Aerosol concentrations and size distribution in the troposphere and lower stratosphere over Thumba

Rocket-borne ultraviolet photometers operating at =0.31 m have been used at Thumba (8°33N, 76°52E) to make measurements of atmospheric scattering at tropospheric and lower stratospheric altitudes. Measurements could be made of the amplitude of the scattered fluxes and the angular distribution up to an altitude of about 24 km on three rocket flights conducted as part of the 16 February 1980 solar eclipse campaign. These measurements have been used to study the size distribution as well as the number densities of aerosols in the troposphere and lower stratosphere over Thumba.     

北京地区春末-秋初气溶胶理化特性的观测研究

分析了1997年5～9月和1998年4～9月北京整层大气气溶胶光学厚度、近地面气溶胶粒子数浓度的日变化、季节变化及其与气象要素的关系,还分析了 1997年5月16日、7月21日和8月2日收集的北京单个气溶胶粒子样品的形态、大小和化学元素组成.结果显示,北京地区春末-秋初整层大气气溶胶光学厚度在0.1～1.6之间变化;气溶胶数浓度(D>0.3μm)为几～几百个/cm3;整层大气气溶胶光学厚度的日变化型式与近地面气溶胶数浓度呈现相反的走向;气溶胶光学厚度和数浓度的日、季节变化显示了整层大气和近地面大气气溶胶与该地区气象、气候条件的关系.气溶胶数浓度与大气相对湿度呈正相关,与风向的关系是偏东风数浓度大,西、西南风数浓度小.电子显微镜分析的结果表明:颗粒物的形态以不规则形、丸形、液态滴形和方形为主;颗粒物化学元素组成有Si、K、S、Al、Mg、Ca、Fe等元素;人类活动排放的Zn、P、Ti、pb、Ba等元素也探测到;北京近地面粒子的一个显著特点是富含Ca和K元素,它们可能分别来自建筑粉尘和有机物的燃烧;给出了一个典型的碳黑粒子和一个粒子经过凝结过程的"卫星"滴环绕的矿物粒子的照片和元素谱图.     

VARIABILITY OF AEROSOL OPTICAL PROPERTIES OVER HEFEI DURING SEPTEMBER 1993 TO SEPTEMBER 1994

An 8-wavelength sun-photometer has been operated at Hefei (31.31°N, 117.17°E) to monitoroptical properties of atmospheric aerosols. Altogether 133 solar spectral extinction data were ob-tained on clear days during the period from September 1993 through September 1994, In this pa-per, the feature of the sun-photometer is briefly described. A relative aureole method is intro-duced. which can be used to monitor temporal evolution of aerosol loading during the sun-pho-tometer calibration period. Temporal variabilities of spectral aerosol optical depths and Angstromturbidity parameters are presented. Relation of these variabilities with synoptic and local meteoro-logical conditions are analyzed and discussed, From measured spectral aerosol optical depths undersome representative atmospheric conditions, columnar aerosol size distributions have been retrievedby a linearly constrained inversion method. These typical columnar aerosol size distributions are al-so presented and discussed.     

考虑湿度影响的城市气溶胶夜晚温度效应

本文利用一维非定常模式，研究了城市上空干、湿气溶胶粒子对夜间边界层温度的影响。结果表明，湿气溶胶粒子对低层大气有明显的升温作用，而对中上层大气则起降温作用，同时改变了贴地逆温层结构和边界层稳定度。     

大气臭氧与气溶胶垂直分布的高空气球探测

本文给出了1993年9月12日利用高空科学气球在河北省香河地区探测到的大气臭氧和气溶胶的垂直分布。结果发现:(1) 大气臭氧的数密度在整个对流层较低(～10[12]mol/cm3)，并从地面到对流层顶略有下降；对流层顶以上开始快速增加，极值层高度在～24 km，其值为4.78×10[12]mol/cm3；臭氧分压有类似的分布特征，极值146×10[-4]Pa，位于同一高度；(2) 在平流层低层，臭氧分压有一个次极值62×10[-4]Pa，位于15～16 km；(3) 0～30 km大气气溶胶数密度呈现出三个峰值:143，8和1.1 个/cm[3]，分别位于近地面、5 km和21 km；（4）气溶胶的数密度谱在对流层为双模态；在平流层，次峰消失。同时，我们还与其他观测结果作了比较分析。     

火山气溶胶的辐射影响

本文应用辐射传输计算研究了火山气溶胶,特别是大的火山爆发后短时期及火山周围地区内的火山气溶胶,对到达地面的向下的总的太阳辐射通量、行星反照率及大气加热率的可能影响.     

