Inter-Comparisons between High-Resolution Regional Model and Global Model Predictions for Severe Weather with Diagnostic Analyses of Dynamics

Project Details


The three-year (2019 August-2022 July) project, which is a subproject of the integrated project, Taiwan-Area Heavy-rainfall Prediction Experiment (TAHPEX), will apply both regional model HWRF and global model MPAS to investigate the severe rainfall associated with Mei-yu systems and typhoons over Taiwan with the field observations collected from Taiwan-Area Heavy-rain Observation and Prediction Experiment (TAHOPE) in May-September 2020. A high-resolution area of 2-km will be targeted on the vicinity of Taiwan for better resolving intense convection accompanying the Mei-yu systems and typhoons over the steep Central Mountain Range. Inter-comparisons between HWRF (18-6-2 km, nested by three domains) and MPAS (60-10-2 km, different resolutions of three zones) will be conducted in the first year (from August 2019). The observation data will be assimilated by GSI/hybrid into HWRF and MPAS to understand the benefit of the data including FORMOSAT-7 RO data in the typhoon prediction from August 2019. In the second year (from August 2020), inter-comparisons among HWRF and MPAS will be conducted with GSI/hybrid to assimilate most of the available observation data in 2020. Dynamic diagnostics including vorticity and potential vorticity budget analyses as well as momentum and angular momentum dynamic balance will be conducted for exploring the essential features of the evolving convection associated with the typhoon systems. Asymmetry decomposition of PV budget will be analyzed for both model simulations to highlight the relative role of each dynamic forcing involved in PV tendency in steering the typhoon movement and track deflection. In the third (last) year (from August 2021), the reanalysis data from TAHOPE will be utilized to understand the impact of the experimental data, topographic effect and ocean effect on the HWRF regional model prediction. For reference, NCEP FV3 global model prediction will also be conducted from the second year to provide complemental comparisons with MPAS with similar high-resolution near Taiwan area for typhoon events in 2018-2022. The important goal of this project is to realize the state-of-art capability of high-resolution regional and global models (HWRF, MPAS and FV3) in predicting severe rainfall over the steep island mountain, and better quantify their relative advantages at simulating various rainfall processes, thus providing valuable suggestions to CWB operation and model development.
Effective start/end date1/08/2031/07/21

UN Sustainable Development Goals

In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):

  • SDG 11 - Sustainable Cities and Communities
  • SDG 14 - Life Below Water
  • SDG 17 - Partnerships for the Goals


  • HWRF
  • MPAS
  • FV3
  • Mei-yu and Typhoon


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