Significant enhancements of nitrogen oxides, black carbon, and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires
Significant enhancements of nitrogen oxides, black carbon, and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires
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DOI：
10.1029/2006jd007530
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发表时间：
2006-12-07
影响因子：
4.4
通讯作者：
Barata, F.
中科院分区：
文献类型：
--
作者：
Martin, M. Val;Honrath, R. E.;Barata, F.
2004年夏季，北美北方发生了大面积的野火，向大气中释放了大量的痕量气体和气溶胶。这些野火的排放物经常影响PICO-NARE站，这是一个位于亚速尔群岛火灾顺风6-15天的山顶站点。为了评估北方野火排放对北美下风向气溶胶黑碳（BC），氮氧化物和O-3水平的影响，我们分析了2004年6月至9月的CO，BC，总活性氮氧化物（NOy），NOx（NO + NO2）和O-3的测量与MOZART化学传输模型模拟相结合。北方野火排放物的远距离传输导致CO、BC、NOy和NOx的大量增加，水平分别高达250 ppbv、665 ng m（-3）、1100 pptv和135 pptv。在采样的羽流中，相对于CO的增强率各不相同，最有可能是由于野火排放和传输过程中的去除过程的变化。Δ BC/Δ CO、Δ NOy/Δ CO和Δ NOx/Δ CO比率的分析表明，平均而言，NOy和BC在这些羽流中有效地输出，并表明PAN分解成NOx是NOx的重要来源。高水平的氮氧化物表明在这些成熟的羽流中继续形成O-3。烟羽中的O-3水平也显著提高，达到75 ppbv。δ O-3/δ CO比值的分析表明，不同的行为的O-3的羽流，这从显着到较低的O-3生产。我们确定了几个潜在的原因，对O-3的北方野火排放的复杂影响，并得出结论，这种行为需要在未来进一步探讨。这些观测结果表明，北方野火排放显着的氮氧化物和O-3预算在北大西洋中部较低的自由对流层在2004年夏季，并意味着大规模的影响，对大气的直接辐射强迫和对流层的氮氧化物和O-3。
Extensive wildfires burned in northern North America during summer 2004, releasing large amounts of trace gases and aerosols into the atmosphere. Emissions from these wildfires frequently impacted the PICO-NARE station, a mountaintop site situated 6-15 days downwind from the fires in the Azores Islands. To assess the impacts of the boreal wildfire emissions on the levels of aerosol black carbon (BC), nitrogen oxides and O-3 downwind from North America, we analyzed measurements of CO, BC, total reactive nitrogen oxides (NOy), NOx (NO + NO2) and O-3 made from June to September 2004 in combination with MOZART chemical transport model simulations. Long-range transport of boreal wildfire emissions resulted in large enhancements of CO, BC, NOy and NOx, with levels up to 250 ppbv, 665 ng m(-3), 1100 pptv and 135 pptv, respectively. Enhancement ratios relative to CO were variable in the plumes sampled, most likely because of variations in wildfire emissions and removal processes during transport. Analyses of Delta BC/Delta CO, Delta NOy/ Delta CO and Delta NOx/Delta CO ratios indicate that NOy and BC were on average efficiently exported in these plumes and suggest that decomposition of PAN to NOx was a significant source of NOx. High levels of NOx suggest continuing formation of O-3 in these well-aged plumes. O-3 levels were also significantly enhanced in the plumes, reaching up to 75 ppbv. Analysis of Delta O-3/Delta CO ratios showed distinct behaviors of O-3 in the plumes, which varied from significant to lower O-3 production. We identify several potential reasons for the complex effects of boreal wildfire emissions on O-3 and conclude that this behavior needs to be explored further in the future. These observations demonstrate that boreal wildfire emissions significantly contributed to the NOx and O-3 budgets in the central North Atlantic lower free troposphere during summer 2004 and imply large-scale impacts on direct radiative forcing of the atmosphere and on tropospheric NOx and O-3.