School of Atmospheric Sciences, Chengdu University of Information Technology, Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, Chengdu 610225, China.
School of Atmospheric Sciences, Chengdu University of Information Technology, Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, Chengdu 610225, China.
Sci Total Environ. 2020 Jul 15;726:138579. doi: 10.1016/j.scitotenv.2020.138579. Epub 2020 Apr 8.
The Sichuan Basin (SB) is one of the four most severely polluted regions in China in terms of air quality, and the frequent generation of temperature inversions is a key factor. The deep mountain-basin topography and the geographical location adjacent to the Tibetan Plateau combine to make the inversion characteristics of this region unique. Knowledge regarding these characteristics remains limited, however. In this study, the radiosonde data at standard pressure levels and significant levels from all SB operational radiosonde stations over 2015-2018 were used to document the climatological features of the inversions from the surface to a height of 5500 m and to evaluate the impact on local air pollutant concentrations. Results revealed that the temperature inversion in the SB is a common and year-round phenomenon. The annual inversion frequency, depth, and strength values are 74.4%, 252.2 m, and 1.3 °C/100 m, respectively. The inversions are most frequent (95.4%), deepest (289.4 m), and strongest (1.6 °C/100 m) in winter. They tend to occur at one of two heights, either below 600 m or between 2200 and 3500 m. Based on their bottom heights, the inversions were divided into three groups: surface-based inversions (SIs), elevated inversions (EIs), and lower-troposphere inversions (LTIs). Annual LTI is most frequent (63.0%) and deepest (264.7 m), while annual SI is strongest (1.8 °C/100 m). Extreme contrasts exist in the seasonal properties of different inversion types. All types of inversions play a considerable role in air pollution, resulting in a high probability of severe and very serious pollution in winter. SI has a greater impact on pollutant concentrations than EI and LTI. The frequent generation of LTIs is a unique feature of the deep SB. LITs exert a significant impact on the formation of local heavy air pollution, but have not been given sufficient attention.
四川盆地（SB）是中国空气质量四大污染最严重的地区之一，频繁出现的逆温现象是一个关键因素。深盆地地形和临近青藏高原的地理位置相结合，使该地区的逆温特征独具特色。然而，目前对这些特征的了解还很有限。在这项研究中，使用了来自 2015 年至 2018 年所有 SB 运行探空站的标准气压层和显著层的探空数据，记录了从地面到 5500 米高度的逆温气候特征，并评估了其对当地空气污染物浓度的影响。结果表明，四川盆地的逆温现象是一种常见的、全年存在的现象。年逆温频率、深度和强度值分别为 74.4%、252.2 米和 1.3°C/100 米。冬季逆温最频繁（95.4%）、最深（289.4 米）、最强（1.6°C/100 米）。它们往往出现在两个高度之一，要么低于 600 米，要么在 2200 到 3500 米之间。根据其底部高度，逆温分为三组：地表逆温（SIs）、抬升逆温（EIs）和低空逆温（LTIs）。年 LTIs 最频繁（63.0%）和最深（264.7 米），而年 SIs 最强（1.8°C/100 米）。不同逆温类型的季节性特征存在显著差异。所有类型的逆温都对空气污染有相当大的影响，导致冬季严重和非常严重污染的概率很高。SI 对污染物浓度的影响大于 EI 和 LTI。低空逆温的频繁出现是深 SB 的一个独特特征。LTIs 对当地重污染的形成有显著影响，但尚未得到足够重视。
