Pacific Atmospheric Sulfur Experiment

太平洋大气硫实验（PASE）是将于2007年8 - 9月在圣诞岛（Kiritimati）附近进行的一项对遥远海洋对流层中硫的化学和物理的综合研究。PASE将重点研究无云对流边界层（CBL）和缓冲层中的气相化学、气溶胶组成和生长，以及海洋积云流出云中新颗粒的形成。来自海洋的二甲基硫化物（DMS）通量是远端海洋大气中硫的主要来源，DMS氧化产物在气溶胶的形成和生长中起重要作用。除了反射入射的太阳辐射（直接效应）外，气溶胶还改变云的形成和性质（间接效应），这是气候和全球变化中最不确定的过程之一。PASE将为发展对该地区气溶胶间接影响的了解提供必要的信息。NSF C-130飞机上最先进的仪器将用于对二氧化硫（SO2）、DMS、二甲基亚砜、二甲砜、甲烷磺酸、羟基自由基、氨、水蒸气（H2O）、臭氧（O3）、过氧化氢、气溶胶大小分布和组成以及气象参数进行准确和高速的机载测定。DMS, SO2， H2O和O3将在25 Hz下测量，允许通过涡流相关来确定这些物种的垂直通量。硫的化学收支可以通过它们的浓度和通量来计算。这些预算将包含关于化学的一般资料，特别是关于化学形成和损失率的宝贵资料。PASE是对地球辐射收支和气候变化中气溶胶强迫的化学基础的研究。PI将尝试通过在费城自然科学院的公开演讲，通过新闻媒体，以及在高中巡回演讲来传达这一点。将在德雷塞尔大学建立一个网页，向公众提供PASE的目标和结果。更广泛的影响还包括来自德雷塞尔大学、佐治亚理工学院、加州大学戴维斯分校、沙漠研究所/内华达大学和夏威夷大学的本科生和研究生的参与，他们将协助项目的实地阶段，并参与数据解释、数据存档和结果报告。

The Pacific Atmospheric Sulfur Experiment (PASE) is a comprehensive study of the chemistry and physics of sulfur in the remote marine troposphere that will take place near Christmas Island (Kiritimati) in August-September 2007. PASE will focus on gas-phase chemistry, and aerosol composition and growth, in the cloud-free convective boundary layer (CBL), as well as the buffer layer, and the formation of new particles in the cloud outflow of marine cumulus. The flux of dimethyl sulfide (DMS) from the ocean is the major source of sulfur to the remote marine atmosphere and DMS oxidation products are important in aerosol formation and growth. In addition to reflecting incoming solar radiation (the direct effect), aerosols also alter the formation and properties of clouds (indirect effects), which are among the most uncertain processes in climate and global change. PASE will provide information essential for developing an understanding of the aerosol indirect effect in this region. State-of-the-art instrumentation on the NSF C-130 aircraft will be used to make accurate and high speed airborne determinations of sulfur dioxide (SO2), DMS, dimethyl sulfoxide, dimethyl sulfone, methane sulfonic acid, hydroxyl radical, ammonia, water vapor (H2O), ozone (O3), hydrogen peroxide, aerosol size distributions and composition, and meteorological parameters. DMS, SO2, H2O and O3 will be measured at 25 Hz, allowing vertical fluxes of these species to be determined by eddy correlation. Chemical budgets for the sulfur species can be calculated from their concentrations and fluxes. These budgets will contain valuable information on chemistry in general, and on chemical formation and loss rates in particular. PASE is a study of the chemistry underlying aerosol forcing in earth's radiation budget and climate change. The PI will attempt to communicate this through public presentations at the Academy of Natural Sciences in Philadelphia, through the news media, and on a speaker tour to high schools. A web page will be maintained at Drexel University that provides access to the goals and results of PASE for the public. Broader impacts also include the participation of undergraduate and graduate students from Drexel, Georgia Institute of Technology, University of California, Davis, Desert Research Institute/University of Nevada, and the University of Hawaii, who will assist with the field phase of the program and participate in data interpretation, data archiving, and reporting of results.