2008年北京奥运会期间大气气溶胶物理特征分析

应用MODIS卫星的气溶胶产品资料和地面的光学粒子计数器的资料,对比分析了北京地区2006、2007、2008年7～9月的气溶胶光学厚度、细粒子光学厚度、Angstrom指数、气溶胶粒子数浓度谱及体积谱,发现2008年北京奥运会期间(7月20日～9月20日)的气溶胶光学厚度比2006、2007年同期明显降低,气溶胶细模态光学厚度占总光学厚度的比上升,Angstrom指数上升,气溶胶细粒子数浓度没有明显相对变化,而粗粒子数浓度则减少约50%.利用大气标高,将MODIS反演的气溶胶柱的质量浓度转化为地面气溶胶质量浓度.用粒子计数器得到的体积谱,在假定气溶胶粒子密度的情况下,计算出其质量浓度.将这两种方法得到的气溶胶质量浓度与国家环境保护部公布的空气质量指数换算得到的可吸入颗粒物(PM10)质量浓度进行比较.结果表明:北京奥运期间空气质量总体达到了国家二级空气质量标准;与2006、2007年同期相比,2008年气溶胶PM10质量浓度明显下降,而这主要是由气溶胶粗粒子的减少引起的.     

生物质燃烧输送对青藏高原气溶胶光学辐射特性的影响研究

利用青藏高原拉萨(Lhasa)和珠峰(QOMS_CAS)站点地基CE 318太阳光度计观测数据，研究了2012年4月2日至4月5日一次生物质燃烧输送对青藏高原气溶胶光学和辐射特性的影响；并结合卫星遥感产品以及后向轨迹模式分析了本次生物质燃烧输送的可能来源。结果表明：本次气溶胶污染期间Lhasa和QOMS_CAS站点的主要气溶胶类型变为生物质燃烧气溶胶，气溶胶粒子的消光性增大(气溶胶光学厚度(AOD)增大，Lhasa和QOMS_CAS站点AOD最大值分别为0.4和0.29)，尺度减小(消光波长指数(EAE)>1.5)，吸收性增大(吸收波长指数(AAE)>1.3)，细模态粒子体积浓度增大，而细模态粒子峰值半径减小。气溶胶辐射强迫表明此次输送过程使得Lhasa和QOMS_CAS站点的气溶胶对大气顶和地表的降温作用增强，对大气的增温作用也增强。生物质燃烧输送的可能来源为南亚的印度东北部，尼泊尔与不丹地区。     

Weather effects on the aerosol characteristics in the surface layer of the atmosphere

On the basis of 14-year (1994–2007) series of the semi-annual (January to June) measurements of the atmospheric aerosol microstructure in Dolgoprudny, Moscow region, effects are analyzed of pressure, wind speed, precipitation, and surface temperature inversions on the aerosol particle concentration. It is shown that the weather parameters affect concentration of the particles within a certain range of sizes (0.1 to 1 μm). Concentration of the smaller particles practically does not depend on the weather conditions. The weather effects on large (> 1 μm) particle concentration are not detected due to too high variability of the latter. From three the most available weather parameters (pressure, wind, daily precipitation amount), the observed weather conditions are classified, and for the detected types of weather, typical concentrations are determined of the aerosol particles of different sizes, which allow approximately estimating, from the standard weather data, the aerosol pollution under different meteorological situations.     

Influence of natural and anthropogenic activities on UV Index variations – a study over tropical urban region using ground based observations and satellite data

Measurements of total ozone column and solar UV radiation under different atmospheric conditions are needed to define variations of both UV and ozone and to study the impact of ozone depletion at the Earth’s surface. In this study, spectral and broadband measurements of UV-B irradiance were obtained along with total ozone observations and aerosol optical depth measurements in the tropical urban region of Hyderabad, south India. We specifically used an Ultra-Violet Multifilter Rotating Shadow band Radiometer (UVMFR-SR), to measure UV irradiance in time and space. To assess the aerosol and O₃ effects on ground-reaching UV irradiance, we used measurements from a Microtops II sun photometer in addition to the Tropospheric Ultraviolet Visible radiation (TUV) model. We also assessed the Defense Meteorological Satellite Program – Operational Line Scanner (DMSP-OLS) night time satellite data for inferring biomass burning fires during the study period. Results clearly suggested a negative correlation between the DMSP-OLS satellite derived fire count data and UVMFR-SR data suggesting that aerosols from biomass burning are directly attenuating UV irradiance in the study region. Also, correlation analysis between UV index and ozone measurements from sun photometer and TOMS-Ozone Mapping Instrument (OMI) indicated a clear decrease in ground reaching UV-B irradiance during higher ozone conditions. The higher levels are attributed to photochemical production of O₃ during the oxidation of trace gases emitted from biomass burning. Results also suggested a relatively high attenuation in UV irradiance (~6% higher) from smoke particles than dust. We also found a relatively good agreement between the modeled (TUV) and measured UV irradiance spectra for different atmospheric conditions. Our results highlight the factors affecting UV irradiance in a tropical urban environment, south India.     

