Seasonal variation and ecosystem dependence of emission factors for selected trace gases and PM2.5 for southern African savanna fires
Seasonal variation and ecosystem dependence of emission factors for selected trace gases and PM2.5 for southern African savanna fires
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南部非洲稀树草原火灾选定微量气体和 PM2.5 排放因子的季节变化和生态系统依赖性
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发表时间：
2003
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通讯作者：
W. Hao
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作者：
S. Korontzi;D. Ward;R. Susott;R. Yokelson;C. Justice;P. Hobbs;E. Smithwick;W. Hao
[1]在本文中，我们提出了第一个早期旱季（6月初至8月初）的二氧化碳（CO2），一氧化碳（CO），甲烷（CH 4），非甲烷碳氢化合物（NMHC），和直径小于2.5 μm的颗粒物（PM2.5）的排放因子测量南部非洲草原和林地火灾。草原火灾的季节性排放因子与绿色草的比例呈线性相关，用作燃料水分含量的替代品，在旱季的早期与旱季的后期相比，不完全燃烧的产物较高。草地生态系统NMHC和PM2.5的排放因子与修正燃烧效率（MCE）的模型与林地生态系统相比存在统计学差异。我们比较预测的基础上整合的排放因子从这项研究中，从南部非洲火灾大气研究倡议1992年（SAFARI-92），并从SAFARI-2000与那些基于较小的生态系统特定的排放因子，以估计使用区域平均，而不是生态系统特定的排放因子的影响。我们还测试的有效性，使用SAFARI-92模型的排放因子与MCE预测在这项研究中测量的旱季早期排放因子。比较表明，最大差异发生在本研究中测量的MCE值的低端（0.907）和高端（0.972）。最后，我们结合联合收割机我们的模型MCE与比例的绿色草草原火灾的排放因子与MCE选择氧化挥发性有机化合物测量的SAFARI-2000运动，以获得这些化合物的第一个季节性排放因子。这项研究的结果表明，热带稀树草原火灾排放的季节性变化是很重要的，应该考虑在区域到大陆尺度的排放建模。
[1] In this paper we present the first early dry season (early June-early August) emission factor measurements for carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nonmethane hydrocarbons (NMHC), and particulates with a diameter less than 2.5 μm (PM2.5) for southern African grassland and woodland fires. Seasonal emission factors for grassland fires correlate linearly with the proportion of green grass, used as a surrogate for the fuel moisture content, and are higher for products of incomplete combustion in the early part of the dry season compared with later in the dry season. Models of emission factors for NMHC and PM2.5 versus modified combustion efficiency (MCE) are statistically different in grassland compared with woodland ecosystems. We compare predictions based on the integration of emissions factors from this study, from the Southern African Fire-Atmosphere Research Initiative 1992 (SAFARI-92), and from SAFARI-2000 with those based on the smaller set of ecosystem-specific emission factors to estimate the effects of using regional-average rather than ecosystem-specific emission factors. We also test the validity of using the SAFARI-92 models for emission factors versus MCE to predict the early dry season emission factors measured in this study. The comparison indicates that the largest discrepancies occur at the low end (0.907) and high end (0.972) of MCE values measured in this study. Finally, we combine our models of MCE versus proportion of green grass for grassland fires with emission factors versus MCE for selected oxygenated volatile organic compounds measured in the SAFARI-2000 campaign to derive the first seasonal emission factors for these compounds. The results of this study demonstrate that seasonal variations in savanna fire emissions are important and should be considered in modeling emissions at regional to continental scales.