[A-AS02] Advances in Tropical Cyclone Research: Past, Present, and Future

[AAS02-09] Pronounced advance on typhoon track forecast with global convection-permitting model

*Jun Gu¹, Chun Zhao¹, Gudongze Li¹, Jiawang Feng¹, Mingyue Xu¹, Yubin Li², Gunghua Chen³ (1.University of Science and Technology of China, 2.Nanjing University of Information Science and Technology, 3.Institute of Atmospheric Physics, Chinese Academy of Sciences )

Keywords:global convection-permitting models, Typhoon In-fa, track forecast, variable-resolution model

Successfully forecast track and strength of typhoon would be very important to assess its impact and make mitigation strategy. However, the advance of typhoon track forecasting is very slow if not decelerating in last decades. A few approaches have been applied to improve the skill of numerical weather prediction, with one as increasing model horizontal resolution that could theoretically improve the solving of dynamical equations and reduce the uncertainties from sub-grid physical parameterization. The typhoon In-Fa in 2021 was recognized as one of the top ten weather and climate events in China due to its prolonged duration and severe impact over the continent. Its slow moving speed and complex track make it difficult to be forecasted successfully. Our results show that global convection-permitting forecast can overwhelm the global forecasts at the horizontal resolutions of 15 km and 60 km in terms of the typhoon track. Particularly, the global convection-permitting forecast is also much better than the global forecast with regional refinement at convection-permitting resolution that covers the entire typhoon track, due to better forecasted large-scale circulation in the former one. Multiple global forecasts with regional refinements at different regions reveal that the improvement from global convection-permitting forecast results from its better performance on forecasting subtropical high, cold vortex, neighboring typhoons, and monsoon depression at higher-resolution. Our results imply that it is critical to increase the model resolution to convection-permitting scale covering not only the region with typhoon track but also the regions with the systems interacting with typhoon in order to successfully forecast typhoon track.