Temporal variation of VOC fluxes measured with PTR-TOF above a boreal forest
Temporal variation of VOC fluxes measured with PTR-TOF above a boreal forest
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DOI：
10.5194/acp-18-815-2018
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发表时间：
2018-01-23
影响因子：
6.3
通讯作者：
Kulmala, Markku
中科院分区：
文献类型：
--
作者：
Schallhart, Simon;Rantala, Pekka;Kulmala, Markku
在2013年4月至6月期间，使用涡动协方差（EC）方法和质子转移反应飞行时间（PTR-TOF）质谱仪测量了苏格兰松和挪威云杉森林中挥发性有机化合物（VOCs）的通量。观测是在芬兰南部的SMEAR II站点的北方森林上进行的，我们发现了25种不同的化合物，并研究了它们从春季到夏季的季节变化。大部分净VOC通量由甲醇、单萜、丙酮和丁烯+丁醇组成。丁烯+丁醇排放的结论是，不是来自森林，因此，是人为的。挥发性有机化合物的交换遵循季节性的趋势，从春季到夏季的排放量增加。只有三种化合物在融雪期间排放，而在夏季排放的约19挥发性有机化合物进行了观察。在4月份的测量期间，排放物主要是丁烯+丁醇，而在生长季节开始和夏季，甲醇是排放最多的化合物。甲醇的主要来源可能是新生物质的生长。在6月的21天期间，净VOC通量为2.1 nmolm 2 s（-1）。这是在其他生态系统的PTR-TOF通量测量的低端，范围从2到10 nmolm 2 s（-1）。EC通量的结果进行了比较与表面层的轮廓测量，使用质子转移反应四极质谱仪，这是永久安装在SMEAR II网站。对于主要化合物，两种不同的方法测量的通量一致。
Between April and June 2013 fluxes of volatile organic compounds (VOCs) were measured in a Scots pine and Norway spruce forest using the eddy covariance (EC) method with a proton transfer reaction time-of-flight (PTR-TOF) mass spectrometer. The observations were performed above a boreal forest at the SMEAR II site in southern Finland.We found a total of 25 different compounds with exchange and investigated their seasonal variations from spring to summer. The majority of the net VOC flux was comprised of methanol, monoterpenes, acetone and butene + butanol. The butene + butanol emissions were concluded to not originate from the forest and, therefore, be anthropogenic. The VOC exchange followed a seasonal trend and the emissions increased from spring to summer. Only three compounds were emitted during the snowmelt while in summer emissions of some 19 VOCs were observed. During the measurement period in April, the emissions were dominated by butene + butanol, while during the start of the growing season and in summer, methanol was the most emitted compound. The main source of methanol was likely the growth of new biomass. During a 21-day period in June, the net VOC flux was 2.1 nmolm 2 s(-1). This is on the lower end of PTR-TOF flux measurements from other ecosystems, which range from 2 to 10 nmolm 2 s(-1). The EC flux results were compared with surface layer profile measurements, using a proton transfer reaction quadrupole mass spectrometer, which is permanently installed at the SMEAR II site. For the major compounds, the fluxes measured with the two different methods agreed well.