Shipboard Measurements of DMS and SO2 in ASTEX

为参加一项国际海洋大气化学实验，提出了一套七项提案和两项补充请求。1992年6月北大西洋东部的大西洋层积云过渡是一项多国努力，旨在提高我们研究云化学相互作用和影响它们的空气/海洋通量的能力。ASTEX的MAGE大气化学实验的具体目标包括：1)开发和测试拉格朗日策略，用于研究标记气团中的化学和气象演变，使用船只、气球和飞机；2)通过与传统方法的比较，开发和测试估算空气/海洋界面上痕量气体和气溶胶通量的新技术；3)评估海洋和大陆气溶胶的影响以及层积云的形成和消散；4)比较自然和人为的硫、卤素和碳氢化合物对海洋气溶胶化学的影响；5)使用多国、多机构的实地实验作为解决对流层化学问题的手段。在这项MAGE提案中，pi建议在ASTEX研究区域内对海水中的二甲硫醚（DMS）和船上空气中的二氧化硫和DMS进行测量。主要目的是确定在拉格朗日实验中沿着包裹取样轨迹的海洋中DMS的含量。他们提出用薄膜模型计算包裹轨迹上的DMS通量。然后，DMS通量数据将用于减少拉格朗日预算分析中的变量数量，或用于检验直接从预算分析中获得的DMS通量数据的可靠性。次要目标包括空气包裹经过船舶前后空气中的DMS和二氧化硫的测定。这些数据将提供有关气流包的上、下风向的DMS和二氧化硫水平变化的信息。这些测量结果将与从飞机平台获得的结果相辅相成，因为在拉格朗日实验中，飞机不会对完全相同的空气包裹进行采样。PIs还建议获得足够的数据来表征DMS和二氧化硫的日变化，以帮助测试海洋边界层的化学模型。

A set of seven proposals and two supplement requests was submitted for participation in an international marine atmospheric chemistry experiment. The Atlantic Stratocumulus Transition in the eastern North Atlantic during June 1992, is a multinational effort designed to improve our capability for studying cloud-chemistry interactions and the air/sea fluxes that affect them. The specific goals of the MAGE atmospheric chemistry experiment in ASTEX include: 1) develop and test a Lagrangian strategy for studying chemical and meteorological evolution in a tagged airmass, using ships, balloons, and aircraft; 2) develop and test new techniques for estimating trace-gas and aerosol fluxes across the air/sea interface by comparison with traditional approaches; 3) evaluate the impact of marine and continental aerosols and the formation and dissipation of stratocumulus clouds; 4) compare the impacts of natural and anthropogenic sulfur, halogens, and hydrocarbons on marine aerosol chemistry; and 5) use a multinational, multi-agency field experiment as a means for addressing tropospheric chemistry issues. In this MAGE proposal, the PIs propose to conduct measurements of dimethyl sulfide (DMS) in ocean water and sulfur dioxide and DMS in air from shipboard in the study area of ASTEX. The primary objective is to determine the DMS content in the ocean along the track of the parcel sampled in a Lagrangian experiment. The PIs propose to compute the DMS flux along the parcel trajectory using a thin film model. Then, the DMS flux data would be used to reduce the number of variables in the Lagrangian budget analysis or to test the reliability of DMS flux data obtained directly from the budget analysis. Secondary objectives include the determination of DMS and sulfur dioxide in air before and after the air parcel passes over the ship. These data would provide information on the horizontal variation of DMS and sulfur dioxide upwind and downwind of the air parcel. These measurements would compliment those obtained from an aircraft platform because the aircraft will not sample exactly the same air parcel during the Lagrangian experiment. The PIs also propose to obtain sufficient data to characterize the diurnal variation of DMS and sulfur dioxide to aid in testing chemical models of the marine boundary layer.