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上风上方的海洋边界层(MBL)测量气相过氧化氢和甲基过氧化氢。PASE是将于2007年8月至9月在NSF/NCAR C-130飞机上对遥远的海洋对流层下部的海洋硫化学进行的综合研究。与佐治亚理工学院的模拟工作合作，将实施一种化学机制，包括大量气溶胶化学、云滴、气相化学以及参数化气-气-气溶胶质量传输和自由对流层-MBL与大气-海洋表面之间的物质通量，以分析和解释过氧化氢数据。该机制将包括卤素，特别是溴。在Pase过程中，硫物种预计将受到来自海洋的二甲基硫化物(DMS)通量及其随后的氧化的调节。对于理解海洋硫磺气体对新粒子产生、粒子生长、云凝结核和气候的影响，关键是DMS中二氧化硫、二甲基亚砜和硫酸盐的产生和去向。过氧化氢是硫化物的重要云内氧化剂。过氧化氢的PASE测量和建模将限制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。这项工作还将限制可疑的氧化剂，如溴一氧化碳(Bro)，这是赤道太平洋中一种潜在的重要DMS氧化剂，处于预期(0.05-0.5ppt)但目前无法测量的水平。这项研究的广泛影响包括研究生的教育和培训，本科生接触大气化学研究，以及传播大气化学、海洋气溶胶和气候的新知识。知识转让将通过出版物和向其他科学家和普通公众发表演讲的方式进行。

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.