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

作　　者：陈健 石春娥[2] 邓学良 程鲒 徐倩倩 孙维 CHEN Jian;SHI Chun′e;DENG Xueliang;CHENG Jie;XU Qianqian;SUN Wei(Hefei Meteorological Bureau,Hefei 230041;Anhui Institute of Meteorological Sciences,Key Laboratory of Atmospheric Science and Satellite Remote Sensing,Hefei 230031;Anhui Public Meteorological Service Center,Hefei 230031)

机构地区：[1]安徽省合肥市气象局,合肥230041 [2]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 [3]安徽省公共气象服务中心,合肥230031

出　　处：《环境科学学报》2022年第6期285-294,共10页Acta Scientiae Circumstantiae

基　　金：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)。

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PM_(2.5)、PM_(10)浓度的影响.结果表明:冬半年降水日PM_(2.5)、PM_(10)平均浓度较无降水日分别下降18.1μg·m^(-3)(23.9%)、38.2μg·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PM_(2.5)和PM_(10)浓度不降反升;当日降水量大于10 mm,位于“优”等级的PM_(2.5)和PM_(10)浓度比例分别为54%和80%,显著上升.连续降水期间PM_(2.5)、PM_(10)日均浓度中位值和均值逐日下降,降水第2日PM_(2.5)、PM_(10)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PM_(2.5)、PM_(10)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PM_(2.5)、PM_(10)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PM_(2.5)、PM_(10)平均浓度偏高.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 PM_(2.5) and PM_(10) in Hefei were analyzed using conventional statistics and synoptic methods.The results showed that the average concentrations of PM_(2.5) and PM_(10) on precipitation days decreased by 18.1μg·m^(-3) and 38.2μg·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 PM_(2.5) and PM_(10) concentrations of 28%of the samples did not decrease but increased.When the daily precipitation was above 10 mm,the percentages of PM_(2.5) and PM_(10) concentrations at the“excellent”level increased significantly,reaching 54%for PM_(2.5) and 80%for PM_(10).During the continuous precipitation period,the median and average values of the daily average concentrations of PM_(2.5) and PM_(10) decreased day by day,with the biggest decrease of the daily average concentration of PM_(2.5) and PM_(10) 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 PM_(2.5) and PM_(10) 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 PM_(2.5) and PM_(10);with the largest wind speed,the clearance effect on PM of the low-trough&cold-front type was second only to shear-line type

关 键 词：降水强度 天气型 PM_(2.5/10) 合肥 

分 类 号：X513[环境科学与工程—环境工程]