Satellite-observed pollution from Southern Hemisphere biomass burning
Satellite-observed pollution from Southern Hemisphere biomass burning
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DOI：
10.1029/2005jd006655
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发表时间：
2006-07-26
影响因子：
4.4
通讯作者：
Drummond, J. R.
中科院分区：
文献类型：
--
作者：
Edwards, D. P.;Emmons, L. K.;Drummond, J. R.
生物质燃烧是南半球热带地区的一个主要污染源，细态碳质颗粒的产生与排放一氧化碳（CO）的燃烧过程相同。在本文中，我们用Terra卫星的数据、对流层污染测量（MOPITT）仪器的CO剖面和中分辨率成像光谱仪（MODIS）的精细模式气溶胶光学深度（AOD）来研究这些排放。卫星测量结果与MOZART化学传输模型的计算结合使用，对2003年南半球燃烧季节进行了考察，特别强调了9月和10月的火灾活动高峰。污染物排放随旱季火灾的发生而变化，MOPITT CO和MODIS AOD的时间变化和空间分布相似。我们研究了来自非洲和南美洲的外流，重点是这些排放对清洁偏远地区的影响。我们将MOPITT观测数据与来自新西兰Lauder的地面干涉仪数据进行了比较，结果表明非洲生物质燃烧污染的洲际运输往往决定了当地的空气质量。不同类型生物质燃烧羽流AOD与CO柱的相关性均大于0.8。我们提出了一种使用MOPITT和MODIS数据来估计气溶胶数密度与CO浓度的排放比的方法，这可能被证明是建模研究的有用输入。我们还研究了非洲大火产生的羽状物在出口到印度洋后的衰减，并比较了MOPITT和MODIS的测量结果，作为估计区域气溶胶寿命的一种方法。利用CO剖面信息研究了生物质燃烧排放的垂直输送。靠近源区的低空浓度非常高，但在大陆的下风处，发生垂直混合并导致更均匀的CO垂直分布。在对流显著的区域，特别是在赤道印度洋，CO混合比在高海拔处更大，表明生物质燃烧排放垂直输送到对流层上层。
[1] Biomass burning is a major source of pollution in the tropical Southern Hemisphere, and fine mode carbonaceous particles are produced by the same combustion processes that emit carbon monoxide ( CO). In this paper we examine these emissions with data from the Terra satellite, CO profiles from the Measurement of Pollution in the Troposphere (MOPITT) instrument, and fine-mode aerosol optical depth (AOD) from the Moderate-Resolution Imaging Spectroradiometer ( MODIS). The satellite measurements are used in conjunction with calculations from the MOZART chemical transport model to examine the 2003 Southern Hemisphere burning season with particular emphasis on the months of peak fire activity in September and October. Pollutant emissions follow the occurrence of dry season fires, and the temporal variation and spatial distributions of MOPITT CO and MODIS AOD are similar. We examine the outflow from Africa and South America with emphasis on the impact of these emissions on clean remote regions. We present comparisons of MOPITT observations and ground-based interferometer data from Lauder, New Zealand, which indicate that intercontinental transport of biomass burning pollution from Africa often determines the local air quality. The correlation between enhancements of AOD and CO column for distinct biomass burning plumes is very good with correlation coefficients greater than 0.8. We present a method using MOPITT and MODIS data for estimating the emission ratio of aerosol number density to CO concentration which could prove useful as input to modeling studies. We also investigate decay of plumes from African fires following export into the Indian Ocean and compare the MOPITT and MODIS measurements as a way of estimating the regional aerosol lifetime. Vertical transport of biomass burning emissions is also examined using CO profile information. Low-altitude concentrations are very high close to source regions, but further downwind of the continents, vertical mixing takes place and results in more even CO vertical distributions. In regions of significant convection, particularly in the equatorial Indian Ocean, the CO mixing ratio is greater at higher altitudes, indicating vertical transport of biomass burning emissions to the upper troposphere.