Improvements in the GRAPES-TCM and the forecast performance analysis in 2019

Abstract

In 2019, the operational Global Regional Assimilation and Prediction System-Tropical Cyclone Model (GRAPES-TCM) was updated by adopting the characteristic parameters in the official real-time released TC data of CMA, introducing the horizontal sixth-order diffusion scheme and adjusting the operational flowchart. In the case of the Super Typhoon Lekima, the model exhibits a reliable prediction ability for the type of tropical cyclone (TC) with northwestern tracking. The track and intensity forecasts in 2019 are significantly better than those over the past five years on average. The updated model can provide a skillful forecast of landfall position and rapid weakening process. Moreover, the precipitation pattern is close to the observation. TC forecast in 2019 shows that the updated GRAPES-TCM has a smaller track error than that of the previous year, and the 24 h intensity forecasting ability is improved.

Graphical abstract

Keywords

GRAPES-TCM / vortex initialization / numerical diffusion scheme / performance analysis

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Acknowledgments

This work is supported by the National Key Research and Development Program of China (Nos. 2016YFE0109700 and 2017YFC150190X), the National Natural Science Foundation of China (Grant Nos. 41975133 and 41975067), Science & Technology Committee of Shanghai (Nos. 19dz1200101 and 19dz1201500) and the National Defense Pre-Research Foundation (No. 305090417). We also thank the support from the Typhoon Scientific and Technological Innovation Group of Shanghai Meteorological Service.

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2021 Higher Education Press