不同驱动场对东亚区域再分析系统中华南台风降水影响的对比研究

使用ERA-Interim和ERA5两套再分析资料分别驱动东亚区域再分析系统(East Asia Reanalysis System,EARS),并输出2015年一年期试验再分析资料,通过评估其中3次代表性的华南登陆台风降水过程,对比不同驱动场对该系统的影响,研究发现以ERA5驱动的EARS输出结果较ERA-Interim驱动的结果更准确,尤其在丘陵和山地等复杂地形下的降水模拟改进明显。进一步用ERA5驱动的EARS输出结果与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)新一代陆面再分析资料ERA5-Land对比分析,发现ERA5-Land对于台风大尺度降水的把握更好,而EARS对中小尺度降水过程的再现更完整,特别是对沿海降水的模拟更准确。相较于ERA5-Land,EARS目前同化的观测资料有限,对物理过程参数化方案的选择仍欠准确,后续需要有针对性地改进。

Comparative study on effects of different driving fields on typhoon precipitation over South China in the East Asia Reanalysis System

The East Asia Reanalysis System (EARS) is driven by ERA-Interim and ERA5 reanalysis data, respectively, and the one-year experimental reanalysis data of 2015 are exported. By evaluating three representative typhoon precipitation processes over South China in 2015 and comparing the effects of different driving fields, it is found that the EARS results driven by ERA5 are more accurate than those driven by ERA-Interim, especially for simulated precipitation in complex terrains such as hills and mountains. Further comparative analysis is conducted between the EARS results driven by ERA5 and ERA5-Land, the new generation land surface reanalysis data of European Centre for Medium-Range Weather Forecasts (ECMWF), which shows that ERA5-Land has a better accuracy of large-scale typhoon precipitation, while EARS reproduces meso- and small-scale processes more completely and simulates precipitation in coastal areas more accurately in particular. In comparison to ERA5-Land, due to the present limit of assimilated observation data and inaccurate selection of physics parameterization schemes, EARS needs improvement accordingly in the future.