基于FGOALS-f3模式的热带气旋活动特征及模拟偏差分析

Tropical cyclone activity characteristics and simulation bias analysis based on FGOALS-f3 model

  • 摘要: 高分辨率模式比较计划(HighResMIP)是第六次国际耦合模式比较计划(CMIP6)的新增项目,在此计划框架下,资料与方法研究利用2002–2014年中国气象局CMA最佳路径数据集、GPM IMERG降水产品及ERA5再分析资料目的对比了FGOALS-f3气候模式的高低分辨率版本在模拟热带气旋路径、强度及降水方面的表现,并揭示其模拟偏差的成因。结果结果表明,随分辨率的提升,该模式在热带气旋频数、强度上的模拟能力有所提升。具体而言,FGOALS-f3高分辨率版本模拟的热带气旋路径频数与实际观测的相关系数从0.85提升至0.90;且能准确模拟出风速超过53 m/s的超强台风,而低分辨率版本则难以模拟风速超过41.5 m/s的强台风。在降水模拟上,高分辨率版本模拟的TC降水在空间分布与相对贡献率上也有所改善,空间上能更合理的模拟洋面上的降水量,TC降水贡献率较低分辨率模式提高了18.02%。结论研究表明,这些改善的主要成因在于高分辨率版本能够更好地模拟涡度的区域分布及垂直风切变等大尺度环境因子。但是该模式在岛屿降水模拟方面存在明显高估,尤其是高分辨率版本,最大高估比例达到121%。这可能是由于高分辨率模式高估了岛屿地形的动力抬升作用及岛屿上方的水汽辐合所致。未来模拟应针对海岛地形降水的高估进一步优化。

     

    Abstract: The High Resolution Model Intercomparison Project (HighResMIP) is a new component of the Sixth Coupled Model Intercomparison Project (CMIP6). Within this framework, this study employs the China Meteorological Administration (CMA) Best Track Dataset (2002–2014), the GPM IMERG precipitation product, and ERA5 reanalysis data to compare the performance of high- and low-resolution versions of the FGOALS-f3 climate model in simulating tropical cyclone (TC) tracks, intensity, and precipitation, and further investigates the sources of simulation biases. The results show that with increased resolution, the model’s ability to simulate TC frequency and intensity is improved. Specifically, the correlation coefficient between simulated TC track frequency and observations rises from 0.85 to 0.90 in the high-resolution version; moreover, the high-resolution model is able to capture super typhoons with wind speeds exceeding 53 m/s, whereas the low-resolution version fails to reproduce strong typhoons with wind speeds greater than 41.5 m/s. In terms of precipitation, the high-resolution version demonstrates improvements in both the spatial distribution and relative contribution of TC rainfall, more realistically capturing precipitation over the ocean, and increasing the TC rainfall contribution rate by 18.02% compared with the low-resolution model. These improvements are mainly attributed to the high-resolution model’s better representation of regional vorticity distribution and vertical wind shear, which are key large-scale environmental factors. However, the model significantly overestimates island precipitation, particularly in the high-resolution version, where the maximum overestimation reaches 121%. This bias is likely due to the model’s overestimation of orographic uplift effects and moisture convergence over islands. Future simulations should focus on reducing the overestimation of precipitation associated with island topography.

     

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