Shipboard Measurements of DMS and SO2 in ASTEX

提交了一组七项提案和两项补充请求，要求参加一项国际海洋大气化学实验。1992年6月北大西洋东部的大西洋平流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大气/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，利用船舶、气球和飞机研究标记气团中的化学和气象演变；2)开发和测试与传统方法相比较的新技术，以估计海/气界面上的痕量气体和气溶胶通量；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)利用多国、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建议中，PIS建议在ASTEX研究区域内从船上测量海水中的二甲基硫化物(DMS)和空气中的二氧化硫和DMS。主要目标是确定海洋中DMS含量沿着拉格朗日实验中采样的包裹的轨迹。PI建议使用薄膜模型计算沿包裹轨迹的DMS通量。然后，DMS流量数据将被用来减少拉格朗日预算分析中的变量数量或检验直接从预算分析获得的DMS流量数据的可靠性。次要目标包括测定空气中二甲基硫和二氧化硫在空气包裹经过船舶前后的含量。这些数据将提供关于DMS和二氧化硫在上风向和下风向的水平变化的信息。这些测量将与从飞机平台上获得的测量结果相辅相成，因为在拉格朗日实验期间，飞机不会采样完全相同的气团。物价指数还建议获取足够的数据来描述二甲基硫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.