上海地区臭氧数值预报

基于WRF-Chem在线区域化学/传输模式构建了区域化学天气数值预报业务系统,评估了2013年5月1日至9月30日期间的1h和8h臭氧业务数值预报效果.结果表明:臭氧预报没有明显的系统偏差,预报偏差在0两侧基本呈对称分布;数值预报具有较高的准确性,其中8h臭氧的效果略好,不同时效预报的相关系数均在0.8上下,浓度平均偏差和偏差中值都只有1′10-9~2′10-9,臭氧达标日和污染日预报都有很高准确率和CSI/TS评分,首要污染物也较准确;不同时效的预报效果接近,48h时效略好,24h和72h相当;数值预报也存在一定不足,存在极个别显著偏高或显著偏低的情况,同时由于等级划分阈值的存在,等级预报的准确性明显低于浓度和分指数预报.综合地看,数值预报可以提供较为准确的臭氧预报,为空气质量预报预警业务提供有力的支撑,但分指数等级预报上仍需要进一步提高.

Numerical ozone forecasting over shanghai

A numerical chemical weather forecasting system was established and operationally implemented based on the WRF-Chem Model, an online coupled regional chemical transport model. Performance of the modeling system on daily maximum 1-hour and 8-hour ozone (1h and 8h O3) concentrations was evaluated between May 1st and September 30th, 2013. The results showed that the numerical forecasting has generally good performance. There is no substantial systematic bias in 1h and 8h O3 concentrations and correspondent IAQI in forecasts of 24h, 48h, and 72h. The correlation coefficients (R) are ~ 0.8, and the mean and median biases are around 1′10-9~2′10-9. The forecasted O3 attainment vs. pollution days as well as primary pollutants are also in good agreement with observations. The performance of 48h forecast is slightly better than that of 24h and 72h forecast, and these of the later two are generally close to each other. Meanwhile, further improvement is still needed. For example, model shows substantial biases in O3 concentrations or IAQI forecasts in some cases, and the accuracy of O3 IAQI level forecast is substantially lower than that of concentration and IAQI value forecast. In general, the numerical forecasting system shows relatively good performance in O3 forecasts during May to September, 2013, and it has the capability to support the air quality forecast over Shanghai.