2018年国家级空气质量主客观预报TS评分对比检验

目前对空气质量主客观预报效果的对比检验较少,为了解国家级空气质量主客观预报性能,利用预兆评分(threat score,TS)检验了2018年中央气象台主客观预报效果。结果表明:2018年,主(客)观预报对全国轻度及以上污染TS评分、空报率和漏报率分别为0.23~0.34(0.24~0.26)、0.37~0.43(0.39~0.41)和0.58~0.72(0.68~0.71)。说明主观预报整体上优于客观预报,但客观预报能力已接近主观预报。主客观预报的评分均在污染较重地区(京津冀及周边、汾渭平原、华中和长江三角洲地区)高于污染较轻地区(西北、西南、珠江三角洲和东北地区),在污染较重的冬季高于清洁的夏季。随着预报时效的延长,主观预报TS评分呈下降趋势,但客观预报TS评分变化不大。在污染较重的冬季,48和72 h时效客观预报TS评分高于主观预报。此外,在2018年5次重污染天气过程中,主(客)观预报对轻度、中度和重度污染的TS评分分别为0.39~0.57(0.43~0.46)、0.22~0.46(0.25~0.30)和0.10~0.34(0.10~0.18),主观预报TS评分高于客观预报的情况占了3次。随着预报时效的延长,客观预报表现更加稳定,说明客观预报能在污染过程中为预报员提供稳定参考,但对污染高值的预报能力仍需提高。

Verification of national subjective and objective air quality forecast in 2018 by TS score

Until now, few works have reported comparison results between subjective and objective air quality forecast. To understand the performances of national subjective and objective air quality forecast, operational results in 2018 from National Meteorological Center were verified by threat score (TS) method. The results showed that TS score, false alarm ratio and missed alarm ratio of subjective (objective) forecast for mild and above pollution all over China in 2018 were 0.23-0.34 (0.24-0.26), 0.37-0.43 (0.39-0.41) and 0.58-0.72 (0.68-0.71), respectively. This illustrated that subjective forecast was better than objective one, but the ability of objective forecast was close to subjective forecast. Performances of subjective and objective forecast were both better in regions with heavier pollution (Jing-Jin-Ji, Fenwei Plain, Central China and Yangtze River Delta) than in lower pollution ones (Northwestern China, Southwestern China, Pearl River Delta and Northeastern China), and so did it in the heavily polluted winter than in the clean summer. With the extension of forecast time, TS scores of subjective forecast showed a downward trend, but scores of objective forecast did not change too much. In winter with heavy pollution, TS scores of 48 and 72 hours' objective forecast were higher than those of subjective forecast. Additionally, in 5 haze processes in 2018, TS scores of subjective (objective) forecast for mild, moderate and severer pollution all over China were 0.39-0.57 (0.43-0.46), 0.22-0.46 (0.25-0.30) and 0.10-0.34 (0.10-0.18), respectively. The situation of TS scores of subjective forecast higher than objective forecast accounted for 3 times in 5 processes. But performance of objective forecast was more stable with extension of forecast time, which illustrated that objective forecast could provide stable reference to forecasters in pollution process, but its ability in dealing with high pollution needs to be improved.