Coastal pH variability in the Balearic Sea

[Description of methods used for collection/generation of data] In both stations a SAMI-pH (Sunburst Sensors LCC) was attached, at 1 m in the Bay of Palma and at 4 m depth in Cabrera. The pH sensors were measuring pH, in the total scale (pH????T), hourly since December 2018 in the Bay of Palma and since November 2019 in Cabrera. The sensor precision and accuracy are < 0.001 pH and ?? 0.003 pH units, respectively. Monthly maintenance of the sensors was performed including data download and surface cleaning. Temperature and salinity for the Cabrera mooring line was obtained starting November 2019 with a CT SBE37 (Sea-Bird Scientific??). Accuracy of the CT is ?? 0.002 ???C for temperature and ?? 0.003 mS cm???1???1 for conductivity. Additionally, oxygen data from a SBE 63 (Sea-Bird Scientific ??) sensor attached to the CT in Cabrera were used. Accuracy of oxygen sensors is ?? 2%, ?? 1% and ?? 5% for the SBE 63.