Trans-Atlantic aerosol transport from January to March 2025 – measurements from two expeditions on a research vessel

Abstract. Saharan dust outbreaks frequently propagate over the tropical Atlantic, but only few in-situ and ground-based remote sensing observations exist over the region. Here, we document data from EXperiments with the Portable Observatory for aeRosol Transport ("EXPORT") conducted during the expeditions M207 and M208 aboard the German research vessel R/V METEOR. The expedition M207 commenced on January 3, 2025, departing from Belém, Brazil, and concluded in Mindelo, Cabo Verde, on February 11, 2025. Expedition M208 both started and ended in Mindelo, Cabo Verde and lasted from February 15, 2025 until March, 17 2025. Throughout the expeditions, continuous measurements of aerosols and meteorological conditions were carried out. The data collection covers three distinct several-day long Saharan dust events, with the first plume over the tropical mid-Atlantic and the latter two dust plumes closer to the African continent.

Using an optical particle counter (OPC), we measured in-situ concentrations of particulate matter and size distribution information up to a diameter of ∼ 35 μm. We further determined particle size distribution, elemental composition, and deposition rates derived from scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM–EDX). CALITOO and MICROTOPS sun photometers gave aerosol optical depth for several wavelengths. A Vaisala CL61 ceilometer allowed retrievals for fine-scale structure of aerosol layers including depolarization measurements. Moreover, we collected measurements from an optical disdrometer, a broadband radiation sensor, a wind lidar, and almost 90 launches of radiosondes to facilitate improved data interpretation. We here document the collected data sets from EXPORT including first comparison to reanalysis data sets and the ship’s own meteorological sensors. Illustrative examples of the data focus on measurements during the three dust outbreaks over the tropical Atlantic.

The datasets presented in this study are publically available at https://doi.org/10.1594/PANGAEA.983389 (Wahl et al., 2025a), https://doi.org/10.1594/PANGAEA.983348 (Wahl et al., 2025b), https://doi.org/10.1594/PANGAEA.983120 (Wahl et al., 2025c), https://doi.org/10.1594/PANGAEA.995914 (Kanngießer and Wahl, 2026a), https://doi.org/10.1594/PANGAEA.996258 (Wahl and Kanngießer, 2026a), https://doi.org/10.1594/PANGAEA.983118 (Wahl et al., 2025d), https://doi.org/10.1594/PANGAEA.983121 (Wahl et al., 2025e), https://doi.org/10.1594/PANGAEA.988728 (Wahl et al., 2026a), https://doi.org/10.1594/PANGAEA.983119 (Wahl et al., 2025f), https://doi.org/10.1594/PANGAEA.983388 (Wahl et al., 2025g), https://doi.org/10.1594/PANGAEA.983350 (Wahl et al., 2025h), https://doi.org/10.1594/PANGAEA.983128 (Wahl et al., 2025i), https://doi.org/10.1594/PANGAEA.995915 (Kanngießer and Wahl, 2026b), https://doi.org/10.1594/PANGAEA.996259 (Wahl and Kanngießer, 2026b), https://doi.org/10.1594/PANGAEA.983126 (Wahl et al., 2025j), https://doi.org/10.1594/PANGAEA.983129 (Wahl et al., 2025k), https://doi.org/10.1594/PANGAEA.988729 (Wahl et al., 2026b), and dship.o2a-data.de (Universität Hamburg, Meteor, 2025).