Biogenic volatile organic compound ambient mixing ratios and emission rates in the Alaskan Arctic tundra.
Biogenic volatile organic compound ambient mixing ratios and emission rates in the Alaskan Arctic tundra.
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DOI：
10.5194/bg-17-6219-2020
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发表时间：
2020
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影响因子：
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通讯作者：
Helmig D
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作者：
Angot H;McErlean K;Hu L;Millet DB;Hueber J;Cui K;Moss J;Wielgasz C;Milligan T;Ketcherside D;Bret-Harte MS;Helmig D
北极迅速变暖，生长季节延长，越来越丰富的生物挥发性有机化合物排放灌木预计都会增加北极大气中的大气生物挥发性有机化合物（BVOCs），对大气氧化过程和气候反馈的影响。量化这些变化需要准确了解推动北极BVOC排放的基本过程。虽然北方生态系统已被广泛研究，很少有人注意到北极苔原环境。在这里，我们报告了在北方阿拉斯加的图里克野外站（TFS; 68°38′ N，149°36′ W），在两个背靠背的野外活动（2018年和2019年夏天）中，覆盖整个生长季节的萜类化合物（异戊二烯，单萜和倍半萜）环境混合比和主要植被物种的排放率。在TFS观察到的异戊二烯环境混合比在欧亚针叶林中报告的值范围内（0-500份/万亿体积- pptv），而单萜和倍半萜环境混合比分别接近和低于仪器定量限（约2 pptv）。异戊二烯的表面释放速率范围为0.2至2250 μgC m−2 h−1（平均值为85 μgC m−2 h−1），单萜的平均释放速率在整个研究过程中保持在1 μgC m−2 h−1以下。我们进一步量化了当地植被（包括柳属）异戊二烯排放的温度依赖性。（一种已知的异戊二烯排放物），并将结果与来自《自然》2.1版的气体和气溶胶排放模型（MEGAN2.1）的预测进行了比较。我们的观测结果表明，3-4°C变暖会导致排放增加180%-215%，MEGAN2.1温度算法与0-30°C范围内的外壳温度观测结果非常吻合。这里提供的数据提供了一个基线，调查未来的变化，在BVOC的排放潜力的研究北极苔原环境。
Rapid Arctic warming, a lengthening growing season, and the increasing abundance of biogenic volatile-organic-compound-emitting shrubs are all anticipated to increase atmospheric biogenic volatile organic compounds (BVOCs) in the Arctic atmosphere, with implications for atmospheric oxidation processes and climate feedbacks. Quantifying these changes requires an accurate understanding of the underlying processes driving BVOC emissions in the Arctic. While boreal ecosystems have been widely studied, little attention has been paid to Arctic tundra environments. Here, we report terpenoid (isoprene, monoterpenes, and sesquiterpenes) ambient mixing ratios and emission rates from key dominant vegetation species at Toolik Field Station (TFS; 68°38′ N, 149°36′ W) in northern Alaska during two back-to-back field campaigns (summers of 2018 and 2019) covering the entire growing season. Isoprene ambient mixing ratios observed at TFS fell within the range of values reported in the Eurasian taiga (0–500 parts per trillion by volume – pptv), while monoterpene and sesquiterpene ambient mixing ratios were respectively close to and below the instrumental quantification limit (~ 2 pptv). Isoprene surface emission rates ranged from 0.2 to 2250 μgC m−2 h−1 (mean of 85 μgC m−2 h−1) and monoterpene emission rates remained, on average, below 1 μgC m−2 h−1 over the course of the study. We further quantified the temperature dependence of isoprene emissions from local vegetation, including Salix spp. (a known isoprene emitter), and compared the results to predictions from the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1). Our observations suggest a 180 %–215 % emission increase in response to a 3–4°C warming, and the MEGAN2.1 temperature algorithm exhibits a close fit with observations for enclosure temperatures in the 0–30°C range. The data presented here provide a baseline for investigating future changes in the BVOC emission potential of the under-studied Arctic tundra environment.