Oceanic Reactive Carbon: Chemistry-Climate impacts (ORC3)

海洋活性碳：化学-气候影响 (ORC3)

• 批准号: NE/K004980/1
• 负责人: Lucy Carpenter
• 金额: $ 23.79万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK004980%2F1
• 关键词: Oceanic; Reactive; Carbon; Chemistry; Climate

Oceanic organic carbon (OC) aerosol particles have been proposed to exert a profound effect on climate through modification of the properties of shallow marine stratocumulus clouds, yet their sources are highly uncertain. These aerosol may be generated directly by sea spray involving a bubble bursting mechanism, or by the emission and subsequent oxidation of biogenic VOC (BVOC) that produce semivolatile products and aerosol. There is evidence that the secondary component of marine OC is underpredicted by our current models. Oceanic terpenes, especially isoprene and the monoterpenes, are highly reactive BVOC produced by phytoplankton, and are prime candidates for secondary organic aerosol (SOA). Limited observations show high concentrations of these species over biologically active regions of the remote marine atmosphere, which implies that they may play a role in modifying marine cloud properties through SOA formation. A clear picture of the contribution of marine terpenes to SOA is hampered by a lack of observations in the remote MBL. Substantial differences exist between "bottom-up" methods of estimating global emissions, where lab-based photoplankton production rates are scaled to the global oceans, and "top-down" estimates, where the source is scaled to force a match between modelled and observed atmospheric concentrations. The bottom-up methods are generally a factor of 10-1000 smaller than top-down methods, suggesting that they do not capture the full range of marine processes giving rise to BVOC production. The much higher top-down estimates however are also subject to significant uncertainty since they are derived from only a limited quantity of concentration measurements in the MBL. Our preliminary model results suggest that a global monoterpene source of the magnitude required to reproduce observed marine concentrations may increase the aerosol number acting as cloud condensation nuclei (CCN) by up to a factor of two over large oceanic regions. This has profound significance for our understanding of the first aerosol indirect effect, since it alters our understanding of controls on the background natural aerosol. In addition, marine terpenes are highly reactive, and therefore may alter the atmospheric oxidising capacity (and therefore the lifetime of the greenhouse gas methane), especially in the marine tropics where most methane is destroyed. Another potential source of marine SOA is glyoxal, a highly reactive species which has been observed in the remote atmosphere many 1000s km away from the coasts. This species has a lifetime on the order of hours and so transport from terrestrial sources cannot explain its presence in the remote marine atmosphere. Oxidation of glyoxal leads to the rapid production of peroxy radicals and condensable products which are believed to lead to the formation of SOA. However the presence of glyoxal in remote marine regions is so far unexplained. One as yet unexplored hypothesis is photo-oxidation of larger VOCs such as terpenes. The implications of a large marine glyoxal source for atmospheric composition and climate has also yet to be tested.In this project we will substantially increase the observational database of monoterpenes and isoprene in the marine atmosphere and evaluate existing and make new observations of glyoxal. We will use these observations along with global models of chemistry and aerosol to quantify the impact of marine reactive oceanic carbon on atmospheric composition and climate.Improved understanding of natural processes controlling background aerosol and atmospheric oxidative capacity in the Earth's climate system is of high priority, since they underpin our estimates of man-made impacts on climate and the Earth system response. There is an urgent need to evaluate the marine sources of reactive volatile organic compounds (VOCs) and to quantity their importance for CCN, oxidative capacity and global climate.

