Fluxes and concentrations of volatile organic compounds from a South-East Asian tropical rainforest
Fluxes and concentrations of volatile organic compounds from a South-East Asian tropical rainforest
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DOI：
10.5194/acp-10-8391-2010
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发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Hewitt, C. N.
中科院分区：
文献类型：
--
作者：
Langford, B.;Misztal, P. K.;Hewitt, C. N.
作为热带雨林大气化学OP 3实地研究的一部分，异戊二烯，单萜和氧化挥发性有机化合物的冠层以上通量的虚拟间断涡度协方差从东南亚热带雨林在马来西亚。在2008年4月至5月和6月至7月的48天内收集了大约500小时的通量数据。异戊二烯是森林排放的主要非甲烷碳氢化合物，占实测活性碳通量排放量的80%（以碳计）。总单萜排放量占18%的测得的活性碳通量。没有证据表明夜间单萜排放，白天它们的通量率取决于光照和温度。含氧化合物，包括甲醇，丙酮和乙醛，贡献小于2%的总测量的活性碳通量。测量的VOC通量之和代表冠层白天同化碳的0.4%损失，但大气化学箱模型表明，大部分（90%）活性碳在化学转化后通过湿沉积和干沉积返回冠层。异戊二烯和单萜的排放率，归一化为30摄氏度和1000 μ mol m（-2）s（-1）PAR，分别为1.6 mg m（-2）h（-1）和0.46 mg m（-2）h（-1），这是4和1.8倍，分别低于热带森林的默认值在广泛使用的MEGAN模型的生物源VOC排放。这突出了需要更直接的冠层尺度的挥发性有机化合物通量测量从世界热带森林。
As part of the OP3 field study of rainforest atmospheric chemistry, above-canopy fluxes of isoprene, monoterpenes and oxygenated volatile organic compounds were made by virtual disjunct eddy covariance from a South-East Asian tropical rainforest in Malaysia. Approximately 500 hours of flux data were collected over 48 days in April-May and June-July 2008. Isoprene was the dominant non-methane hydrocarbon emitted from the forest, accounting for 80% (as carbon) of the measured emission of reactive carbon fluxes. Total monoterpene emissions accounted for 18% of the measured reactive carbon flux. There was no evidence for nocturnal monoterpene emissions and during the day their flux rate was dependent on both light and temperature. The oxygenated compounds, including methanol, acetone and acetaldehyde, contributed less than 2% of the total measured reactive carbon flux. The sum of the VOC fluxes measured represents a 0.4% loss of daytime assimilated carbon by the canopy, but atmospheric chemistry box modelling suggests that most (90%) of this reactive carbon is returned back to the canopy by wet and dry deposition following chemical transformation. The emission rates of isoprene and monoterpenes, normalised to 30 degrees C and 1000 mu mol m(-2) s(-1) PAR, were 1.6 mg m(-2) h(-1) and 0.46mg m(-2) h(-1) respectively, which was 4 and 1.8 times lower respectively than the default value for tropical forests in the widely-used MEGAN model of biogenic VOC emissions. This highlights the need for more direct canopy-scale flux measurements of VOCs from the world's tropical forests.