CMA-MESO关键技术集成及应用

基于GRAPES-MESO 10 km系统，提高模式动力框架计算精度和稳定性，选择调试适合高分辨率模式的物理过程参数化方案组合，建立面向数值天气预报的全国雷达质量控制拼图系统，通过云分析系统融合全国三维组网反射率因子拼图，建立面向中小尺度系统的对流可分辨同化系统和陆面资料同化系统，实现雷达径向风、风廓线雷达、FY-4A成像仪辐射率、卫星云导风、卫星GNSSRO、地面降水观测以及近地面资料等非常规局地稠密资料的同化应用，发展快速循环技术，建立全国3 km间隔3 h的快速循环同化预报系统——CMA-MESO（GRAPES-MESO 3 km）并实现业务化运行。2020年6—9月汛期业务检验结果表明:CMA-MESO预报的近地面要素（降水、2 m温度、10 m风场）检验评分全面超越GRAPES-MESO 10 km结果；CMA-MESO的24 h累积降水TS评分略低于欧洲中期天气预报中心（ECMWF）的结果，但逐3 h累积降水预报TS评分尤其是对于较大降水阈值评分明显优于ECMWF结果；同时，对于能够表征模式对降水时空精细化特征预报能力的降水频次和降水强度等检验，CMA-MESO对我国汛期的预报准确率超过了ECMWF细网格模式结果。

Key Technologies of CMA-MESO and Application to Operational Forecast

To meet the requirement of numerical weather prediction for local severe convective weather, especially disastrous weather and extreme weather events, based on GRAPES-MESO 10 km system, many works have been completed, which include improving the calculation accuracy and stability of the model dynamic framework, selecting and testing the physical parameterization schemes suitable for high-resolution model, establishing a national radar quality control preprocess system, applying the national (SA/SB/CB) three-dimensional network mosaic data through the cloud analysis system, establishing a convective resolvable assimilation system and land surface data assimilation system for small and medium-scale systems, implementing the assimilation and application of unconventional local dense data such as radar radial wind, wind profile radar, FY-4A imager emissivity, satellite cloud motion wind, satellite GNSSRO, surface precipitation and the near surface data, and developing the rapid cycle technology. By integrating all the jobs mentioned above, the nationwide rapid analysis and forecast system CMA-MESO (GRAPES-MESO 3 km)has been established and put into operational run since June 2020 with 3 km horizontal resolution and 3 h time interval. The operational verification results in flood season from June to September of 2020 show that the forecasts of near surface elements (precipitation, 2 m temperature and 10 m wind) of CMA-MESO forecast surpass the results of GRAPES-MESO 10 km system, and the threat score for 3 h accumulated precipitation forecast is outstanding. The threat score for 24 h accumulated precipitation of CMA-MESO is slightly worse than the result of ECMWF, but the threat score for 3 h accumulated precipitation forecast is significantly better. For the precipitation exceeding 10.0 mm, CMA-MESO performs better than ECMWF within all the lead times, and the advantages are more obvious with the increase of precipitation threshold. Compared to ECMWF, CMA-MESO shows more obvious advantages on daytime forecast. For 25 mm precipitation threshold, the improvement rate exceeds 50% in most of the daytime and reaches about 100% in the later stage of forecast. The spatial distribution of mean 24 h accumulated precipitation predicted by CMA-MESO and ECMWF models is close to the observation, but the amount predicted by CMA-MESO is slightly larger. The frequency and intensity of precipitation simulated by CMA-MESO, which can characterize the ability of model to predict the spatial-temporal fine characteristics of precipitation, are consistent with observation in terms of both horizontal distribution and magnitude. The comprehensive performance of CMA-MESO in flood season in China exceeds that of ECMWF fine grid model.