海洋有机碳（OC）气溶胶粒子被认为通过改变浅海层积云的性质对气候产生深远的影响，但其来源尚不确定。这些气溶胶可能直接由涉及气泡破裂机制的海水喷雾产生，或由产生半挥发性产物和气溶胶的生物挥发性有机化合物（BVOC）的排放和随后的氧化产生。有证据表明，我们目前的模型低估了海洋OC的次要成分。海洋萜烯，特别是异戊二烯和单萜烯，是由浮游植物产生的高活性BVOC，是二次有机气溶胶（SOA）的主要候选者。有限的观测表明，这些物种的高浓度的生物活性区域的远程海洋大气，这意味着他们可能会发挥作用，通过SOA的形成修改海洋云的属性。海洋萜烯对SOA的贡献的清晰图像受到缺乏在远程MBL的观测的阻碍。“自下而上”的全球排放量估算方法与“自上而下”的估算方法之间存在很大差异，前者是根据全球海洋的情况对实验室浮游生物的生产率进行估算，而后者是对排放源进行估算，以使模拟的浓度与观测到的大气浓度相匹配。自下而上的方法一般比自上而下的方法小10-1000倍，这表明它们没有涵盖导致BVOC产生的所有海洋过程。然而，更高的自上而下的估计值也存在很大的不确定性，因为它们仅来自于MBL中数量有限的浓度测量值。我们的初步模型结果表明，全球单萜源的规模所需的复制观测到的海洋浓度可能会增加气溶胶的数量作为云凝结核（CCN）的一个因素的两个以上的大型海洋区域。这对我们理解第一个气溶胶间接效应具有深远的意义，因为它改变了我们对背景天然气溶胶控制的理解。此外，海洋萜烯具有高活性，因此可能会改变大气的氧化能力（从而改变温室气体甲烷的寿命），特别是在海洋热带地区，大多数甲烷都被破坏。海洋SOA的另一个潜在来源是乙二醛，这是一种在距离海岸1000公里远的遥远大气中观察到的高活性物质。这一物种的寿命大约为几个小时，因此来自陆地的迁移不能解释其在遥远的海洋大气中的存在。乙二醛的氧化导致过氧自由基和可缩合产物的快速产生，这被认为导致SOA的形成。然而，乙二醛在偏远海洋区域的存在至今无法解释。一个尚未探索的假设是较大的VOC如萜烯的光氧化。大量海洋乙二醛源对大气成分和气候的影响还有待检验，在本项目中，我们将大大增加海洋大气中单萜和异戊二烯的观测数据库，并评估现有的乙二醛观测数据和进行新的观测。我们将利用这些观测结果沿着全球化学和气溶胶模型来量化海洋活性海洋碳对大气成分和气候的影响，提高对控制地球气候系统背景气溶胶和大气氧化能力的自然过程的理解是高度优先的，因为它们支持我们对气候和地球系统响应的人为影响的估计。目前迫切需要评估海洋中活性挥发性有机化合物（VOCs）的来源，并量化其对CCN、氧化能力和全球气候的重要性。

项目成果

Basin-Scale Observations of Monoterpenes in the Arctic and Atlantic Oceans.

• DOI: 10.1021/acs.est.7b02240
• 发表时间: 2017-08
• 期刊: Environmental science & technology
• 影响因子: 11.4
• 作者: S. Hackenberg;S. Andrews;R. Airs;S. Arnold;H. Bouman;D. Cummings;A. Lewis;J. Minaeian;K. M. Reifel;A. Small;G. Tarran;G. Tilstone;L. Carpenter

The Milan Campaign: Studying the Sea Surface Microlayer

米兰战役：研究海面微层

• DOI: 10.1175/bams-d-17-0329.a
• 发表时间: 2020
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: Stolle C

Impact of uncertainties in inorganic chemical rate constants on tropospheric composition and ozone radiative forcing

无机化学速率常数的不确定性对对流层成分和臭氧辐射强迫的影响

• DOI: 10.5194/acp-2017-12
• 发表时间: 2017
• 作者: Newsome B

Technical Note: A fully automated purge and trap GC-MS system for quantification of volatile organic compound (VOC) fluxes between the ocean and atmosphere

技术说明：用于定量海洋和大气之间挥发性有机化合物 (VOC) 通量的全自动吹扫捕集 GC-MS 系统

• DOI: 10.5194/os-11-313-2015
• 发表时间: 2015
• 期刊: Ocean Science
• 影响因子: 3.2
• 作者: Andrews S

A Synthesis Inversion to Constrain Global Emissions of Two Very Short Lived Chlorocarbons: Dichloromethane, and Perchloroethylene

• DOI: 10.1029/2019jd031818
• 发表时间: 2020-06-27
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
• 影响因子: 4.4
• 作者: Claxton, Tom;Hossaini, Ryan;Lunder, Chris
• 通讯作者: Lunder, Chris