Study on the Precursor Signal Capturing of Unfavorable Weather: Months/Years in Advance to Ultra-Early Forecast for Hourly Transient Weather Changes during the Beijing Winter Olympics

Table 4

Weather phenomena and atmospheric aerosol elements of the pollution process in Zhangjiakou for February 2017 and February 2021.

Pollution processes in ZJK for Feb 2017	Visibility	Weather: haze
① 19:00 03 Feb to 00:00 04 Feb	① Vis_mini. = 1.3 km	√
② 00:00 15 Feb to 00:00 16 Feb	② Vis_mini. = 2.1 km	√
③ 00:00 21 Feb to 00:00 22 Feb	③ Vis_mini. = 1.2 km	√
④ 00:00 27 Feb to 00:00 28 Feb	④ Vis_mini. = 6.3 km	√
Pollution processes in ZJK for Feb 2017	Factor of aerosols and PLAM
① 20:00 02 Feb to 12:00 04 Feb	① PLAM = 193
	PM2.5 = 203 μg/m^3
	SO2 = 184 μg/m3	S = 4.0%
② 07:00 15 Feb to 19:00 16 Feb	② PM2.5 = 168 μg/m^3	NO2 = 182 μg/m^3
	SO2 = 245 μg/m^3
③ 00:00 21 Feb to 08:00 22 Feb	③ PM2.5 = 168 μg/m^3	SO2 = 107 μg/m^3
	PLAM = 191, S = 2.6%
④ 17:00 25 Feb to 17:00 27 Feb	④ O3 = 109 μg/m^3
	SO2 = 103 μg/m^3
Pollution processes in ZJK for Feb 2021	Visibility	Weather: Haze
① 06:00 11 Feb to 19:00 15 Feb	① Vis_mini. = 1.3 km	√
② 06:00 26 Feb to 00:00 28 Feb	② Vis_mini. = 1.1 km	√
Pollution processes in ZJK for Feb 2021	Factor of aerosols and PLAM
① 06:00 11 Feb to 19:00 15 Feb	① PM2.5 = 472 μg/m^3
	NO2 = 106 μg/m^3, O3↑	117 µg/m^3
	PLAM = 190
② 06:00 26 Feb to 00:00 28 Feb	② PM2.5 = 198 μg/m^3
	PLAM = 185, S = 5.7%
	O 3 = 113 μg/m^3