Malaysia by a strong easterly wind from the outer wind of Typhoon Rai over the Philippines. It further passed through the Titiwangsa mountain range over the middle of Peninsular Malaysia, resulting in an intense rainfall along the west coast. Moreover, biomass burning aerosols were suspected to be able to intensify the precipitation. Thus, the impact of biomass burning on the extreme event was carried out by using WRF-Chem numerical simulation modelling. By comparing the precipitation temporal and spatial distribution of two model scenarios (model simulations with and without biomass burning inventory), biomass burning aerosols reflect only a minor impact on intensifying or delaying the rainfall event. The extreme rainfall event was mainly caused by the cold surge induced disturbance and Typhoon Rai. ------------------------------------------------------------ Topic: CAS Seminar: Prof Andy Chan Time: Feb 27, 2024 11:00 AM London Join Zoom Meeting https://us02web.zoom.us/j/89826306833?pwd=cnNHSG9OWHRjVngzMGVMc2F0NnA4dz09 Meeting ID: 898 2630 6833 Passcode: 662640