Collaborative Research: Peroxide Measurements and Modeling for the Pacific Atmospheric Sulfur Experiment

作为太平洋大气硫实验（PASE）的一部分，将在基里巴斯圣诞岛赤道太平洋逆风上空的海洋边界层（MBL）测量气相过氧化氢和甲基过氧化氢。PASE是在2007年8 - 9月由NSF/NCAR的C-130飞机进行的一项对海洋低空对流层硫化学的综合研究。在与佐治亚理工学院建模工作的合作下，化学机制包括大量气溶胶化学、云滴、气相化学、参数化的气体-气溶胶质量运输和自由对流层- mbl和空气-海洋表面之间的物质通量，将用于分析和解释过氧化氢数据。这种机制将包括卤素，尤其是溴。在PASE期间，硫的种类预计会受到来自海洋的二甲基硫化物（DMS）的通量及其随后的氧化的调节。了解海洋硫气体对新颗粒产生、颗粒生长、云凝结核以及气候的影响的关键是二氧化硫、二甲基亚砜和硫酸盐的产生和命运。过氧化物是一种重要的含硫化合物云内氧化剂。PASE对过氧化物的测量和建模将对气象驱动的物质通量和直接氧化剂（如羟基自由基（OH）和过氧化氢）提供限制。这项工作还将限制可疑的氧化剂，如一氧化二溴（BrO），一种潜在的重要DMS氧化剂，在赤道太平洋的预期水平（0.05-0.5 ppt），但目前无法测量。这项研究的更广泛影响包括研究生的教育和培训，使本科生接触大气化学研究，以及传播关于大气化学、海洋气溶胶和气候的新知识。知识转移将通过出版物和向其他科学家和公众的演讲来实现。

Measurements of gas phase hydrogen peroxide and methylhydroperoxide will be made in the marine boundary layer (MBL) over the equatorial Pacific upwind of Christmas Island, Kiribati, as part of the Pacific Atmospheric Sulfur Experiment (PASE). PASE is a comprehensive study of marine sulfur chemistry in the remote lower marine troposphere to be conducted in August-September 2007 on the NSF/NCAR C-130 aircraft. In collaboration with the Georgia Tech modeling effort, a chemistry mechanism including bulk aerosol chemistry, cloud droplets, gas phase chemistry, and parameterized gas-aerosol mass transport and material fluxes between the free troposphere-MBL and air-ocean surface will be implemented for the analysis and interpretation of the peroxide data. The mechanism will include halogens, bromine in particular. During PASE, sulfur species are expected to be regulated by the flux of dimethylsulfide (DMS) from the ocean and its subsequent oxidation. Critical to understanding the influence of marine sulfur gases on new particle production, particle growth, cloud-condensation nuclei and hence climate, are the production and fate of sulfur dioxide, dimethylsulfoxide, and sulfate from DMS. Peroxides are an important in-cloud oxidant of sulfur compounds. The PASE measurements and modeling of peroxides will provide constraints on meteorologically-driven material fluxes and on direct oxidants such as hydroxyl radical (OH) and hydrogen peroxide. This work will also constrain suspected oxidants like bromine monoxide (BrO), a potentially significant DMS oxidizer in the equatorial Pacific at its expected (0.05-0.5 ppt) but currently unmeasurable levels.Broader impacts of the study include education and training of graduate students, exposure of undergraduates to atmospheric chemistry research, and dissemination of new knowledge on atmospheric chemistry, marine aerosols and climate. Knowledge transfer will occur via publications and presentations to other scientists and the general public.