Cloud condensation nuclei from biomass burning during the Amazonian dry-to-wet transition season

Aircraft measurements of cloud condensation nuclei (CCN) during the Large-Scale Biosphere–Atmosphere Experiment in Amazonia (LBA) were conducted over the Southwestern Amazon region in September–October 2002, to emphasize the dry-to-wet transition season. The CCN concentrations were measured for values within the range 0.1–1.0% of supersaturation. The CCN concentration inside the boundary layer revealed a general decreasing trend during the transition from the end of the dry season to the onset of the wet season. Clean and polluted areas showed large differences. The differences were not so strong at high levels in the troposphere and there was evidence supporting the semi-direct aerosol effect in suppressing convection through the evaporation of clouds by aerosol absorption. The measurements also showed a diurnal cycle following biomass burning activity. Although biomass burning was the most important source of CCN, it was seen as a source of relatively efficient CCN, since the increase was significant only at high supersaturations.     

南京地区气溶胶谱分布的湿度相关性分析和等效复折射率预测

通过实验收集大气颗粒物，对南京地区大气气溶胶谱分布进行了描述，对气溶胶分布与相对湿度的相关性进行了探讨。建立了南京地区7—11月气溶胶化学组分的月平均模型，得出气溶胶等效复折射率的预测方法。结果表明：南京地区的大气气溶胶颗粒物，峰值粒径在80~100 nm范围，属于典型的城市型气溶胶。数浓度与相对湿度的相关性与季节和粒径大小有关，在6—9月，相对湿度与细粒子数浓度呈负相关，与粗粒子呈正相关，在10—11月相反，且易受极端天气影响。建立的干气溶胶等效复折射率月平均模型，结合湿度修正模型得到某一日的复折射率，与AERONET站点数据进行了对比，结果较为一致，误差范围在0~0.03。     

Atmospheric aerosol characterization in 2010 anomalous summer season in the Moscow region

Daily measurements of atmospheric aerosol characteristics were carried out in Dolgoprudny (Moscow region) in June–August 2010. The particle concentrations at 11 size gradations within the range of 0.01–10 μm and the concentrations of cloud condensation nuclei active at water vapor supersaturation of 0.2–1% were determined. It is shown that the long anticyclonic conditions and the burning of forests and peat bogs resulted in the increase in total aerosol concentration in surface air by more than 1.5 times and in concentrations of particles with the diameter of 0.1–1 μm and > 1 μm by 5 and 10 times, respectively. The fire smoke mainly consisted of the particles with the size of 0.1–3 μm. The particles with the size of more than 5 μm were not observed. The recurrent visibility decrease up to hundreds of meters was caused by the increase in the concentration of particles with the diameter of more than 0.32μm in the air. During the smoke blanketing, the concentration of active condensation nuclei in aerosol increased almost by 20 times that created an opportunity for watering of aerosol particles and formation of the acid smog.     

秸秆燃烧对北京秋季气溶胶浓度和短波辐射影响的模拟研究

利用地面细颗粒物（PM2.5）浓度和气象常规观测资料、地基 AERONET观测资料、GFED生物质燃烧排放清单和大气化学—天气耦合模式WRF-Chem,模拟研究了华北地区2014年10月气象要素和大气污染物的时空演变,重点关注北京10月7～11日的一次重霾事件及其天气形势、边界层气象特征、输送路径、PM2.5及其化学成分浓度变化等特征,以及秸秆燃烧对华北和北京地区细颗粒物浓度和地面短波辐射的影响。与观测资料的对比结果显示,模式可以很好地模拟北京地区地面气象要素和PM2.5质量浓度,考虑秸秆燃烧排放源可以明显改进北京PM2.5浓度模拟的准确性,但在重度污染情况下,模式总体上低估气溶胶光学厚度和高估地面短波辐射。10月7～11日北京地区重霾事件主要是不利气象条件下人为污染物累积和区域输送造成,也受到华北地区南部秸秆燃烧的影响。河南北部、河北南部和山东西部大面积秸秆燃烧释放的气态污染物和颗粒物在南风的作用下输送至北京,秸秆燃烧对北京地区地面PM2.5、有机碳（OC）、硝酸盐、铵盐、硫酸盐和黑碳（BC）的平均贡献率分别为24.6%、36.8%、23.2%、22.6%、7.1%和19.8%,秸秆燃烧产生的气溶胶可以导致北京地面平均短波辐射最大减小超过20 W m－2,约占总气溶胶导致地表短波辐射变化的24%。     

