Can simple models predict large-scale surface ocean isoprene concentrations?
Can simple models predict large-scale surface ocean isoprene concentrations?
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DOI：
10.5194/acp-16-11807-2016
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发表时间：
2016-09-22
影响因子：
6.3
通讯作者：
Wallace, Douglas W. R.
中科院分区：
文献类型：
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作者：
Booge, Dennis;Marandino, Christa A.;Wallace, Douglas W. R.
我们使用来自三个不同海洋数据集的异戊二烯和相关现场测量数据以及遥感卫星数据来模拟全球海洋异戊二烯排放。我们表明，使用卫星获取的月平均叶绿素a浓度来参数化具有恒定叶绿素的异戊二烯的归一化异戊二烯生产速率比测量的海洋异戊二烯浓度低19+/-12倍。通过使用浮游植物功能类型依赖的生产值和降低水柱中异戊二烯的细菌降解率来改进模型，结果仅导致轻微的低估(系数1.7+/-1.2)。我们使用这个改进的模型计算了2014年全球异戊二烯排放量0.21tgC，是使用原始模型计算的值的两倍。尽管如此，海洋到空气的通量必须至少高出一个数量级，才能说明测量到的大气异戊二烯混合比。这些发现表明，至少有一个异戊二烯的海洋来源缺失，可能是海洋或大气中影响大气数值的其他未知因素。必须调和计算的通量与大气观测之间的差异，以便充分了解海洋来源的异戊二烯作为形成遥远海洋边界层颗粒的前体的重要性。
We use isoprene and related field measurements from three different ocean data sets together with remotely sensed satellite data to model global marine isoprene emissions. We show that using monthly mean satellite-derived chl a concentrations to parameterize isoprene with a constant chl a normalized isoprene production rate underpredicts the measured oceanic isoprene concentration by a mean factor of 19 +/- 12. Improving the model by using phytoplankton functional type dependent production values and by decreasing the bacterial degradation rate of isoprene in the water column results in only a slight underestimation (factor 1.7 +/- 1.2). We calculate global isoprene emissions of 0.21 Tg C for 2014 using this improved model, which is twice the value calculated using the original model. Nonetheless, the sea-to-air fluxes have to be at least 1 order of magnitude higher to account for measured atmospheric isoprene mixing ratios. These findings suggest that there is at least one missing oceanic source of isoprene and, possibly, other unknown factors in the ocean or atmosphere influencing the atmospheric values. The discrepancy between calculated fluxes and atmospheric observations must be reconciled in order to fully understand the importance of marine-derived isoprene as a precursor to remote marine boundary layer particle formation.