The Guanzhong Basin (GZB) has exhibited an obvious air pollution zone in the cold season in recent years. The variability of haze days combined with dynamic circulation was investigated using meteorological observation data and ERA-5 reanalysis data. The results show that large-scale and mountain-valley circulation, local meteorological factors and mountains affected the variability of severe haze events. The GZB is surrounded by complicated mountain conditions, with the Loess Plateau in the north, the Qinling Mountains in the south, highlands in the west and a valley plain in the east. The analysis showed that the formation and development of long-lasting severe haze events rely largely on the persistent south and east winds at a large scale. Owing to the complex effects of terrain, a weak convergence-stable stratification-divergence distribution is formed in the GZB in the vertical profile from the surface to the middle troposphere. A stable stratification exists near 850 hPa with features of near-zero vertical speed and an evident inversion layer. In this atmospheric environment, air pollution worsens until the northwest wind intensifies. In addition, mountain-valley circulation plays an important role in the diurnal variability of haze. During the day, the valley breeze dissipates pollutants, decreasing the PM_2.5 concentrations. At night, the mountain breeze transports pollutants into the basin, and the PM_2.5 concentrations increase. This study illustrates that terrain conditions are responsible for the formation of haze in the GZB, and efforts should be made to reduce emissions in the region.

近年来，关中盆地在寒冷季节表现出明显的空气污染带。利用气象观测数据和ERA-5再分析数据，研究了雾霾天与动态环流的变化关系。结果表明，大规模的山谷环流，当地的气象因素和山脉影响了严重霾事件的变化。GZB周围是复杂的山脉，北部是黄土高原，南部是秦岭，西部是高原，东部是山谷平原。分析表明，长期严重的霾天气的形成和发展在很大程度上取决于持续的南风和东风。由于地形的复杂影响，从表面到对流层中部，GZB在垂直剖面上形成了弱的收敛稳定的分层散度分布。850 hPa附近存在稳定的分层，具有接近零的垂直速度和明显的反演层的特征。在这种大气环境中，空气污染加剧，直到西北风增强。此外，山谷循环在霾的日变化中起重要作用。白天，山谷的微风消散了污染物，降低了PM 山谷循环在霾的日变化中起重要作用。白天，山谷的微风消散了污染物，降低了PM 山谷循环在霾的日变化中起重要作用。白天，山谷的微风消散了污染物，降低了PM_2.5浓度。到了晚上，山风将污染物带入盆地，PM _2.5浓度增加。这项研究表明，地形条件是造成GZB雾霾的原因，因此应努力减少该区域的排放。