Influence of South Asian Biomass Burning on Ozone and Aerosol Concentrations Over the Tibetan Plateau

In this work, the influence of South Asian biomass burning emissions on O₃ and PM_2.5 concentrations over the Tibetan Plateau (TP) is investigated by using the regional climate chemistry transport model WRF-Chem. The simulation is validated by comparing meteorological fields and pollutant concentrations against in situ observations and gridded datasets, providing a clear perspective on the spatiotemporal variations of O₃ and PM_2.5 concentrations across the Indian subcontinent, including the Tibetan Plateau. Further sensitivity simulations and analyses show that emissions from South Asian biomass burning mainly affect local O₃ concentrations. For example, contribution ratios were up to 20% in the Indo-Gangetic Plain during the pre-monsoon season but below 1% over the TP throughout the year 2016. In contrast, South Asian biomass burning emissions contributed more than 60% of PM_2.5 concentration over the TP during the pre-monsoon season via significant contribution of primary PM_2.5 components (black carbon and organic carbon) in western India that were lofted to the TP by westerly winds. Therefore, it is suggested that cutting emissions from South Asian biomass burning is necessary to alleviate aerosol pollution over the TP, especially during the pre-monsoon season.     

Greenhouse-gas versus aerosol forcing and African climate response

There are many indicators that human activity may change climate conditions all around the globe through emissions of greenhouse gases. In addition, aerosol particles are emitted from various natural and anthropogenic sources. One important source of aerosols arises from biomass burning, particularly in low latitudes where shifting cultivation and land degradation lead to enhanced aerosol burden. In this study the counteracting effects of greenhouse gases and aerosols on African climate are compared using climate model experiments with fully interactive aerosols from different sources. The consideration of aerosol emissions induces a remarkable decrease in short-wave solar irradiation near the surface, especially in winter and autumn in tropical West Africa and the Congo Basin where biomass burning is mainly prevailing. This directly leads to a modification of the surface energy budget with reduced sensible heat fluxes. As a consequence, temperature decreases, compensating the strong warming signal due to enhanced trace gas concentrations. While precipitation in tropical Africa is less sensitive to the greenhouse warming, it tends to decrease, if the effect of aerosols from biomass burning is taken into account. This is partly due to the local impact of enhanced aerosol burden and partly to modifications of the large-scale monsoon circulation in the lower troposphere, usually lagging behind the season with maximum aerosol emissions. In the model equilibrium experiments, the greenhouse gas impact on temperature stands out from internal variability at various time scales from daily to decadaland the same holds for precipitation under the additional aerosol forcing. Greenhouse gases and aerosols exhibit an opposite effect on daily temperature extremes, resulting in an compensation of the individual responses under the combined forcing. In terms of precipitation, daily extreme events tend to be reduced under aerosol forcing, particularly over the tropical Atlantic and the Congo basin. These results suggest that the simulation of the multiple aerosol effects from anthropogenic sources represents an important factor in tropical climate change, hence, requiring more attention in climate modelling attempts.     

在线连续流量扩散云室对华北冬季大气冰核的观测分析

利用国内首台在线连续流量扩散云室,2017年冬季在华北地区高山站开展了大气冰核观测;结合常规气象要素、降水滴谱、气溶胶观测,分析了大气冰核数浓度特征,并对冰核活化参数化方法以及降雪对冰核的影响进行了研究。结果表明:（1）大气冰核在不同时间的浓度差异较大,?20°C时数浓度变化范围为2.50～76.8 L?1,平均值为18.347 L?1;（2）大气冰核浓度随活化温度降低呈指数增加趋势,随过饱和度增加呈指数增加,凝华核化所占比例约为18.64%;（3）大气冰核与粒径大于0.5 μm的气溶胶数浓度的关系可用参数化表示,相关性大于仅基于活化温度建立的参数化公式;（4）降雪过程大气冰核具有先增加后减少的特征。降雪开始后大气冰核数浓度增加,降雪后期系统过境伴随的大风,对气溶胶的清洗作用明显,大气冰核随之减少。本研究为在线连续流量扩散云室类型的冰核观测仪在国内首次使用,所建立的冰核参数化公式有助于华北地区冬季地形云及其降水的微物理特征研究,同时在云模式的发展和人工影响天气研究中也有重要的参考意义。     

