Sea Surface Temperature and Directional Wave Spectra During the 2023 Marine Heatwave in the North Atlantic.

In 2023, an unprecedented marine heatwave (MHW) developed in the North Atlantic. MHWs have severe ecological and socioeconomic impacts, and their increasing frequency and intensity demand urgent action from climate scientists and policymakers. The characterisation of MHWs requires high-resolution observations not only of ocean temperature, but also of its physical drivers, such as wind and ocean waves. However, acquiring co-located, in-situ measurements of these variables remains logistically challenging, and data scarcity continues to hinder efforts to fully understand and model MHWs dynamics. Here, a dataset collected by a freely drifting buoy off the west coast of Ireland during the peak of the 2023 MHW event is presented. The dataset includes 1-minute sea surface temperature (SST) and position records, directional wave spectra, wind speed estimates, and derived wave parameters. These data provide a unique opportunity to analyse air-sea interactions during a MHW at fine temporal scales. They are intended to support coupled model validation, diurnal warming studies, and data assimilation efforts, ultimately contributing to improved understanding and forecasting of MHWs.