Estimates of tropical bromoform emissions using an inversion method
Estimates of tropical bromoform emissions using an inversion method
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DOI：
10.5194/acp-14-979-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Pyle, J. A.
中科院分区：
文献类型：
--
作者：
Ashfold, M. J.;Harris, N. R. P.;Pyle, J. A.
溴在对流层和平流层的臭氧化学中起着重要作用。按质量计算，溴仿（CHBr 3）被认为是大气中溴的最大有机来源。虽然海藻和浮游植物是已知的主要来源，但三溴甲烷排放量的规模和地理分布仍不确定。人们对来自海洋大陆的排放量知之甚少，人们通常认为海洋大陆的排放量很大，而且似乎特别有可能到达平流层。在这项研究中，我们的目标是减少这种不确定性相结合的第一个多年度的CHBr 3测量从该地区，和反演过程，系统地调查CHBr 3排放的分布和幅度。我们的方法的新奇在于应用的反演方法CHBr 3。我们发现，本地测量的短寿命的气体，如CHBr 3可以用来限制排放量只有一个相对较小的，次区域域。然后，我们得到详细的估计CHBr 3排放量在这一领域内，这似乎是相对不敏感的反转过程中固有的假设。我们推断这一信息，以产生估计的排放量为整个热带地区（定义为20度S-20度N）的225千兆克CHBr 3年（-1）。我们推断所依据的区域的海洋通常比热带平均水平要浅一些，生物生产力更高。尽管如此，我们的热带估计低于最近的大多数其他研究，并表明海岸线丰富的海洋大陆的CHBr 3排放量可能不会比热带其他地区的排放量更强。
Bromine plays an important role in ozone chemistry in both the troposphere and stratosphere. When measured by mass, bromoform (CHBr3) is thought to be the largest organic source of bromine to the atmosphere. While seaweed and phytoplankton are known to be dominant sources, the size and the geographical distribution of CHBr3 emissions remains uncertain. Particularly little is known about emissions from the Maritime Continent, which have usually been assumed to be large, and which appear to be especially likely to reach the stratosphere. In this study we aim to reduce this uncertainty by combining the first multi-annual set of CHBr3 measurements from this region, and an inversion process, to investigate systematically the distribution and magnitude of CHBr3 emissions. The novelty of our approach lies in the application of the inversion method to CHBr3. We find that local measurements of a short-lived gas like CHBr3 can be used to constrain emissions from only a relatively small, sub-regional domain. We then obtain detailed estimates of CHBr3 emissions within this area, which appear to be relatively insensitive to the assumptions inherent in the inversion process. We extrapolate this information to produce estimated emissions for the entire tropics (defined as 20 degrees S-20 degrees N) of 225 Gg CHBr3 yr(-1). The ocean in the area we base our extrapolations upon is typically somewhat shallower, and more biologically productive, than the tropical average. Despite this, our tropical estimate is lower than most other recent studies, and suggests that CHBr3 emissions in the coastline-rich Maritime Continent may not be stronger than emissions in other parts of the tropics.