塔城地区南部冬季能见度特征及其影响因子分析

Analysis of Winter Visibility Characteristics and Its Influencing Factors in the South of Tacheng Area

摘要: 利用塔城地区南部乌苏、沙湾2015年~2020年国家气象观测站地面观测资料和环境监测站大气污染监测资料，分析塔城地区南部大气能见度与污染要素和气象因子之间的关系。结果表明：塔城地区南部2015年至2019年冬季平均能见度为5310 m；月均能见度1月 < 12月 < 2月；能见度的日变化呈现明显的双峰型特征，冬季清晨至上午、傍晚至凌晨能见度相对较低；小于800米的低能见度出现频次在09时至14时较高，而小于200米的低能见度在03时至11时出现频次较高；塔城地区南部冬季大气能见度与PM₁₀和PM_2.5呈负相关关系，与NO_X，O₃，SO₂相关性不明显；与相对湿度呈显著的负相关关系，与气温呈正相关关系，而与气压、风速相关性不显著；冬季出现大雾日数占全年74%，大雾是影响能见度的主要天气，当EC细网格低层相对湿度925 hPa日均值 > 90%时，出现大雾天气的可能性较大；利用污染要素和气象因子建立线性统计回归模型，发现利用PM_2.5、相对湿度建立的拟合公式最优，能较好地模拟塔城地区南部冬季大气能见度变化。

Abstract: Based on the ground observation data of national meteorological observation stations and air pollution monitoring data of environmental monitoring stations in Wusu and Shawan in the south of Tacheng area from 2015 to 2020, the relationship between atmospheric visibility and pollution elements and meteorological factors in the south of Tacheng area is analyzed. The results show that the average visibility in the south of Tacheng area in winter from 2015 to 2019 is 5310 m; Monthly average visibility: January < December < February; The diurnal variation of visibility shows obvious bimodal characteristics. In winter, the visibility is relatively low from early morning to morning and from evening to early morning; The frequency of low visibility less than 800 meters is higher from 09:00 to 14:00, while the frequency of low visibility less than 200 meters is higher from 03:00 to 11:00; There is a negative correlation between atmospheric visibility and PM₁₀ and PM_2.5 in the south of Tacheng area in winter, but there is no obvious correlation with NO_x, O₃ and SO₂; It has a significant negative correlation with relative humidity, a positive correlation with air temperature, but not with air pressure and wind speed; The number of foggy days in winter accounts for 74% of the whole year. Foggy weather is the main weather affecting visibility. When the daily mean relative humidity in the lower layer of EC 925 hPa is >90%, it is more likely to have foggy weather; The linear statistical regression model is established by using pollution factors and meteorological factors. It is found that the fitting formula established by PM_2.5 and relative humidity is the best, which can better simulate the change of atmospheric visibility in southern Tacheng area in winter.