Products and Mechanism of the Gas Phase Reaction of Ozone with β-Pinene

Gas phase ozonolysis of -pinene was performedin a 570 l static reactor at 730 Torr and 296 K insynthetic air and the products were analysed by acombination of gas phase FTIR spectroscopy, HPLC andIC analyses of gas phase and aerosol samples,respectively. The reaction mechanism was investigatedby adding HCHO, HCOOH and H₂O as Criegeeintermediate scavenger and cyclohexane as OH radicalscavenger. Main identified products (yields inparentheses) in the presence of cyclohexane as OHradical scavenger were HCHO (0.65 ± 0.04),nopinone (0.16 ± 0.04), 3-hydroxy-nopinone (0.15± 0.05), CO₂ (0.20 ± 0.04), CO (0.030± 0.002), HCOOH (0.020 ± 0.002), the secondaryozonide of -pinene (0.16 ± 0.05), andcis-pinic acid (0.02 ± 0.01). The decompositionof the primary ozonide was found to yieldpredominantly the excited C₉-Criegee intermediateand HCHO (0.84 ± 0.04) and to a minor extent theexcited CH₂OO intermediate and nopinone (0.16± 0.04). Roughly 40% of the excitedC₉-Criegee intermediate becomes stabilised andcould be shown to react with HCHO, HCOOH and H₂O. The atmospherically important reaction of thestabilised C₉-Criegee intermediate with H₂Owas found to result in a nopinone increase of (0.35± 0.05) and in the formation of H₂O₂(0.24 ± 0.03). Based on the observed products,the unimolecular decomposition/isomerisationchannels of the C₉-Criegee intermediate arediscussed in terms of the hydroperoxide and esterchannels. Subsequent reactions of the nopinonylradical, formed in the hydroperoxide channel, lead tomajor products like 3-hydroxy-nopinone but also tominor products like cis-pinic acid. A mechanismfor the formation of this dicarboxylic acid isproposed and its possible role in aerosol formationprocesses discussed.     

生物质燃烧颗粒物有机示踪化合物的测定和应用

使用气相色谱-质谱法对2002年7月-2003年7月的北京市大气粗、细颗粒物样品中的左旋葡聚糖等糖类化合物进行了测定。结果表明，左旋葡聚糖主要存在于细颗粒中，可以作为示踪化合物来研究生物质燃烧现象。生物质燃烧对北京市大气颗粒物有较重要的贡献。对应于12％-40％的PM2.5有机碳和10％-33％的PM10有机碳。北京市在2002年10月和11月受到明显的生物质燃烧的影响，可能由于农田秸杆焚烧和秋季落叶焚烧。2003年5月7日颗粒物样品受到直线距离约为1000km以外的内蒙古自治区呼伦贝尔市大兴安岭林区森林大火烟雾的影响。生物质燃烧事件具有突发性，可以长距离传输；生物质作为农村生物燃料的使用其燃烧排放具有经常性和持久性的特征。     

Characteristics of Aerosol Ionic Compositions in Summer 2003 at Lin''''an of Yangtze Delta Region

With the size-resolved aerosol mass and ion composition data obtained at Lin'an regional atmospheric pollution monitoring station in July 2003, the size distributions of aerosol mass and ionic components, and the correlations between major ion pairs were analyzed. The primary results indicate that in the period of in-situ measurement, the aerosols are mainly composed of fine particles. The mass of aerosols with size less than 2.1μm accounts for 66% of the total mass of all size ranges, in which about 50% of the mass is contributed by the particles with size less than 0.65μm. Similar to the size distributions of aerosol mass, the water-soluble ions are mainly concentrated in the size range of <0.65μm, accounting for about 77% of the sum of analyzed ions, and the ions within the range of <2.1μm reach 88%. The sulfate, ammonium, and potassium are the dominant ionic components in fine particles (particle size less than 2.1μm). Ion correlation analysis suggests that the sulfates in fine particles are mostly in the compounds of (NH4)2SO4, Na2SO4, and K2SO4, but for submicron particles the sulfates are mainly in the form of (NH4)2SO4.     

Atmospheric Electrification in the Solar System

Atmospheric electrification is not a purely terrestrial phenomenon: all Solar System planetary atmospheres become slightly electrified by cosmic ray ionisation. There is evidence for lightning on Jupiter, Saturn, Uranus and Neptune, and it is possible on Mars, Venus and Titan. Controversy surrounds the role of atmospheric electricity in physical climate processes on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This paper reviews the theory, and, where available, measurements, of planetary atmospheric electricity which is taken to include ion production and ion–aerosol interactions. The conditions necessary for a planetary atmospheric electric circuit similar to Earth’s, and the likelihood of meeting these conditions in other planetary atmospheres, are briefly discussed. Atmospheric electrification could be important throughout the solar system, particularly at the outer planets which receive little solar radiation, increasing the relative significance of electrical forces. Nucleation onto atmospheric ions has been predicted to affect the evolution and lifetime of haze layers on Titan, Neptune and Triton. Atmospheric electrical processes on Titan, before the arrival of the Huygens probe, are summarised. For planets closer to Earth, heating from solar radiation dominates atmospheric circulations. However, Mars may have a global circuit analogous to the terrestrial model, but based on electrical discharges from dust storms. There is an increasing need for direct measurements of planetary atmospheric electrification, in particular on Mars, to assess the risk for future unmanned and manned missions. Theoretical understanding could be increased by cross-disciplinary work to modify and update models and parameterisations initially developed for a specific atmosphere, to make them more broadly applicable to other planetary atmospheres.