CAJ | 학술논문

针对无锡地区2013年8月13日至31日期间的晴朗、降雨、污染过程,利用地基遥感设备大气颗粒物监测激光雷达对气溶胶光学特性的时空演变特征进行监测.结果表明晴朗天气下污染物早晚分布较少、中午集聚较多的特点,并且午间污染物的扩散高度可以达到1.5 km 以上.晴朗天气下气流的水平、垂直运动增强有利于污染的扩散,这也是污染程度较轻和能见度超过20 km 的重要原因；降雨过程中,雨云层分布高度在500 m 以下,雨云中的水滴产生的消光系数大于2 km-1,能见度不足10 km,降雨过程中空气对流增强,风速增大,加上颗粒物的湿沉降作用减轻污染程度；污染时段,由于静稳天气,使得污染物扩散不利,颗粒物主要集中在近地面1 km 以内,颗粒物产生的消光系数较长时段超过0.5 km-1.激光雷达的探测结果显示,8月30日外来污染物的输送和局地污染物的复合使得污染程度加重.通过后向轨迹模式分析发现,该污染团可能来自站点的西北方向.近地面 PM2.5的质量浓度在晴天和降雨过程中均不超过50μg·m-3,但是在污染过程中,PM2.5峰值接近160μg·m-3.近地面碳黑浓度的变化趋势 PM2.5一致,尤其在污染过程中,碳黑的质量浓度达到9μg·m-3.结合近地面观测与颗粒物激光雷达的地基遥感监测结果,能够对无锡地区颗粒物的垂直分布进行初步解析.
침대무석지구2013년8월13일지31일기간적청랑、강우、오염과정,이용지기요감설비대기과립물감측격광뢰체대기용효광학특성적시공연변특정진행감측.결과표명청랑천기하오염물조만분포교소、중오집취교다적특점,병차오간오염물적확산고도가이체도1.5 km 이상.청랑천기하기류적수평、수직운동증강유리우오염적확산,저야시오염정도교경화능견도초과20 km 적중요원인；강우과정중,우운층분포고도재500 m 이하,우운중적수적산생적소광계수대우2 km-1,능견도불족10 km,강우과정중공기대류증강,풍속증대,가상과립물적습침강작용감경오염정도；오염시단,유우정은천기,사득오염물확산불리,과립물주요집중재근지면1 km 이내,과립물산생적소광계수교장시단초과0.5 km-1.격광뢰체적탐측결과현시,8월30일외래오염물적수송화국지오염물적복합사득오염정도가중.통과후향궤적모식분석발현,해오염단가능래자참점적서북방향.근지면 PM2.5적질량농도재청천화강우과정중균불초과50μg·m-3,단시재오염과정중,PM2.5봉치접근160μg·m-3.근지면탄흑농도적변화추세 PM2.5일치,우기재오염과정중,탄흑적질량농도체도9μg·m-3.결합근지면관측여과립물격광뢰체적지기요감감측결과,능구대무석지구과립물적수직분포진행초보해석.
A continuous observation to study the vertical distribution of particulate matter has been conducted at Wuxi city during August 13 th to 31 st 2013.In this experiment,the ground-based particulate LiDAR(Light Detection and Ranging)system was used for the retrieval the aerosol optical properties (extinction coefficients,depolarization coefficients)varying along with height in clear days,rainy days and polluted days,e.g.haze pollution.The results showed that particulate matter accumulated rather rare in the early morning and in the evening for clear days,while it was rich at noon.The top of particulate matter layer extended to 1.5 km due to the strong convection of airflow in vertical and horizontal direction.In this case,the visibility range reached over 20 km.LiDAR detection also revealed that the rainy clouds covered at 500 m off ground level in rainy interval.The extinction coefficients exceeded 2 km-1 due to the large volume of water drops.We found that the visibility was no more than 10 km in raining duration.The fast airflow movement and strong wind combining with wet deposition of atmosphere particles may contribute for the less pollution in rainy days.In polluted episodes,the calm condition was not good for particulate matter dispersing in vertical and horizontal level;therefore,most of the aerosol was trapped in 1 km from ground level.The maximum in the extinction coefficients profile of aerosol always exceed 0.5 km-1 from LiDAR detection.A polluted air mass transferred over-boundary made local air quality worse on August 30 th .Model simulation results from HYSPLIT estimated the possible origin of this air mass was from the Northwest of monitoring station.PM2.5 con-centration was below 50 μg·m-3 in clear days and rainy days,but the peak value of PM2.5 in haze pollution was closed to 1 60 μg·m-3 .A better consistence between PM2.5 and black carbon(BC)has been shown in polluted days than the other two cases.The climax of BC was approaching 9 μg·m-3 in polluted period.The exact observations of PM2.5 and BC perfectly supported the detection of LiDAR and together constructed a whole picture of particulate matter vertical distribution for Wuxi city.