ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. 1866-3591 Göttingen, Germany 10.5194/essd-2026-343 BOWTIE: ship-based measurements of atmosphere and ocean within the moist tropical Atlantic Segura Hans https://orcid.org/0000-0002-6720-5882 1 Wing Allison A. https://orcid.org/0000-0003-2194-8709 2 Kalesse-Los Heike https://orcid.org/0000-0001-6699-7040 3 Carrasco Ruben 4 Ruppert Jr. James H. https://orcid.org/0000-0001-5235-9718 5 Trosits Anna https://orcid.org/0009-0000-5303-0332 3 6 Nuijens Louise 7 Ament Felix 8 Blandfort Daniel 4 Bell Michael M. https://orcid.org/0000-0002-0496-331X 9 Bosser Pierre https://orcid.org/0000-0001-5439-9860 10 Colón-Burgos Delián 9 George Geet https://orcid.org/0000-0002-1579-4523 7 Habib Joelle https://orcid.org/0000-0001-9604-7927 11 Horstmann Jochen 4 Jansen Friedhelm 1 Kluft Lukas https://orcid.org/0000-0002-6533-3928 1 Kopte Robert 12 Möller Klas Ove https://orcid.org/0000-0003-3118-2161 4 Paschou Peristera https://orcid.org/0000-0001-9959-0247 13 Schmidt Hauke https://orcid.org/0000-0001-7977-5041 1 Schlundt Michael 14 Serikov Ilya 1 Stelzner Martin 15 Thompson Elizabeth J. https://orcid.org/0000-0002-0131-4170 16 Wimmer Werenfrid 17 Dengler Marcus https://orcid.org/0000-0001-5993-9088 14 Klocke Daniel 1 Max-Planck-Institut für Meteorologie, Hamburg, Germany Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA Universität Leipzig, Leipzig, Germany Helmholtz-Zentrum Hereon, Geesthacht, Germany School of Meteorology, University of Oklahoma, Norman, OK, USA ETH Zürich, Zürich, Switzerland Delft University of Technology, Netherlands Universität Hamburg, Hamburg, Germany Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA Lab-STICC/M3 UMR 6285 CNRS, ENSTA, IP Paris, Brest, France Laboratoire d’Océanographie de Villefranche, France Institute of Geosciences, Kiel University, Kiel, Germany Institute of Astronomy, Astrophysics, Space Applications & Remote Sensing (IAASARS), National Observatory of Athens, Athens, Greece GEOMAR Helmholtz-Zentrum für Ozeanforschung, Kiel, Germany Deutscher Wetterdienst, Hamburg, Germany National Oceanic and Atmospheric Administration Physical Sciences Lab, Boulder, USA University of Southampton, Southampton, United Kingdom 16 07 2026 2026 1 53 Copyright: © 2026 Hans Segura et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://essd.copernicus.org/preprints/essd-2026-343/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2026-343/essd-2026-343.pdf

As part of BOWTIE (German: Beobachtung von Ozean und Wolken - Das Trans ITCZ Experiment), the German research vessel <em>FS Meteor</em> navigated the moist tropics of the Atlantic Ocean for 40 days in summer 2024, with an east-west trajectory. The journey started in the port of Mindelo, Cape Verde, on August 16, and finished in the port of Bridgetown, Barbados, on September 24. The objective was to measure properties of the atmosphere, upper-ocean, and air-sea interface within the Intertropical Convergence Zone (ITCZ), under a variety of wind, convection, and sea surface temperature regimes. Using a set of 29 instruments/platforms, BOWTIE sampled the near-surface conditions of the atmosphere and ocean with high temporal resolution. This included continuous measurements of: the 2-D wind field within the lowest 2 km of the atmosphere, near-surface ocean currents, cloud and precipitation properties. Profiles of the ocean state and atmospheric thermodynamics and kinematics were obtained both continuously and at discrete intervals. Furthermore, dedicated stations sampled biochemical properties of the upper-ocean. Complementing BOWTIE observations, <em>FS Meteor</em> hosted further dedicated field campaigns for 3D cloud and precipitation properties, as well as intensive measurements of the atmospheric boundary layer. This manuscript provides an overview of the extensive instrumentation and data collected during BOWTIE. In addition, it addresses two key aspects based on these observations. First, it examines the range and uncertainties of selected quantities measured by multiple instruments, including column-integrated water vapor, rain detection, surface ocean currents, and sea surface temperature. Second, it illustrates the diversity of sampled weather regimes through two representative cases: calm doldrum conditions and a gusty, precipitating convective state.