SGER: Reactive Halogen Detection in the Marine Boundary Layer Using Atmospheric Pressure Ionization/Chemical Ionization Mass Spectrometer (API/CIMS)

这一探索性研究小额赠款(SGER)项目涉及2004年春季和初夏在北太平洋地区的一艘研究游轮(R/V Wecoma)上部署一台新开发的仪器。这艘机遇号邮轮从关岛经夏威夷前往俄勒冈州，致力于了解海洋和大气之间的有机卤化物交换。该项目将包括首次测量公海上的二卤素气体，氯(Cl2)、溴(Br2)、碘(I2)、溴氯(BrCL)和碘氯(ICL)。这种测量方法是基于大气压化学电离质谱仪(API/CIMS)的，其他研究人员已经证明其变体对大气痕量组分具有极高的灵敏度和选择性。这些首批测量如果成功，将提供关于这些气体对海洋边界层中臭氧、碳氢化合物和硫化物化学影响的宝贵信息，并可能极大地改变我们对这一区域大气光化学的理解。第二个甚至是更具探索性的测量涉及对卤素氧化物、ClO和BrO的量化，使用化学转化为可由API/CIM测量的物种(氢化卤代丙酮)。这项研究的更广泛影响包括为两名研究生和一名博士后提供实地研究经验。此外，这项研究有助于理解海洋大气边界层的组成，并为这些气体与海洋表层的交换提供限制，从而有助于实现表面海洋低层大气研究(SOLAS)计划的目标。从长远来看，这项研究将提高对海洋边界层中作用的氧化过程的理解，从而将更好地限制对地球气候重要的气体的命运和寿命。

This Small Grants for Exploratory Research (SGER) project involves the deployment of a newly developed instrument aboard a research cruise vessel (R/V Wecoma) in the North Pacific Ocean region in the spring and early summer of 2004. This cruise of opportunity, from Guam to Oregon via Hawaii, is dedicated to understanding the exchange of organic halogen compounds between the ocean and the atmosphere. This project will involve first measurements of the dihalogen gases, chlorine (Cl2), bromine (Br2), iodine (I2), bromochlorine (BrCl), and iodochlorine (ICl), over the open ocean. The measurement method is based on atmospheric pressure chemical ionization mass spectrometry (API/CIMS), variants of which have been demonstrated by other researchers to be extremely sensitive and selective for atmospheric trace components. These first measurements, if successful, will provide valuable information on the role of these gases impact on the chemistry of ozone, hydrocarbons and sulfur compounds in the marine boundary layer, and could substantially revise our understanding of atmospheric photochemistry in this region. A second, even more exploratory measurement involves the quantification of the halogen oxides, ClO and BrO, using chemical conversion to species (deuterated haloacetones) that can be measured by API/CIMS.The broader impacts of this research include providing field research experience for two graduate students and one post-doctoral fellow. In addition, this research contributes to the goals of the Surface Ocean Lower Atmosphere Study (SOLAS) program by helping to understand the composition of the marine atmospheric boundary layer and provide constraints on exchange of these gases with the ocean surface layer. In the longer view, this research will improve understanding of the oxidation processes operative in the marine boundary layer, and thus will better constrain the fate and lifetime of gases important for the earth's climate.