基于CFSv2的延伸期空气质量数值预报技术及效果评估

介绍了基于CFSv2产品开展空气质量数值模拟的技术方法以及基于该技术的成都市延伸期空气质量预报系统,评价了2019年9月25日至12月25日的预报结果,以2019年12月为例分析了系统对具体污染过程的预报能力。结果表明,系统AQI预报准确率为36.67%,等级预报准确率为68.93%,"时段1"的预报效果优于其余时段,但"时段2"和"时段3"在污染物浓度水平上仍然具有较高的参考价值。系统在PM2.5浓度、气温和气压的变化趋势上提供21 d左右的参考。后续工作中,将针对CFSv2产品开展气象模型参数方案优选,并尝试结合基于GFS产品驱动的常规业务数值预报产品为延伸期空气质量预报提供污染物浓度初始场,减少误差传递,从而提高延伸期空气质量预报产品的准确性和可用性。

Numerical Prediction Technology and Effect Evaluation of Extended Period Air Quality Based on CFSv2

The article introduced the technical methods of air quality numerical simulation based on CFSv2 products and the extended air quality forecast system of Chengdu based on this technology.The forecast results from September 25 to December 25, 2019 was estimated to analyze the forecast ability of the system with a specific pollution process in December 2019 as an example.Results showed that the AQI accuracy rate of the system was 36.67%, and the grade accuracy rate was 68.93%.The first time interval of each result was better than the other periods in accuracy, but second time interval and the last time interval still had high reference value in terms of pollutant concentration level.The system provided a reference of about 21 days on the trend of PM_2.5 concentration, temperature and air pressure.In the follow-up work, the optimization of meteorological model parameters should be carried out for CFSv2 products, and an attempt should be made to provide the initial field of pollutant concentration for extended air quality forecasting in combination with conventional operational numerical forecast products driven by GFS products to reduce the transmission of errors, thereby improve the accuracy and availability of extended air quality forecast products.