Effects of the city of Moscow on the atmospheric aerosol characteristics in the environs

Absract  On the data of 13-year (1994–2006) measurements, during January to June, of the atmospheric aerosol characteristics in Dolgoprudny, Moscow region, effects of the city of Moscow on aerosol contamination of the surface air is analyzed. A relative increase is estimated of concentrations of particles of various sizes within the diameter range of 0.01 to 10 μm under conditions of airflow from the city of Moscow, along with changes in concentrations of cloud condensation nuclei and ice nuclei in the air. It is shown that percentage of the aerosol particles from Moscow in the total aerosol concentration within certain size ranges reaches 30% in winter months and 45% in summer ones. The aerosol transported from the city contains a significant amount of hygroscopic particles. The cloud nuclei concentration in June increases by a factor of 2 in the cases of airflow from the city. Original Russian Text ? N.O. Plaude, E.A. Stulov, N.A. Monakhova, M.V. Vychuzhanina, E.V. Sosnikova, N.P. Grishina, 2007, published in Meteorologiya i Gidrologiya, 2007, No. 12, pp. 35–43.     

Characteristics of atmospheric aerosol during the anomalous fall of 2005 in the Moscow region

Results are presented of measurements of total concentration and size spectrum of aerosol particles, of ice nuclei, and cloud condensation nuclei concentrations, as obtained during an anomalously arid period in September and October 2005 in the town of Dolgoprudny, Moscow oblast. It is shown that a two-month period of anticyclonic weather, associated with peat fires, caused a 1.5-time increase in the mean number concentration of aerosol at the site. Effects of accumulation of the industrial aerosol from Moscow and of peat bog burning products are different on fractions of particles of different sizes and on cloud-active nuclei. The smoke particles increased concentrations of almost all sizes from 0.042 to 10 μm; urban aerosol makes the greater part of concentration of particles in the middle subm-icron range and causes a significant increase in the concentration of cloud condensation nuclei.     

CALIOP对一次秸秆焚烧后气溶胶光学特性的探测分析

采用星载激光雷达(Cloud - Aerosol LIdar with Orthogonal Polarization,CALIOP)资料研究了2008年6月2日华东秸秆焚烧排放气溶胶的光学特性,并与2006～2008年统计结果进行了对比.结果表明:1)CALIOP能够有效探测到气溶胶层,探测结果符合生物质燃烧气溶胶的...     

Origins of atmospheric particulate matter over the North Sea and the Atlantic Ocean

During the ANT VII/1 cruise of the RV Polarstern from Bremerhaven (Germany) to Rio Grande do Sul (Brazil), atmospheric particulate matter was collected by bulk filtration with a time step of 36 hours. Elemental analyses were performed in order to determine atmospheric aerosol concentrations of Al, Si, P, S, K, Ca, Ti, Mn, Fe, and Zn over the North Sea, the Channel, and the North and South Atlantic. The slight and continuous moving in latitude, associated with the large variability in concentration levels and chemical composition, allow us to point out the relative influence of the major sources of particulate matter: desert soil-dust in the tropical North Atlantic, anthropogenic emissions in the North Sea and the Channel, and biomass burning and continental biogenic activity in the tropical South Atlantic.     

Fine mode aerosol chemistry over a tropical urban atmosphere: characterization of ionic and carbonaceous species

An extensive aerosol sampling program was conducted during January-December 2006 over Kolkata (22o33?? N and 88o20?? E), a mega-city in eastern India in order to understand the sources, distributions and properties of atmospheric fine mode aerosol (PM_2.5). The primary focus of this study is to determine the relative contribution of natural and anthropogenic as well as local and transported components to the total fine mode aerosol loading and their seasonal distributions over the metropolis. The average concentrations of fine mode aerosol was found to be 71.2?±?25.2???gm^-3 varying between 34.5???gm^-3 in monsoon and 112.6???gm^-3 in winter. The formation pathways of major secondary aerosol components like nitrate and sulphate in different seasons are discussed. A long range transport of dust aerosol from arid and semi-arid regions of western India and beyond was observed during pre-monsoon which significantly enriched the total aerosol concentration. Vehicular emissions, biomass burning and transported dust particles were the major sources of PM_2.5 from local and continental regions whereas sea-salt aerosol was the major source of PM_2.5 from marine source regions.     

