Brey Steven J, Barnes Elizabeth A, Pierce Jeffrey R, Wiedinmyer Christine, Fischer Emily V
Department of Atmospheric Science Colorado State University Fort Collins CO USA.
Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder CO USA.
Earths Future. 2018 Oct;6(10):1442-1456. doi: 10.1029/2018EF000972. Epub 2018 Oct 12.
This research contrasts the environmental conditions, meteorological drivers, and air quality impacts of human- and lightning-ignited wildfires in the southeastern and western United States, the two continental U.S. regions with the most wildfire burn area. We use the Fire Program Analysis Wildfire Occurrence Data (FPA FOD) to determine wildfire abundance and ignition sources between 1992 and 2015. We investigate specific ecoregions within these two U.S. regions and find that in the majority of ecoregions, annual lightning- and human-ignited wildfire burn area have similar relationships with key meteorological parameters. We investigate the fuel moisture values where wildfires occur segregated by ignition type and show that within a given ecoregion, the differences in median fuel moisture between ignition types are generally smaller than the differences between ecoregions. Our results suggest that annual wildfire burn area for human- and lightning-ignited wildfires within a given ecoregion are modulated by environmental conditions, and climate change may similarly impact wildfires of both ignition types. Finally, we estimate fine particulate matter emissions for Fire Program Analysis Wildfire Occurrence Data wildfires using the Fire INventory from NCAR model framework. We show that emissions of fine particulate matter from human-ignited wildfires is significant and of a similar total magnitude between the west and southeastern United States. Additionally, the west and southeast have a similar number of wildfires associated with National Weather Service air quality smoke forecasts.
本研究对比了美国东南部和西部由人类引发和雷击引发的野火的环境条件、气象驱动因素及空气质量影响，这两个地区是美国本土野火燃烧面积最大的两个地区。我们使用火灾项目分析野火发生数据（FPA FOD）来确定1992年至2015年间野火的数量及点火源。我们调查了这两个美国地区内特定的生态区，发现大多数生态区内，每年由雷击和人类引发的野火燃烧面积与关键气象参数有着相似的关系。我们调查了按点火类型划分的野火发生地的燃料湿度值，结果表明，在给定的生态区内，不同点火类型之间的中位燃料湿度差异通常小于不同生态区之间的差异。我们的研究结果表明，给定生态区内由人类和雷击引发的野火的年燃烧面积受环境条件调节，气候变化可能同样会影响这两种点火类型的野火。最后，我们使用美国国家大气研究中心火灾排放清单模型框架估算了火灾项目分析野火发生数据中的野火细颗粒物排放量。我们发现，美国西部和东南部由人类引发的野火排放的细颗粒物数量可观，总量相近。此外，西部和东南部与美国国家气象局空气质量烟雾预报相关的野火数量相近。
