气溶胶吸湿性及其对霾形成的影响研究进展

气溶胶吸湿性与其微物理过程和化学性质密切相关,研究气溶胶吸湿性对于揭示雾霾的形成机制,提高云凝结核（CCN）模拟精度等具有重要意义。在调研国内外相关文献的基础上,总结了大气气溶胶吸湿性测量与模拟计算方法,梳理了气溶胶吸湿性与气溶胶粒子组分、粒径谱、粒子老化过程及混合态的关系。由于排放源和环境条件的不同,不同区域气溶胶吸湿性具有不同的变化特征,气溶胶吸湿性对霾形成具有重要影响,气溶胶吸湿性引起的辐射强迫越来越得到关注。通过以上分析总结,以期为未来与气溶胶吸湿性研究的相关工作提供参考借鉴。     

北京和邢台新粒子生成的差别及其对CCN活性的影响

基于2016年冬季和2017年夏季在北京、2016年夏季在邢台的三次气溶胶外场观测实验,选取三次观测期间典型的新粒子生成事件,分析其对气溶胶吸湿和云凝结核（CCN）活化特性的影响。两地分别位于华北平原北部超大城市区域和中南部工业化区域,两地不同季节新粒子形成机制不同,对应的凝结汇、生长速率以及气溶胶化学组分也不同。北京站点新粒子生成事件的发生以有机物的生成主导,而邢台站点新粒子生成事件的发生则以硫酸盐和有机物的生成共同主导。邢台站点新粒子生成过程中气溶胶吸湿性及云凝结核活化能力明显强于北京站点,此特点在核模态尺度粒子中表现尤为明显。以上结果表明,在估算新粒子生成对CCN数浓度的影响时,应充分考虑气溶胶吸湿和活化特性的差异。     

重庆冬季大气气溶胶的物理、化学特征

利用2001—2002年重庆冬季大气气溶胶粒子观测资料，分析了气溶胶粒子的数浓度、质量浓度、谱分布、化学元素组成及其与气象因子的关系。结果表明，重庆冬季大气气溶胶数浓度与我国其他大城市处于同一水平，大于0．3μm气溶胶粒子的平均数浓度为225．3个／cm^3（最大337．8个／cm^3）；冷空气入侵和降水是局地气溶胶的主要清除机制，雾的存在可以显著地改变气溶胶数浓度的一般日变化规律；PM10占TSP（Total Suspended Particles，总悬浮颗粒物）质量浓度的60％～80％；人为污染元素S、zn、As、Ph等在细粒子中富集较高。     

广州气溶胶质量谱与水溶性成分谱的年变化特征

广州气溶胶质量谱与水溶性成分谱的年变化特征吴兑，陈位超（广州热带海洋气象研究所，广州，５１００８０）近年来，我们曾在粤、桂、琼三省华南广大地区采集并分析了大气气溶胶分级样品，从气溶胶参与雨水酸化过程，吸湿性气溶胶作为凝结核的作用，以及海岸地带吸湿性粒...     

城市大气气溶胶的物理化学特性及其对人体健康的影响

根据在北京、重庆、上海等城市大气气溶胶的观测结果和气溶胶中有机化学成分的有关资料,分析城市地区大气气溶胶的浓度、尺度谱分布、日变化规律及其化学成分的谱分布特征,并与干净地区的结果作比较,进而探讨了大气气溶胶对人体健康的影响。     

石家庄地区2005年秋季污染气溶胶飞机观测资料分析

利用河北省2005年10月份的3次气溶胶飞机观测资料和宏观天气资料,综合分析石家庄地区不同天气条件下气溶胶的垂直分布和尺度谱分布特征。分析结果表明:气溶胶浓度的分布与大气环境情况密切相关。气溶胶数浓度最大值的变化范围是103~104cm-3,平均数浓度为103cm-3,粒子平均直径为0.120~0.150μm;21日近地面有霾,相对湿度为58%,近地面气溶胶浓度较17和29日略低,但粒子平均直径(0.165μm)比其余两次要大,可见相对湿度较大,大气中水汽含量较多,有利于小粒子凝结水汽,使粒子直径增大;逆温层结下,粒子在逆温层下累积,无逆温时数浓度最大值出现在近地面附近。气溶胶粒子谱呈单峰分布。     

南京冬季大气气溶胶的物理特征

根据１９９３年１１月１５日－１２月－１０日南京北部的大气气溶胶粒子的连续观测资料，分析了大气气溶胶粒子的浓度，日变化，日际变化，谱分布以及降水对大气气溶胶粒子的湿沉降清除。     

2004年北京地区秋季大气气溶胶粒子分布特征

2004年秋季在北京地区利用机载大气气溶胶粒子探头进行了大气气溶胶观测,获得了0～7 km气溶胶细粒子数浓度和尺度谱分布的垂直、水平变化特征.结果表明:北京地区上空气溶胶粒子数浓度在1 km左右高度以下的混合层内有均匀的分布,明显递减层的高度范围约在1～2 km之间,2 km以上随高度递减很小,高层气溶胶数浓度变化不大...     

