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大气主要污染物与细菌气溶胶在冰核核化过程中的作用:对液滴冻结温度的影响

, PP. 692-700

Keywords: 冰核,细菌气溶胶,冰核活性细菌,大气主要污染物,核化,冻结温度

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Abstract:

?冰核细菌气溶胶作为有效云凝结核与冰核可能在大气物理与化学过程和气象过程中起重要作用,其核化特性也受大气和云中气溶胶的物理、化学性质的影响.本研究依据Vali均匀液滴冻结实验的原理,采用改进的液滴冻结仪分别测试了大气典型污染物(硫酸铵;一元羧酸(MCA):甲酸和乙酸钠;二元羧酸(DCA):乙二酸和丙二酸)与不同浓度的细菌菌液(冰核活性细菌Pseudominassyringaepv.lachrymans(PS))和非冰核细菌P.syringaepv.panici(PS0))的冻结温度.结果显示:不同浓度的MCA/DCA(50,75,100μmolL-1)和硫酸铵(100,200,300,400μmolL-1)溶液液滴(10μL)的平均冻结温度范围在-17.0~-20.0℃,相比超纯水液滴的冻结温度(-20.6±1.6)℃,典型大气污染物的加入并未显著提升超纯水液滴的冻结温度,而且污染物溶液浓度的改变对冻结温度没有表现出明显的规律性.冰核细菌PS和非冰核细菌菌液PS0与大气主要污染物(乙酸钠、乙二酸和硫酸铵)混合液的液滴冻结温度测试结果发现:这些污染物质不同程度降低了细菌PS与PS0菌液的冻结温度,即使PS在较低浓度下也可促进大气主要污染物乙酸钠的冻结核活性,提高其冻结温度;当浓度增至106cellsmL-1时,则能显著改变污染物质的冻结核活性;但未发现PS0有此特性.复合污染物溶液浓度接近当前污染大气水平时,对冰核细菌PS和较高浓度级数(106cellsmL-1)的PS0的冻结核活性都显示出了促进效应,表明在当前大气环境条件下,细菌气溶胶确实有可能影响降水过程和气候变化.冰核活性细菌与非活性冰核细菌混合后,只有当冰核细菌浓度级数达到106cellsmL-1时,在混合液中才可表现出高效冰核活性.冰核细菌的浓度值是影响其活性的重要因素,使其在溶液中显示高效冰核活性的菌浓度阈值级数是106cellsmL-1;本研究结果对于人工影响天气过程中,人工冰核的选择和配比方法优化方面具有一定的科学意义.

