Dual gas tracer measurements during the Central Baltic Sea Air-Sea Exchange Experiment (CenBASE)

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。控制大气和海洋之间气体交换的过程在调节全球气候方面起着重要作用，因为它影响大气中温室气体和气溶胶前体的数量。这些物质一旦进入大气，就会影响全球和区域气候。在过去的30年里，在了解远离海岸的开阔海域的这一过程以及风速如何控制这一过程方面取得了重大进展。这些进步主要是由于实验技术的改进，以及在公海上进行的一些成功的科学实验。然而，目前尚不清楚同样的理解是否适用于波罗的海等内陆海。在那里，表面活性剂（一种集中在海面的生物和化学物质）的存在，以及较低的盐度，可能会以不同于开阔海洋的方式影响风对这一过程的影响。在这个项目中，一组调查人员将进行一项实验，旨在评估波罗的海的这些过程，并将其与之前在公海进行的实验进行比较。波罗的海中部海气交换实验（CenBASE）是由美国、英国和德国的科学家合作进行的，目的是在德国研究船Elisabeth Mann Borgeseat上测量波罗的海中部的气体交换率。该提案将为美国科学家提供资金，用于测量用于确定气体交换率的两种气体示踪剂。德国科学家获得独立资助，测量表面活性剂，对二氧化碳和二甲基硫化物进行直接通量测量，对海洋表面的pCO2、CH4、N2O、O2和CO进行连续测量，对水柱中溶解的无机碳、总碱度和pH值进行离散测量。一位英国同事将测量气泡的大小分布。CenBASE的最终目标是确定开阔海域的风速与气体交换之间的关系是否也适用于波罗的海等内海，揭示天然表面活性剂对气体交换的影响，并检验不同测量气体交换的技术是否一致。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The process that controls the exchange of gases between the atmosphere and the ocean plays an important role in regulating global climate, since it influences the amount of atmospheric greenhouse gases and aerosol precursors. Once in the atmosphere, these substances influence global and regional climate. Over the past 30 years, significant advances have been made in understanding this process in the open ocean away from the coasts, and how wind speed controls this process. These advances are mainly due to improvements in experimental techniques, and a number of successful scientific experiments in the open ocean. However, it is not clear if the same understanding applies to inland seas like the Baltic Sea. There, the presence of surfactants, which are biological and chemical substances that concentrate at the sea surface, and the lower salinity, could influence how wind affects this process in a different way than in the open ocean. In this project, a team of investigators will conduct an experiment that aims to assess these processes in the Baltic and compare them to previous experiments in the open ocean.The Central Baltic Sea Air-Sea Exchange Experiment (CenBASE) is a collaboration between scientists from the US, UK, and Germany to measure gas exchange rates in the central Baltic Sea on the German research vessel Elisabeth Mann Borgeseat. This proposal will provide funding to US scientists to make measurements of two gas tracers used to determine the gas exchange rate. German scientists are independently funded to measure surfactants, and make direct flux measurements of carbon dioxide and dimethyl sulfide, as well as make continuous measurements of pCO2, CH4, N2O, O2, and CO in the sea surface, and discrete measurements of dissolved inorganic carbon, total alkalinity, and pH in the water column. A UK colleague will make measurements of bubble size distribution. The ultimate goals of CenBASE are to determine whether the relationship between wind speed and gas exchange in the open ocean also applies to inland seas like the Baltic, shed new light on the effect of natural surfactants on gas exchange, and examine whether different techniques for measuring gas exchange are in agreement.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.