A Comprehensive Coupled Model for Tropospheric Halogen Chemistry: Evaluation of Impacts on Tropospheric Ozone, Hydroxyl Radical (OH), and Mercury

对流层卤素化学综合耦合模型：对对流层臭氧、羟基 (OH) 和汞影响的评估

• 批准号: 1643217
• 负责人: Daniel Jacob
• 金额: $ 58.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-10-01 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643217&HistoricalAwards=false
• 关键词: Comprehensive; Coupled; Model; Tropospheric; Halogen

The fate of gaseous emissions is determined by the oxidative capacity of our atmosphere that controls the production of ozone (a criteria pollutant and short lived greenhouse gas), reactive mercury (a toxic pollutant) and the lifetime of methane (a greenhouse gas). The conventional view that hydroxyl radical is the dominant oxidant has been altered by observations that show that halogens (chlorine, bromine and iodine) from natural and anthropogenic sources could also play an critical role as oxidants. However, these processes are not included in current models limiting their ability to predict future impacts. The proposed research will develop a global scale atmospheric chemistry model with this new halogen chemistry that will be evaluated with observations to enable predictions with proper validation and uncertainty quantification.The proposal addresses the role of halogen radical photochemistry on the production of tropospheric ozone (a short lived greenhouse gas), the hydroxyl radical (the major oxidant) and the toxic pollutant Mercury that is uncertain but potentially very important. The research will understand the fundamental mechanisms that cause the outstanding disagreements between observations of key atmospheric oxidants and pollutants and model simulations that limit our ability to predict future changes. To achieve this it will implement a coupled halogen (Cl-Br-I) chemistry photochemical mechanism using existing laboratory measurements within the state-of-the science community GEOS-Chem model framework and evaluate it by the large data sets (from aircraft, ground and space) of atmospheric composition as a function of latitude, longitude, altitude and season that are now available (including from NSF funded airborne field campaigns). This comprehensive model-measurements integration will be used to critically diagnose specific signatures of halogen radicals on ozone, hydroxyl radical and mercury, quantify uncertainties and identify gaps that will enable a new understanding of the role of halogen radicals on tropospheric chemistry to better quantify (1) radiative forcing by ozone, (2) the factors controlling ozone affecting air quality, oxidative capacity and methane lifetime and (3) the impacts of mercury on ecosystems.

气体排放的命运取决于我们大气的氧化能力，它控制着臭氧（一种标准污染物和短寿命温室气体）、活性汞（一种有毒污染物）和甲烷（一种温室气体）的产生。羟基自由基是主要氧化剂的传统观点已经被观察所改变，观察表明来自自然和人为来源的卤素（氯，溴和碘）也可以作为氧化剂发挥关键作用。然而，这些过程没有包括在目前的模型中，限制了它们预测未来影响的能力。建议的研究将利用这种新的卤素化学发展一个全球尺度的大气化学模式，将通过观测进行评估，以便能够进行适当验证和不确定性量化的预测。建议涉及卤素自由基光化学在对流层臭氧产生中的作用（一种短暂的温室气体）、羟基自由基（主要氧化剂）和有毒污染物汞（不确定但可能非常重要）。该研究将了解导致关键大气氧化剂和污染物的观测与模型模拟之间存在显著差异的基本机制，这些差异限制了我们预测未来变化的能力。为实现这一目标，它将利用科学界最先进的全球测地系统-化学模型框架内现有的实验室测量结果，实施一种耦合卤素（Cl-Br-I）化学光化学机制，并通过现有的（包括来自国家科学基金会资助的空中实地活动的）大气成分随纬度、经度、高度和季节变化的大型数据集（来自飞机、地面和空间）对其进行评估。这一全面的模式-测量综合将用于严格诊断卤素自由基对臭氧、羟基自由基和汞的具体特征，量化不确定性并确定差距，从而能够对卤素自由基对对流层化学的作用有新的认识，以便更好地量化：（1）臭氧的辐射强迫，（2）影响空气质量的控制臭氧的因素，氧化能力和甲烷寿命;（3）汞对生态系统的影响。

项目成果

An Expanded Definition of the Odd Oxygen Family for Tropospheric Ozone Budgets: Implications for Ozone Lifetime and Stratospheric Influence

• DOI: 10.1029/2019gl084486
• 发表时间: 2020-02
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: K. Bates;D. Jacob

A new model mechanism for atmospheric oxidation of isoprene: global effects on oxidants, nitrogen oxides, organic products, and secondary organic aerosol

• DOI: 10.5194/acp-19-9613-2019
• 发表时间: 2019-07-31
• 期刊: ATMOSPHERIC CHEMISTRY AND PHYSICS
• 影响因子: 6.3
• 作者: Bates, Kelvin H.;Jacob, Daniel J.
• 通讯作者: Jacob, Daniel J.

Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere

• DOI: 10.1016/j.atmosenv.2017.02.003
• 发表时间: 2017-04-01
• 期刊: ATMOSPHERIC ENVIRONMENT
• 影响因子: 5
• 作者: Le Breton, Michael;Bannan, Thomas J.;Percival, Carl J.
• 通讯作者: Percival, Carl J.

Effect of sea salt aerosol on tropospheric bromine chemistry

• DOI: 10.5194/acp-19-6497-2019
• 发表时间: 2018-11
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Lei Zhu;D. Jacob;S. Eastham;M. Sulprizio;Xuan Wang;T. Sherwen;M. Evans;Qianjie Chen;B. Alexander;T. Koenig;R. Volkamer;L. G. Huey;M. Breton;T. Bannan;C. Percival

The role of chlorine in global tropospheric chemistry

• DOI: 10.5194/acp-19-3981-2019
• 发表时间: 2019-03
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Xuan Wang;D. Jacob;S. Eastham;M. Sulprizio;Lei Zhu;Qianjie Chen;B. Alexander;T. Sherwen;M. Ev