References

[1]  1 DeMott P J, Prenni A J, Liu X, et al. Predicting global atmospheric ice nuclei distributions and their impacts on climate. Proc Natl Acad Sci USA, 2010, 107: 11217–22??
[2]  2 Bauer H, Giebl H, Hitzenberger R, et al. Airborne bacteria as cloud condensation nuclei. J Geophys Res, 2003, 108: AAC2/1–AAC2/5
[3]  3 Franc G D, Demott P J. Cloud activation of airborne Erwinia carotovora cells. J Appl Meteorol, 1998, 37: 1293–1300??
[4]  4 Morris C E, Georgakopoulos D G, Sands D C. Ice nucleation active bacteria and their potential role in precipitation. J Phys IV France, 2004, 121: 87–103??
[5]  5 Kanakidou M, Seinfeld J H, Pandis S N, et al. Organic aerosol and global climate modelling: A review. Atmos Chem Phys, 2005, 5: 1053–1123??
[6]  6 Acker K, Mertes S, Moller D, et al. Case study of cloud physical and chemical processes in low clouds at Mt. Brocken. Atmos Res, 2002, 64: 41–51??
[7]  7 Marinoni A, Laj P, Sellegri K, et al. Cloud chemistry at the Puy de D?me: Variability and relationships with environmental factors. Atmos Chem Phys Discuss, 2004, 4: 849–886??
[8]  8 Sun J, Ariya P A. Atmospheric organic and bio-aerosols as cloud condensation nuclei (CCN): A review. Atmos Environ, 2006, 40, 5: 795–820
[9]  9 Kawamura K, Usukura K. Distributions of low molecular weight dicarboxylic acids in the North Pacific aerosol samples. J Oceanogr, 1993, 49: 271–283??
[10]  10 Kerminen V M, Ojanen C, Pakkanen T, et al. Low-molecular-weight dicarboxylic acids in an urban and rural atmosphere. J Aerosol Sci, 2000, 3: 349–362
[11]  11 Pruppacher H R, Klett J D. Microphysics of Clouds and Precipitation. 2nd ed. Dordrecht: Kluwer Academic Publishers, 1997
[12]  12 Ariya P A, Amyot M. The role of bioaerosols in atmospheric chemistry and physics. Atmos Environ, 2004, 38: 1231–1232??
[13]  13 Ariya P A, Sun J, Eltouny N A, et al. Physical and chemical characterization of bioaerosols-Implications for nucleation processes. Int Rev Phys Chem, 2009, 28: 1–32??
[14]  14 Maki L R, Willoughby K J. Bacteria as biogenic sources of freezing nuclei. Appl Meteor, 1978, 17: 1049–1053??
[15]  15 Mortazavi R, Hayes C T, Ariya P A. Ice nucleation activity of bacteria isolated from snow compared with organic and inorganic substrate. Environ.Chem, 2008, 5: 373–381
[16]  16 Wang G H, Niu S L, Liu C, et al. Identification of dicarboxylic acids and aldehydes of PM10 and PM2.5 aerosols in Nanjing, China. Atmos Environ, 2002, 36: 1941–1950
[17]  17 Kawamura K, Ikushima K. Seasonal change in the distribution of dicarboxylic acids in the urban atmosphere. Environ Sci Technol, 1993, 27: 2227–2235??
[18]  18 Sempere R, Kawamura K. Comparative distributions of dicarboxylic acids and related polar compounds in snow, rain and aerosols from urban atmosphere. Atmos Environ, 1994, 28: 449–459??
[19]  19 胡敏, 张静, 吴志军. 北京降水化学组成特征及其对大气颗粒物的去除作用. 中国科学B 辑: 化学, 2005, 35: 169–176
[20]  20 Delort A M, Va?tilingom M, Amato P, et al. A short overview of the microbial population in clouds: Potential roles in atmospheric chemistry and nucleation processes. Atmos Res, 2010, 98: 249–260??
[21]  21 杨绍忠, 酆大雄. 一个检测水中冻结核含量的新装置. 气象学报, 2007, 65: 976–982
[22]  22 Vali G. Quantitative evaluation of experimental results on the heterogeneous freezing nucleation of supercooled liquids. Atmos Sci, 1971, 28: 402–409??
[23]  23 Du R, Ariya P A. The freezing temperature of C2-C6 dicarboxylic acid: The important indicator for ice nucleation processes. Chin Sci Bull, 2008, 53: 2685–2691??
[24]  24 Fukuta N. Experimental studies of organic ice nuclei. Atmos Sci, 1966, 23: 191–196??
[25]  25 Gavish M, Wang J L, Eisenstein M, et al. The role of crystal polarity in alpha-amino acid crystals for induced nucleation of ice. Science, 1992, 256: 815–818??
[26]  26 Wise M E, Garland R M, Tolbert M A. Ice nucleation in internally mixed ammonium sulfate/dicarboxylic acid particles. J Geophys Res, 2004, 109: D19203, doi: 10.1029/2003JD004313??
[27]  27 Shilling J E, Fortin T J, Tolbert M A, et al. Depositional ice nucleation on crystalline organic and inorganic solids. J Geophys Res, 2006, 111: D12204
[28]  28 Zobrist B, Marcolli C, Koop T, et al. Oxalic acid as a heterogeneous ice nucleus in the upper troposphere and its indirect aerosol effect. Atmos Chem Phys, 2006, 6: 3115–3129??
[29]  29 Diehl K, Quick C, Matthias-Maser S, et al. The ice nucleating ability of pollen. Part I: Laboratory studies in deposition and condensation freezing modes. Atmos Res, 2001, 8: 75–87
[30]  30 Paul S, Hazra A, De U K, et al. Comparative study of nucleation by different alcoholic solutions of benzoin, and benzoin dust. J Atmos Chem, 2006, 53: 155–168??
[31]  31 Pruppacher H R, Neiburg

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