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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >AIRBORNE STUDIES OF EMISSIONS FROM SAVANNA FIRES IN SOUTHERN AFRICA .1. AEROSOL EMISSIONS MEASURED WITH A LASER OPTICAL PARTICLE COUNTER
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AIRBORNE STUDIES OF EMISSIONS FROM SAVANNA FIRES IN SOUTHERN AFRICA .1. AEROSOL EMISSIONS MEASURED WITH A LASER OPTICAL PARTICLE COUNTER

机译：南非萨瓦纳火星排放的空中研究.1。激光光学粒子计数器测量的气溶胶排放

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During the SAFARI-92 experiment (Southern Africa Fire Atmosphere Research Initiative, September-October 1992), we flew an instrumented DC-3 aircraft through plumes from fires in various southern African savanna ecosystems. Some fires had been managed purposely for scientific study (e.g., those in Kruger National Park, South Africa), while the others were ''fires of opportunity'' which are abundant during the burning season in southern Africa. We obtained the aerosol (0.1-3.0 mu m diameter) number and mass emission ratios relative to carbon monoxide and carbon dioxide from 21 individual fires. The average particle number emission ratio Delta N/Delta CO (Delta: concentrations in plume minus background concentrations) varied between 14+/-2 cm(-3) ppb(-1) for grasslands and 23+/-7 cm(-3) ppb(-1) for savannas. An exceptionally high value of 43+/-4 cm(-3) ppb(-1) was measured for a sugarcane fire. Similarly, the mass emission ratio Delta M/Delta CO varied from 36+/-6 ng m(-3) ppb(-1) to 83+/-45 ng m(-3) ppb(-1), respectively, with again an exceptionally high value of 124+/-14 ng m(-3) ppb(-1) for the sugarcane fire. The number and mass emission ratios relative to CO depended strongly upon the fire intensity. Whereas the emission ratios varied greatly from one fire to the other, the aerosol number and volume distributions as a function of particle size were very consistent, The average background aerosol size distribution was characterized by three mass modes (0.2-0.4 mu m, approximate to 1.0 mu m, and approximate to 2.0 mu m diameter). On the other hand, the aerosol size distribution in the smoke plumes showed only two mass modes, one centered in the interval 0.2-0.3 mu m and the other above 2 mu m diameter. From our mean emission factor (4+/-1 g kg(-1) dm) we estimate that savanna fires release some 11-18 Tg aerosol particles in the size range 0.1-3.0 mu m annually, a somewhat lower amount than emitted from tropical forest fires. Worldwide, savanna fires emit some 3-8x10(27) particles (in the same size range) annually, which is expected to make a substantial contribution to the cloud condensation nuclei population in the tropics. [References: 24]
机译：在SAFARI-92实验（1992年9月至10月，南部非洲火灾大气研究计划）期间，我们驾驶着装有仪表的DC-3飞机，通过南部非洲热带稀树草原生态系统中的火灾烟气飞行。有些火灾是为科学研究目的而专门管理的（例如，南非克鲁格国家公园的火灾），而另一些则是“机会之火”，在南部非洲的燃烧季节盛行。我们从21次单独的火灾中获得了相对于一氧化碳和二氧化碳的气溶胶（直径为0.1-3.0微米）数量和质量排放比。草地的平均颗粒物排放比Delta N / Delta CO（Delta：羽流中的浓度减去背景浓度）在14 +/- 2 cm（-3）ppb（-1）和23 +/- 7 cm（-3 ）稀树草原的ppb（-1）。对于甘蔗火灾，测量到的异常高的值为43 +/- 4 cm（-3）ppb（-1）。同样，质量排放比Delta M / Delta CO分别从36 +/- 6 ng m（-3）ppb（-1）变为83 +/- 45 ng m（-3）ppb（-1），甘蔗火灾再次达到124 +/- 14 ng m（-3）ppb（-1）的极高值。相对于CO的数量和质量排放比在很大程度上取决于燃烧强度。尽管从一种火到另一种火的排放比变化很大，但气溶胶的数量和体积分布作为粒径的函数却非常一致。平均背景气溶胶的尺寸分布具有三种质量模式（0.2-0.4μm，近似于1.0微米，直径约2.0微米）。另一方面，烟羽中的气溶胶粒径分布仅表现出两种质量模式，一种集中在0.2-0.3微米之间，另一种集中在2微米以上。根据我们的平均排放因子（4 +/- 1 g kg（-1）dm），我们估计稀树草原大火每年释放约11-18 Tg气溶胶颗粒，大小范围为0.1-3.0μm，比从热带森林大火。在全球范围内，稀树草原大火每年都会散发约3-8x10（27）个粒子（在相同大小范围内），这有望为热带地区的云凝结核群做出重要贡献。 [参考：24]

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