研究报告
陈健,石春娥,邓学良,程鲒,徐倩倩,孙维.合肥冬半年降水及所处天气型对大气颗粒物浓度的影响[J].环境科学学报,2022,42(6):285-294
合肥冬半年降水及所处天气型对大气颗粒物浓度的影响
- Influence of winter precipitation and synoptic patterns on the concentration of atmospheric particles in Hefei
- 基金项目：国家自然科学基金（ No.41875171 ）； 安徽省重点研究和开发计划（ No.1804a0802215 ）； 合肥市关键技术研发项目（ No.J2020J07 ）
- 作者
- 单位
- 陈健
- 安徽省合肥市气象局，合肥 230041
- 石春娥
- 安徽省气象科学研究所，安徽省大气科学与卫星遥感重点实验室，合肥 230031
- 邓学良
- 安徽省合肥市气象局，合肥 230041
- 程鲒
- 安徽省合肥市气象局，合肥 230041
- 徐倩倩
- 安徽省合肥市气象局，合肥 230041
- 孙维
- 安徽省公共气象服务中心，合肥 230031
- 摘要：利用合肥市2015—2017年冬半年环境监测站和自动气象站数据，以及高空、地面天气图资料，运用常规统计和天气学方法分析了降水强度及不同降水天气系统对PM2.5、PM10浓度的影响.结果表明：冬半年降水日PM2.5、PM10平均浓度较无降水日分别下降18.1 μg·m-3（23.9%）、38.2 μg·m-3（37.8%）；小于5 mm的日降水量对颗粒物清除效果不明显，且有28%样本PM2.5和PM10浓度不降反升； 当日降水量大于10 mm，位于“优”等级的PM2.5和PM10浓度比例分别为54%和80%， 显著上升.连续降水期间PM2.5、PM10日均浓度中位值和均值逐日下降， 降水第2日PM2.5、PM10日均浓度降幅最大.合肥冬半年降水天气系统可以分为切变线Ⅰ型、切变线Ⅱ型、低槽冷锋型和西风槽型，其中切变线Ⅰ型对应的地面风速最大、日降水量最大，对颗粒物的清除效果最为明显，对应着最低的PM2.5、PM10浓度；而西风槽型和切变线Ⅱ型由于风速和日降水量均低，对颗粒物清除效果差，在4类降水型中西风槽型对应的PM2.5、PM10平均浓度最高；低槽冷锋型风速最大，对颗粒物的清除能力仅次于切变线Ⅰ型，但由于日降水量不大，对应的PM2.5、PM10平均浓度偏高.
- Abstract：Based on the data of environmental monitoring stations and automatic weather stations， together with the surface and high-level synoptic maps in Jan-Mar and Oct-Dec from 2015 to 2017， the influences of precipitation intensity and different precipitation synoptic patterns on the concentrations of PM2.5 and PM10 in Hefei were analyzed using conventional statistics and synoptic methods. The results showed that the average concentrations of PM2.5 and PM10 on precipitation days decreased by 18.1 μg·m-3 and 38.2 μg·m-3 respectively comparing with those on no precipitation days. The daily precipitation less than 5 mm had no obvious effect on the clearance of particulate matters， and the PM2.5 and PM10 concentrations of 28% of the samples did not decrease but increased. When the daily precipitation was above 10 mm， the percentages of PM2.5 and PM10 concentrations at the “excellent” level increased significantly， reaching 54% for PM2.5 and 80% for PM10. During the continuous precipitation period， the median and average values of the daily average concentrations of PM2.5 and PM10 decreased day by day， with the biggest decrease of the daily average concentration of PM2.5 and PM10 on the second precipitation day. The precipitation weather system of Hefei in Jan-Mar and Oct-Dec can be divided into four types， those are， shear-line type I， shear-line type II， low-trough & cold-front type and westerly-trough type.Among the four weather systems， the shear-line type I corresponded to the lowest average concentrations of PM2.5 and PM10 due to the maximum surface wind speed and daily precipitation， showing the most obvious effect on the clearance of particulates； due to low wind speed and daily precipitation， the westerly-trough type and shear-line type II had poor clearance effects on particulate matter， corresponding to the highest average concentration of PM2.5 and PM10； with the largest wind speed， the clearance effect on PM of the low-trough & cold-front type was second only to shear-line type I； however， due to the small daily precipitation， the corresponding average concentrations of PM2.5 and PM10 were still large.
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