A consistent regional dataset of dissolved oxygen in the Western Mediterranean Sea (2004–2023): O2WMED

Abstract. A new dataset from oceanographic cruises in the Western Mediterranean Sea (WMED) was compiled to integrate the previously published regional data product about dissolved inorganic nutrients CNR-DIN-WMED about dissolved inorganic nutrients (https://doi.org/10.1594/PANGAEA.904172, Belgacem et al., 2019, 2020). The Mediterranean region is experiencing rapid changes, necessitating high-quality and reliable datasets. However, the scarcity of the in-situ observations hinders the understanding of these changes and their impact on biogeochemical cycles. Dissolved oxygen is a vital component of marine ecosystems and plays a fundamental role in governing nutrient and carbon cycles, underscoring the need for accurate and reliable data. To address this, a high resolution, regional-scale data product was developed to understand decadal variability and spatial/temporal patterns of the ventilation process in the WMED. This study presents an extensive collection of unpublished dissolved oxygen data from continuous sensors collected between 2004 and 2023, along with a description of the quality assurance procedures. The quality assurance process involves calibration of CTD measurements against Winkler analyses and the comparison of deep observations with reference datasets, using the crossover analysis. The resulting data product O2WMED can be used as reference for assessing oxygen sensors mounted on biogeochemical Argo (BGC-Argo) floats or Gliders and for regional model validation.