Wang Ying, Zhi Xie-Fei, Bai Yong-Qing, Dong Fu, Zhang Ling
Key Laboratory of Meteorological Disasters, Ministry of Education, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Weather Online Institute of Meteorological Applications, Wuxi 214000, China.
Huan Jing Ke Xue. 2022 Aug 8;43(8):3913-3922. doi: 10.13227/j.hjkx.202110137.
The dominant transportation and accumulation patterns of heavy PM pollution events over the Yangtze River middle basin were identified based on the obliquely rotated T-mode principal component analysis (PCT) method and the daily mean surface pressure. The heavy PM pollution events over the Yangtze River middle basin during 2015-2019 were divided into four patterns, namely, PCT1:high-pressure bottom transport pattern (number of days:41 d, accounting for 55.4% of the total heavy PM pollution days), PCT2:low-pressure convergence accumulation pattern (12 d, 16.2%), PCT3:high-pressure static stability accumulation pattern (11 d, 14.9%), and PCT4:high-pressure rear transport pattern (10 d, 13.5%). Regional transport patterns (PCT1 and PCT4) accounted for 69% of the total heavy PM pollution days and were the major pattern of heavy PM pollution in the Yangtze River middle basin. PCT1 occurred most frequently among the four patterns, accompanied with strong northerly winds, which could drive the rapid transportation of pollutants from the upstream areas and cause the explosive increase in PM over the Yangtze River middle basin. The PM pollution events in the transport corridor, including Xiangyang, Jingmen, and Jingzhou, exhibited a 12-hour lag feature. Most parts of northern China were the source of PM, especially in central and northern Henan and western Shandong. The PCT4 transport pattern was featured by the low-level easterly winds, and the pollution level rose quickly. The PCT2 and PCT3 were characterized by the low ground wind speed, associated with the low-level horizontal convergence and subsidence. Such synoptic conditions were favorable for the accumulation of local PM pollution, and the pollution rise rate was slower, and the duration was longer than those of other patterns.
基于斜交旋转T型主成分分析（PCT）方法和日平均地面气压，确定了长江中游流域重污染颗粒物（PM）污染事件的主要输送和累积模式。2015 - 2019年长江中游流域的重污染颗粒物污染事件分为四种模式，即PCT1：高压底部输送模式（天数：41天，占重污染颗粒物污染总天数的55.4%），PCT2：低压辐合累积模式（12天，16.2%），PCT3：高压静稳累积模式（11天，14.9%），以及PCT4：高压后部输送模式（10天，13.5%）。区域输送模式（PCT1和PCT4）占重污染颗粒物污染总天数的69%，是长江中游流域重污染颗粒物污染的主要模式。PCT1在四种模式中出现频率最高，伴有强劲北风，可驱使上游地区污染物快速输送，导致长江中游流域PM急剧增加。包括襄阳、荆门和荆州在内的输送走廊中的PM污染事件呈现出12小时的滞后特征。中国北方大部分地区是PM的来源地，尤其是河南中部和北部以及山东西部。PCT4输送模式的特点是低空东风，污染水平迅速上升。PCT2和PCT3的特点是地面风速低，与低空水平辐合和下沉有关。这种天气形势有利于本地PM污染的累积，污染上升速率较慢，持续时间比其他模式更长。
