BOWTIE: A ship-based field campaign to explore the inner life of the Atlantic ITCZ

The BOWTIE ship-based field experiment explored the influence of convective storm processes and their oceanic interactions on the Atlantic Inter-Tropical Convergence Zone (ITCZ) in August and September 2024. This research is driven by evidence suggesting that storm-scale dynamics is pivotal for shaping the broader structure of the ITCZ and its connection to global circulation patterns and energy transport. Utilizing the German research vessel METEOR, the expedition involved extensive sampling within the ITCZ from its Northern to Southern edge - while transiting the tropical Atlantic from East to West - with detailed atmospheric and oceanic vertical profiling. The research focuses on obtaining vertically resolved cross-sections of the ITCZ and its surrounding conditions, with an emphasis on the atmosphere-ocean boundary layers. Key measurements include precipitation, cloud and humidity profiles, wind, sea-surface temperature, as well as physical and biogeochemical upper ocean characteristics with state-of-the-art instrumentation. BOWTIE is embedded within the international initiative ORCESTRA that combines eight different sub-campaigns. During BOWTIE the research vessel METEOR also served as a platform for two additional subcampaigns of ORCESTRA, which contributed UAVs (STRINQS) and a dual-polarization C-band radar (CSU’s SEA-POL, through PICCOLO) to the ship’s instrumentation. We will present an overview of BOWTIE and first results from the comprehensive measurments.