Characterization of aerosol optical depth, aerosol mass concentration, UV irradiance and black carbon aerosols over Indo-Gangetic plains, India, during fog period

Every year during winter months (December?CJanuary) fog formation over Indo-Gangetic plains (IGP) of Indian region is believed to create numerous hazards. The present study addresses variations in aerosol optical properties, aerosol mass concentration and their impact on solar irradiance for pre-during-post fog conditions of December 2004 over IGP, India. Continuous measurements on aerosol optical depth (AOD), total aerosol mass concentration, black carbon (BC) aerosols, UV_ery and UVA were carried out for pre, during and post fog periods over study site of Allahabad, India, during December 2004 as a part of Aerosol Land Campaign-II conducted by Indian Space Research Organization (ISRO). High aerosol mass concentrations were observed during fog and post-fog periods. Accumulation mode particle loading was found to be high during pre-fog period and coarse mode particle loading was observed to be high during fog and post-fog periods. Considerable reduction in UV_ery and UVA irradiance was observed during fog period compared with pre and post-fog periods. Analysis of NOAA-HYSPLIT model runs suggested that enhanced biomass burning episodes down-wind to the study area increased the concentration of AOD and BC.     

空气污染与气候变化

近50年来,全球气候变化主要由大气温室气体浓度的日益增加引起,而空气污染主要由悬浮于空气中的大气气溶胶粒子造成,它们都主要由矿物燃料的燃烧排放形成.近年的研究表明,大气气溶胶粒子也具有气候效应:一是通过散射和吸收太阳光,减少到达地面的太阳辐射而具有降冷作用,可抵消一部分由温室气体造成的变暖作用;二是可以作为云中凝结核改变云微物理过程和降水性质,改变大气的水循环.大气气溶胶对于经济社会的许多方面,如农业、水资源、人体健康、城市化等也表现出重要的影响.由于空气污染和气候变化在很大程度上有共同的原因,即主要都是由矿物燃料燃烧的排放造成,因而减轻和控制空气污染与减少温室气体排放保护气候在行动上应是一致的.为了从经济上得到最大的节约和获得双赢的效果,应该采取协同应对空气污染和气候变化的减排战略,即应该采取统一的而不是分离的科学研究和应对战略.     

Aerosol physical characteristics at Bhubaneswar, East coast of India

Physical characterization of atmospheric aerosols was carried out using various equipments like Grimm's spectrophotometer, Aetholometer and Microtops-II at Bhubaneswar, a coastal city in the east coast of India. Meteorological parameters were recorded on-line with an automatic weather station, which showed weather relatively free from extreme events with high humidity during the period. The pre-monsoon months showed an increase in aerosol mass in the higher size ranges. The black carbon (BC) showed maximum values during winter which may be due to various anthropogenic activities like biomass burning and forest fire as well as dry conditions conducive to transport from far off places. The α values representing aerosol size distribution and β values showing the total aerosol concentration in vertical air column rose simultaneously in pre-monsoon months to attain maximum values during February–March 2008. The AOD was also correlated with PM-10 and BC concentrations.     

2009年石家庄地区不同天气条件下大气气溶胶分布特征

利用2009年石家庄地区的4次机载PMS探测资料,对不同天气条件下大气气溶胶的数浓度、平均直径垂直分布和谱分布及一次晴天条件下的水平分布进行分析。结果表明：PCASP 探头探测的0.1-3.0 μm气溶胶粒子最大数浓度的量级为102-104 cm-3之间,平均值量级为102-103 cm-3之间,平均直径最大值介于0.225-0.717 μm,平均值介于0.148-0.167 μm。晴天条件下,气溶胶的数浓度随高度递减,直径随高度变化不大;逆温层底气溶胶明显积累,气溶胶浓度在大气边界层内明显高于其他层次;阴天轻雾情况下边界层内的气溶胶数浓度大于雨天和晴天,雨天气溶胶浓度最低;晴天气溶胶数浓度的水平分布不均匀;在云中气溶胶浓度明显下降,在云外气溶胶浓度较高。不同天气条件和晴天不同高度情况下,石家庄地区气溶胶谱型呈单峰分布,小于0.3 μm的细粒子对气溶胶的数浓度贡献最大,且随着高度的增加谱宽变窄。