Extracting a History of Global Fire Emissions for the Past Millennium From Ice Core Records of Acetylene, Ethane, and Methane
Extracting a History of Global Fire Emissions for the Past Millennium From Ice Core Records of Acetylene, Ethane, and Methane
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DOI：
10.1029/2020jd032932
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发表时间：
2020-10
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影响因子：
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通讯作者：
M. R. Nicewonger;M. Aydin;M. Prather;E. Saltzman
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文献类型：
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作者：
M. R. Nicewonger;M. Aydin;M. Prather;E. Saltzman
从全球生物地球化学、大气组成、气候、陆地生态和土地利用等方面来看，生物质燃烧是地球系统的重要组成部分。这项研究考察了已发表的冰芯微量气体乙炔、乙烷和甲烷的测量结果，这些气体已被用作古火灾排放的替代品。我们从(1)全球火灾排放的时间趋势和(2)全球燃烧(每年燃烧的干物质)变化的定量估计两个方面考察了这些记录在过去1000年中的一致性。使用三维传输和盒子模型来构建与每个冰芯记录一致的痕量气体的排放情景。通过考虑每种痕量气体的生物群特定排放因子，从微量气体排放中推断燃烧历史。从微量气体推断的火灾的时间趋势是合理的，从中世纪时期(MP：1000-1500 CE)到小冰期(LIA：1650-1750 CE)，生物质燃烧排放大幅下降。然而，即使假设火和生物群的空间分布发生了戏剧性的(和不切实际的)变化，三个痕量气体冰芯记录也不能产生一致的火灾历史。似乎需要对气象输送或大气光化学寿命等其他因素进行重大改变，才能对痕量气体记录进行核对。
Biomass burning is an important component of the Earth system in terms of global biogeochemistry, atmospheric composition, climate, terrestrial ecology, and land use. This study examines published ice core trace gas measurements of acetylene, ethane, and methane, which have been used as proxies for paleofire emissions. We investigate the consistency of these records for the past 1,000 years in terms of (1) temporal trends in global fire emissions and (2) quantitative estimates for changes in global burning (dry matter burned per year). Three‐dimensional transport and box models were used to construct emissions scenarios for the trace gases consistent with each ice core record. Burning histories were inferred from trace gas emissions by accounting for biome‐specific emission factors for each trace gas. The temporal trends in fire inferred from the trace gases are in reasonable agreement, with a large decline in biomass burning emissions from the Medieval Period (MP: 1000–1500 CE) to the Little Ice Age (LIA: 1650–1750 CE). However, the three trace gas ice core records do not yield a consistent fire history, even assuming dramatic (and unrealistic) changes in the spatial distribution of fire and biomes. Substantial changes in other factors such as meteorological transport or atmospheric photochemical lifetimes appear to be required to reconcile the trace gas records.