Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station.
Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station.
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DOI：
10.5194/acp-22-14037-2022
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发表时间：
2022
影响因子：
6.3
通讯作者：
Hu L
中科院分区：
文献类型：
--
作者：
Selimovic V;Ketcherside D;Chaliyakunnel S;Wielgasz C;Permar W;Angot H;Millet DB;Fried A;Helmig D;Hu L
北极是一个气候敏感的地区，近几十年来，北极的变暖速度几乎是全球平均速度的3倍，导致北极绿色增加，释放生物挥发性有机化合物（BVOC）的植物数量增加。这些大气排放的变化预计将大大改变该区域的整体氧化化学，并导致挥发性有机化合物的组成和丰度的变化，对大气过程产生影响。尽管如此，在这个关键的环境中，限制我们目前对这些问题的理解所需的观察很少。这项工作提出了2019年5月至6月期间在阿拉斯加北极苔原的图利克野外站（TFS; 68°38′ N，149°36 ′ W）对VOCs进行的新型大气原位质子转移反应飞行时间质谱（PTR-ToF-MS）测量。我们采用自定义嵌套网格版本的GEOS-Chem化学传输模型（CTM），驱动MEGANv2.1（来自自然界的气体和气溶胶排放模型2.1版）阿拉斯加生物源排放，分辨率为0.25° × 0.3125°，以解释观测结果对BVOC排放、总活性有机碳（ROC）组成的限制，并计算了该环境中的OH反应性（OHr）。我们发现78种已鉴定的VOC的总环境摩尔分数为6.3 ± 0.4 ppbv（10.8 ± 0.5 ppbC），其中绝大多数（> 80%）来自短链含氧VOC（OVOC），包括甲醇，丙酮和甲醛。异戊二烯是已发现的最丰富的萜烯。GEOS-Chem将观测到的异戊二烯（及其氧化产物）、丙酮和乙醛丰度纳入了综合模型和观测不确定性（± 25%）范围内，但将其他OVOCs（包括甲醇、甲醛、甲酸和乙酸）低估了3至12倍。甲醇的负模型偏差是由于低估了MEGANv2.1中阿拉斯加苔原的生物甲醇排放。观测到的甲醛摩尔分数随空气温度呈指数增加，可能反映了其生物前体，并指出其二次生产的系统模型预测不足。在TFS测得的VOC中，OHr的中位数为0.7 s-1，大约是低纬度森林生态系统中通常报告的值的5%。十种物质占计算的VOC OHr的80%以上，其中甲醛、异戊二烯和乙醛加起来占总量的近一半。基于GEOS-Chem中包含的中位数模型VOC的模拟OHr平均值为0.5 s-1，主要是异戊二烯（30%）和单萜（17%）。这里提供的数据作为我们在高纬度环境中的BVOCs和ROC预算的知识的关键评估，并代表了调查和解释未来变暖驱动的阿拉斯加北极苔原VOC排放变化的基础。
The Arctic is a climatically sensitive region that has experienced warming at almost 3 times the global average rate in recent decades, leading to an increase in Arctic greenness and a greater abundance of plants that emit biogenic volatile organic compounds (BVOCs). These changes in atmospheric emissions are expected to significantly modify the overall oxidative chemistry of the region and lead to changes in VOC composition and abundance, with implications for atmospheric processes. Nonetheless, observations needed to constrain our current understanding of these issues in this critical environment are sparse. This work presents novel atmospheric in situ proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) measurements of VOCs at Toolik Field Station (TFS; 68°38′ N, 149°36’ W), in the Alaskan Arctic tundra during May–June 2019. We employ a custom nested grid version of the GEOS-Chem chemical transport model (CTM), driven with MEGANv2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) biogenic emissions for Alaska at 0.25° × 0.3125° resolution, to interpret the observations in terms of their constraints on BVOC emissions, total reactive organic carbon (ROC) composition, and calculated OH reactivity (OHr) in this environment. We find total ambient mole fraction of 78 identified VOCs to be 6.3 ± 0.4 ppbv (10.8 ± 0.5 ppbC), with overwhelming (> 80 %) contributions are from short-chain oxygenated VOCs (OVOCs) including methanol, acetone and formaldehyde. Isoprene was the most abundant terpene identified. GEOS-Chem captures the observed isoprene (and its oxidation products), acetone and acetaldehyde abundances within the combined model and observation uncertainties (±25 %), but underestimates other OVOCs including methanol, formaldehyde, formic acid and acetic acid by a factor of 3 to 12. The negative model bias for methanol is attributed to underestimated biogenic methanol emissions for the Alaskan tundra in MEGANv2.1. Observed formaldehyde mole fractions increase exponentially with air temperature, likely reflecting its biogenic precursors and pointing to a systematic model underprediction of its secondary production. The median campaign-calculated OHr from VOCs measured at TFS was 0.7 s−1, roughly 5 % of the values typically reported in lower-latitude forested ecosystems. Ten species account for over 80 % of the calculated VOC OHr, with formaldehyde, isoprene and acetaldehyde together accounting for nearly half of the total. Simulated OHr based on median-modeled VOCs included in GEOS-Chem averages 0.5 s−1 and is dominated by isoprene (30 %) and monoterpenes (17 %). The data presented here serve as a critical evaluation of our knowledge of BVOCs and ROC budgets in high-latitude environments and represent a foundation for investigating and interpreting future warming-driven changes in VOC emissions in the Alaskan Arctic tundra.
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影响因子：
4.4
作者：
Eyring, V;Köhler, HW;Lauer, A
通讯作者：
Lauer, A
影响因子：
64.8
作者：
Franco B;Blumenstock T;Cho C;Clarisse L;Clerbaux C;Coheur PF;De Mazière M;De Smedt I;Dorn HP;Emmerichs T;Fuchs H;Gkatzelis G;Griffith DWT;Gromov S;Hannigan JW;Hase F;Hohaus T;Jones N;Kerkweg A;Kiendler-Scharr A;Lutsch E;Mahieu E;Novelli A;Ortega I;Paton-Walsh C;Pommier M;Pozzer A;Reimer D;Rosanka S;Sander R;Schneider M;Strong K;Tillmann R;Van Roozendael M;Vereecken L;Vigouroux C;Wahner A;Taraborrelli D
通讯作者：
Taraborrelli D
DOI：
10.5194/bg-17-6219-2020
发表时间：
2020
期刊：
Biogeosciences (Online)
影响因子：
--
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
通讯作者：
Helmig D
影响因子：
4.4
作者：
Apel, EC;Riemer, DD;Geron, CD
通讯作者：
Geron, CD
影响因子：
6.3
作者：
Gong, Wanmin;Beagley, Stephen R.;Holt, Richard
通讯作者：
Holt, Richard