三种方法统计肇庆灰霾日数的结果比较和特征分析

Comparison of the Results of Hazy Days of Zhaoqing by Three Methods and Analysis of Their Characteristics

分析了用单次法、未剔除降水日均法、日均法得到的肇庆灰霾日数变化趋势和合理性,用M-K法、累积距平曲线方法,研究了灰霾天气的变化特征及其和气象因子、污染源分布、地理环境的关系。结果表明:2006年以后,单次法统计的灰霾日数明显偏多,日均法较为科学、合理。灰霾日数与平均风速、相对湿度的变化趋势呈反相关,受地面风速、逆温层的影响最明显。1991年是灰霾天气发生突变的年份。肇庆地势西北高,东南低,主要工业区和污染排放源集中分布在东部和南部,常年盛行东北风,处于珠江三角洲的下风向,污染物容易输送影响肇庆,利于灰霾天气的形成。

In this paper, the tendency and reasonality are studied of the variation of the hazy days in Zhaoqing determined with the methods of single trial, daily mean without removing precipitation and daily mean, and by the Mann-Kendall test and the approach of accumulative anomalous curves, the characteristics of the hazy weather change and their relationships with meteorological factors, distribution of pollution sources and geographical environment are examined. The result is shown as follows. The number of hazy days increased significantly after 2016 according to the result statistically determined by the single trial ap- proach and the daily mean is a method that is most scientific and reasonable. The variation tendency of hazy days is negatively correlated with that of mean wind speed and relative humidity, most affected by surface wind speed and inversion layer. 1991 is the year when an abrupt change took place in the local hazy weather. In Zhaoqing, the terrain is higher in the northwest than in the southeast, and main industries and sources of emitting pollution are concentrated in the east and south, and northeasterly is the prevailing wind all year round. Besides, Zhaoqing is at the leeward side of the Pearl River Delta so that it is easy for pollutants to be transported there and hazy weather to form.