银川市一次连续PM_(2.5)重污染天气特征分析及长期预报方法研究

Analysis of characteristics and long-term forecasting methods for a continuous PM_(2.5)heavy pollution weather in Yinchuan

利用同期多源观测资料,对2020年1月银川市持续重污染天气过程中的气象条件、扩散特征及前期环流指数特征进行了综合分析。结果表明:2020年1月持续重污染天气过程是实行新标准以来仅次于2013年1月的PM_(2.5)超标的重污染天气,具有持续时间长、污染等级高的特点;2020年1月气温异常偏高、风速偏小、相对湿度偏大,天气系统稳定少动且持续时间长,是造成PM_(2.5)异常超标的主要原因之一;1月PM_(2.5)月浓度值同850 hPa东太平洋信风指数、北太平洋副高北界位置指数等前期环流特征因子具有较好的相关性,建立的银川市1月PM_(2.5)月浓度预测模型,可提前30 d作出预报且预报结果与实际一致,可为重污染天气预警工作提供参考。

The meteorological conditions,diffusion characteristics and circulation index characteristics during the continuous heavy pollution weather in Yinchuan in January 2020 were comprehensively analyzed by using multi-source observation data in the same period.The results showed that the continuous heavy pollution weather process in January 2020 was only better than that in January 2013 since the implementation of the new standard with a long duration and serious pollution.In January 2020,the abnormal high temperature,the relatively low wind speed,the high humidity,the stable weather system and long duration were the main reasons for abnormal exceeding of PM_(2.5).The monthly PM_(2.5)concentration in January had a good correlation with East Pacific 850 mb Trade Wind Index,Pacific Subtropical High Northern Boundary Position Index,and other pre-circulation characteristic factors.The prediction model of PM_(2.5)concentration in Yinchuan in January could be accomplish the forecast 30 days in advance and the forecast result was consistent with the reality,thus providing a reference for the early warning of heavy pollution weather.