边界层大气气溶胶浓度与尺度谱分布的时空变化

1980年8月初,用光学粒子计数器,在北京325米气象塔上获得了从地面至300米六层的大气气溶胶浓度与尺度谱的垂直分布。由实测浓度N_z,按公式,用最小二乘法原理确定气溶胶标高H_p。分析指出,大气气溶胶浓度和尺度谱的时间、空间变化明显。采用三参数谱分布模式描述各层的平均谱,其谱分布参数随高度而变化。     

泽当、景洪大气气溶胶粒子的物理、化学特性

利用 1 997～ 1 999年在西藏泽当、云南景洪观测地飞得到的大气气溶胶资料 ,分析了气溶胶粒子的物理化学特性 ,包括质量浓度、数浓度、光学吸收系数和化学组成 ,初步讨论了有关的影响因子 ,并同国内外其它地区的观测结果进行了比较。结果表明 ,大气气溶胶粒子在以上两地以及与其它地区之间存在明显的差异     

Visibility trends in six megacities in China 1973–2007

The particulate matter pollution has been serious in Chinese megacities due to the rapidly expanding economic and industrial developments, which has significant influences in atmospheric visibility. Visibility is a highly relevant factor indicating the level of atmospheric quality, and is inversely related to the optical extinction coefficient caused by gas and particle phases. In our study, visibility trends for six major megacities (Beijing, Chengdu, Guangzhou, Shanghai, Shenyang, and Xi'an) in China were evaluated during 1973–2007 on the basis of the National Climatic Data Center (NCDC) database using four measurement methods: the days per year of daily visibility < 10 km, the days per year of daily visibility > 19 km, the annual mean visibility, and the dry extinction coefficient. The annual and seasonal change trends of visibility for each city were analyzed by using a linear regression model. The annual mean visibilities for the six cities (Beijing, Chengdu, Guangzhou, Shanghai, Shenyang, and Xi'an) were 10.67, 8.60, 10.76, 8.59, 8.16, and 9.74 km respectively. Shenyang has experienced a significant increasing trend during the entire time series while visibilities for other five sites showed decreasing trends especially since the middle of 1990s. In the southern and midwestern regions (Chengdu, Guangzhou, Shanghai, and Xi'an), visibility was best in summer, whereas in the northern regions (Beijing and Shenyang), visibility was best in spring. Mean visibility in spring was worst at Guangzhou, while for the other five cities visibility in winter was worst, probably because of coal burning during the heating period. The general degradation of visibility in these megacities was probably due to the excess aerosol loading. Consequently, an urgent targeted reduction of aerosol pollution may be needed for the sake of better air quality in Chinese megacities.     

北京地区气溶胶粒度谱分布初步研究

本文对北京地区气溶胶数浓度及其诸分布特征进行了初步研究。重点探讨了气溶胶数浓度分布与相对湿度的关系。研究结果表明，气溶胶浓度和谱分布存在明显的日变化和逐日变化，并在很大程度上受空气相对湿度和理查森数影响。     

Comparison of Submicron Particles at a Rural and an Urban Site in the North China Plain during the December 2016 Heavy Pollution Episodes

An extensive field experiment for measurement of physical and chemical properties of aerosols was conducted at an urban site in the Chinese Academy of Meteorological Sciences (CAMS) in Beijing and at a rural site in Gucheng (GC), Hebei Province in December 2016. This paper compares the number size distribution of submicron particle matter (PM1, diameter < 1 μm) between the two sites. The results show that the mean PM1 number concentration at GC was twice that at CAMS, and the mass concentration was three times the amount at CAMS. It is found that the accumulation mode (100–850 nm) particles constituted the largest fraction of PM1 at GC, which was significantly correlated with the local coal combustion, as confirmed by a significant relationship between the accumulation mode and the absorption coefficient of soot particles. The high PM1 concentration at GC prevented the occurrence of new particle formation (NPF) events, while eight such events were observed at CAMS. During the NPF events, the mass fraction of sulfate increased significantly, indicating that sulfate played an important role in NPF. The contribution of regional transport to PM1 mass concentration was approximately 50% at both sites, same as that of the local emission. However, during the red-alert period when emission control took place, the contribution of regional transport was notably higher.     

黄土高原半干旱区典型日吸收性气溶胶综合观测分析

利用兰州大学半干旱气候与环境观测站的太阳光度计、激光雷达、微波辐射计综合观测资料,结合辐射传输模式分析了该地区秋季典型日2012年9月3~4日、21日和28日气溶胶物理特性、垂直分布特征,及其与气象条件的关系。研究时期的气溶胶主要为局地沙尘与人为污染混合气溶胶,吸收性明显,尺度较小。其中,4日西北风增强,远距离传输沙尘气溶胶,气溶胶光学厚度最大,粒子尺度明显增大。尝试利用灰色关联度法确定参考高度,分别为7.41 km、8.47 km、7.13 km和7.66 km,反演气溶胶消光系数,由此积分得到的光学厚度与太阳光度计观测值相关性可达0.975,反演效果较好。研究时期气溶胶的抬升主要受白天热力湍流作用,边界层发展,气溶胶向上传输,每日12时（当地时间,下同）至14时传输至最大高度,气溶胶抬升的高度对应大气加热率的高值区,低层加热率可达1 K d-1。气溶胶在大气层顶和地面造成负辐射强迫,分别为-12.707 W m-2、-25.398 W m-2,大气中表现为正辐射强迫,为12.692 W m-2,大气层顶的辐射强迫对气溶胶的物理特性最为敏感,当气溶胶吸收性明显时,大气层顶的瞬时辐射强迫会出现正值。     

