| 2013~2021年邢台PM2.5重污染过程输送和增长特性 |
| 摘要点击 1515 全文点击 467 投稿时间：2022-08-05 修订日期：2022-09-13 |
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| 中文关键词 PM2.5 污染传输 暴发增长 大气环流 重度及以上污染过程(SAAP) |
| 英文关键词 PM2.5 pollution transmission explosive growth atmospheric circulation severe and above pollution process (SAAP) |
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| 中文摘要 |
| 利用河北邢台2013~2021年的PM2.5、气象要素和模拟资料，着重针对重度及以上污染过程（SAAP）中PM2.5增长速率、来源及其与大气环流和风场的关联性进行分析.结果表明，2013~2021年邢台共发生PM2.5污染过程164次，SAAP 103次.地面环流中倒槽型出现概率较低，但出现污染概率最高（61.1%），其次为高压控制型；500 hPa为平直西风带控制时重度及以上污染概率最高（20.7%），槽后型次之（16.1%）.SAAP中PM2.5小时变化率（ΔPM2.5）主要在±150 μg ·（m3 ·h）-1，PM2.5小时变化率为正（+ΔPM2.5）贡献约61.7%，其中暴发增长占比约13.9%.北偏东风为与重度及以上污染关联最为紧密的风向.中等风速条件下SAAP中ΔPM2.5平均值大多低于静小风，但东偏北和南偏西部分风向区间中，中等风速ΔPM2.5平均值显著高于静小风（与污染传输有关）；较大风速对ΔPM2.5影响复杂.后向轨迹表明，SAAP中缓慢、快速和暴发增长的后向轨迹可分为北偏西、北偏东和偏南3个主要路径，随增长速度加快，北偏西气团来向占比增大.缓慢增长气团相对湿度（RH）较大（80%以上RH>50%），快速增长气团RH分布较集中（主要为35%~55%），暴发增长中的低RH （RH<50%）气团占比明显增加（约63%）.模拟表明SAAP可分为本地累积、北部偏东输送、北部偏西输送、混合输送型和偏南输送这5类，其中混合输送型占比最高，其次为北部偏西输送型.偏南输送、本地累积和北部偏东输送型中出现概率最高的高低空配置均为高空槽后配合地面均压场；北部偏西输送型中地面高压配合高空槽后出现概率最高；混合输送中多种环流配比相对均衡. |
| 英文摘要 |
| The correlation between the growth rate of PM2.5 with transport source, atmospheric circulation, and wind field were analyzed, focusing on the severe and above pollution process (SAAP) in Xingtai, Hebei Province from 2013 to 2021. The results showed that from 2013 to 2021, a total of 164 pollution processes and 103 SAAP occurred in Xingtai. In the ground circulation, although the probability occurrence of the inverted trough was low, the probability of pollution was the highest (61.1%), followed by the high-pressure control type (>50.0%). In the 500 hPa, the control of the straight westerly wind belt had the highest probability of severe and above pollution (20.7%), followed by the post-trough type (16.1%), with the highest occurrence frequency. In SAAP, the distribution of the PM2.5 hourly growth rate (ΔPM2.5) was mainly concentrated between ±150 μg·(m3·h)-1, and the PM2.5 hourly growth rate was positive (+ΔPM2.5), contributing 61.7%. Among them, the average proportion of explosive growth was 13.9% (from 2013 to 2021), and the overall trend was decreasing annually. In the full wind speed, in terms of occurrence frequency and pollution probability, north-east (NE) was the wind direction most closely related to air pollution, especially severe and above pollution. The mean value of ΔPM2.5 in SAAP was lower than that of quiet wind in most wind directions. However, in some of the east-north (EN) and south-west (SW) wind direction intervals, the mean ΔPM2.5 in moderate wind speed was significantly higher than that of quiet wind (related to pollution transmission). The impact of larger wind speed on ΔPM2.5 was more complicated. The backward trajectories showed that the backward trajectories of slow, rapid, and explosive growth in SAAP could be divided into three main paths:west-north, east-north, and south. With the acceleration of the growth rate, the proportion of the west-north air mass gradually increased. The humidity (RH) of the slow-growth air mass was relatively large (more than 80% RH>50%), the relative humidity of the rapidly growing air mass was relatively concentrated (mainly distributed in 35%-55%), and the proportion of low-humidity (<50%) air masses increased significantly (by approximately 63%) in the explosive growth. The simulation analysis showed that the types of SAAP pollution could be divided into five categories:local accumulation, east-northern transmission, north-west transmission, mixed transmission, and south transmission. Among them, the proportion of mixed transmission was the highest, followed by that of the north-west transmission. The high and low-altitude configurations with the highest occurrence probability among the southerly transmission, the local accumulation type, and the north-easterly transport type were all high-altitude trough rear type combined with ground equalization field type. Among the north-westerly type, the high-pressure on the ground with the behind trough on high-altitude had the highest probability of occurrence. In mixed transmission, the probabilities of various circulation ratios were relatively balanced. |
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