Coastal-SMEAR — introduction to infrastructure and capacity of the atmospheric observatory in Tvärminne, Finland

Long-term observations of coastal ecosystems and atmosphere are crucial for addressing global challenges like air pollution, water, energy, and food supply. Coastal environments are ecological hotspots acting as greenhouse gas sinks/sources, emitting volatile organic compounds (VOCs) and trace gases, and impacting marine aerosol formation. The Tvärminne Zoological Station (TZS) in the northern Baltic Sea has a long history of marine biology observations. In 2022, a comprehensive atmospheric observatory was established at TZS, leading to the creation of coastal-SMEAR (Station for Measuring Earth surface – Atmosphere Relations). Equipped with advanced instrumentation, the key aim of this station is to understand potential feedbacks between coastal ecosystems and the atmosphere. Initial results indicate that the sea-air exchange of aerosol precursor gases, VOCs and CO2 at the coast are highly dynamic, influenced by meteorological and biological conditions. Establishing SMEAR stations in different coastal environments would greatly help to understand coastal ecosystem-atmosphere feedbacks.