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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >AEROSOLS FROM BIOMASS BURNING OVER THE TROPICAL SOUTH ATLANTIC REGION - DISTRIBUTIONS AND IMPACTS
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AEROSOLS FROM BIOMASS BURNING OVER THE TROPICAL SOUTH ATLANTIC REGION - DISTRIBUTIONS AND IMPACTS

机译：热带南大西洋地区生物量燃烧产生的气溶胶-分布和影响

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The NASA Global Tropospheric Experiment (GTE) Transport and Atmospheric Chemistry Near the Equator-Atlantic (TRACE A) expedition was conducted September 21 through October 26, 1992 to investigate factors responsible for creating the seasonal South Atlantic tropospheric ozone maximum. During these flights, fine aerosol(0.1-3.0 mu m) number densities were observed to be enhanced roughly tenfold over remote regions of the tropical South Atlantic and greater over adjacent continental areas, relative to northern hemisphere observations and to measurements recorded in the same area during the wet season. Chemical and meteorological analyses as well as visual observations indicate that the primary source of these enhancements was biomass burning occurring within grassland regions of north central Brazil and southeastern Africa. These fires exhibited fine aerosol (N) emission ratios relative to CO (dN/dCO) of 22.5 +/- 9.7 and 23.6 +/- 15.1 cm(-3) parts per billion by volume (ppbv)(-1) over Brazil and Africa, respectively. Convection coupled with counterclockwise now around the South Atlantic subtropical anticyclone subsequently distributed these aerosols throughout the remote South Atlantic troposphere. We calculate that dilute smoke from biomass burning produced an average tenfold enhancement in optical depth over the continental regions as well as a 50% increase in this parameter over the middle South Atlantic Ocean; these changes correspond to an estimated net cooling of up to 25 W m(-2) and 2.4 W m(-2) during clear-sky conditions over savannas and ocean respectively. Over the ocean our analyses suggest that modification of CCN concentrations within the persistent eastern Atlantic marine stratocumulus clouds by entrainment of subsiding haze layers could significantly increase cloud albedo resulting in an additional surface radiative cooling potentially greater in magnitude than that caused by direct extinction of solar radiation by the aerosol particles themselves. [References: 56]
机译：1992年9月21日至10月26日，进行了NASA全球对流层实验（GTE）赤道-大西洋附近的运输和大气化学（TRACA）考察，以调查造成南大西洋对流层季节性臭氧最大值的因素。在这些飞行中，相对于北半球的观测值和在同一区域记录的测量值，观测到的细小气溶胶（0.1-3.0μm）的数量密度在热带南大西洋的偏远地区大约增加了十倍，而在相邻大陆区域则增加了约十倍。在雨季。化学和气象分析以及目视观察表明，这些增强作用的主要来源是巴西中北部和非洲东南部的草原地区发生的生物质燃烧。这些大火表现出相对于CO（dN / dCO）的细小气溶胶（N）排放比，在巴西和巴西每10亿体积（ppbv）（-1）分别为22.5 +/- 9.7和23.6 +/- 15.1 cm（-3）份。非洲分别。现在，对流加上逆时针在南大西洋亚热带反气旋周围，随后将这些气溶胶分布在整个南大西洋对流层中。我们计算出，生物质燃烧产生的稀烟在大陆区域的光学深度平均增加了十倍，而在中大西洋南部的这一参数增加了50％;这些变化分别对应于稀树草原和海洋上晴空条件下估计高达25 W m（-2）和2.4 W m（-2）的净冷却。在海洋上，我们的分析表明，通过夹带下沉的雾霾层来改变大西洋东部持久的平流层积云内CCN的浓度可能会显着增加云的反照率，从而导致额外的表面辐射降温，其潜在强度可能比太阳辐射的直接消亡更大。通过气溶胶颗粒本身。 [参考：56]

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