Aerosol spectra and new particle formation observed in various seasons in Nanjing

The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations exhibited distinct seasonal variations, implying the relations of particle sizes and their sources and sinks. The number concentrations of particles in the nuclei mode （10-30 nm）, Aitken mode （30-100 nm）, accumulation mode （100 -1000 nm） and coarse mode （〉1μm） varied in the order of summer 〉 spring 〉 autumn, summer 〉 autumn 〉 spring, autumn 〉 summer 〉 spring, and spring 〉 autumn 〉summer, re- spectively. The diurnal variation of total aerosol number concentrations showed three peaks in all observed periods, which corresponded to two rush hours and the photochemistry period at noon. In general, the NPF in summer occurred under the conditions of east winds and dominant air masses originating from marine areas with high relative humidity （50%-70%） and strong solar radiations （400 -700 W m-2）. In spring, the NPF were generally accompanied by low relative humidity （14%-30%） and strong solar radiations （400-600 W m-2）. The new particle growth rates （GR） were higher in the summertime in the range of 10- 16 nm h-1. In spring, the GR were 6.8-8.3 nm h-1. Under polluted air conditions, NPF events were seldom captured in autumn in Nanjing. During NPF periods, positive correlations between 10- 30 nm particles and 03 were detected, particularly in spring, indicating that NPF can be attributed to photochemical reactions.     

Vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai

A comparative study on the vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai was conducted based on the data obtained from a micro pulse lidar.There was a distinct difference in layer thickness and extinction coefficient under the two types of weather conditions.Aerosols were concentrated below 1 km and the aerosol extinction coefficients ranged from 0.25 to 1.50km^-1 on haze days.In contrast,aerosols with smaller extinction coefficients(0.20 0.35 km^-1) accumulated mainly from the surface to 2 km on floating dust days.The seasonal variations of extinction and aerosol optical depth（AOD） for both haze and floating dust cases were similar greatest in winter,smaller in spring,and smallest in autumn.More than 85%of the aerosols appeared in the atmosphere below 1 km during severe haze and floating dust weather.The diurnal variation of the extinction coefficient of haze exhibited a bimodal shape with two peaks in the morning or at noon,and at nightfall,respectively.The aerosol extinction coefficient gradually increased throughout the day during floating dust weather.Case studies showed that haze aerosols were generated from the surface and then lifted up,but floating dust aerosols were transported vertically from higher altitude to the surface.The AOD during floating dust weather was higher than that during haze.The boundary layer was more stable during haze than during floating dust weather.     

霾期间上海低层气溶胶微物理属性与地面相对湿度分析

用2007年1月至2010年11月美国国家航空航天局(NASA)的CALIPSO星载激光雷达资料,通过532 nm总后向散射系数、体积退偏比和色比,分析了上海地区霾期间低层0~2 km高度气溶胶微物理属性与地面相对湿度的关系。结果表明,当地面相对湿度为65%~80%时,后向散射系数在0~0.001 km-1·sr-1范围内出现的频率最大;当地面相对湿度为50%~65%时,后向散射系数大于0.001 km-1·sr-1的频率最大;低层大气中聚集的主要是规则气溶胶粒子,当地面相对湿度为65%~80%时,气溶胶粒子最为规则,其次为80%~95%的地面相对湿度。当地面相对湿度为50%~65%时,不规则气溶胶粒子所占比重较大;霾期间,低层大气中细粒子气溶胶均占主导地位,但随着地面相对湿度的增大,气溶胶粒子粒径逐渐增大。在地面相对湿度为80%~95%时,大颗粒气溶胶相对较多。     

Observations of Aerosol Optical Properties in the Beijing Urban Area in Summer

To investigate aerosol optical properties in the Beijing metropolitan area,aerosol absorption coefficient(Ab) ,scattering coefficient(Sc) ,and fine particulate matter(PM2.5) were measured in the Beijing urban area from 20 May to 30 August 2009.The average Ab,Sc,single scattering albedo(SSA) ,and PM2.5 concentration were 58.0±39.5 M m-1,343.5±353.7 M m-1,0.80±0.10 and 63.6±50.0-g m-3,respectively,during the observation period.Ab,Sc,and SSA all showed single peak diurnal variations,with their maximum values being measured at 0500,1000,and 1300 local time,respectively.Ab and Sc had a strong positive correlation with PM2.5,and Ab,Sc,and PM2.5 all had positive correlations with relative humidity and negative correlations with wind speed.