The western Mediterranean Sea climatology (BGC-WMED) presented here is a product derived from in situ observations, that included various data sources: in total, 2253 in-situ inorganic nutrient profiles over the period 1981-2017 have been used (Medar/MEDATLAS, Fichaut et al., 2003; the CNR-WMED biogeochemical dataset, Belgacem et al., 2019,2020; SeaDataNet data product, https://www.seadatanet.org; Mediterranean Ocean Observing System for the Environment, MOOSE, http://www.moose-network.fr/). This climatology provides an annual mean gridded nutrient fields for the period 1981-2017, and sub-periods 1981-2004 and 2005-2017, on a horizontal 1/4° × 1/4° grid. The biogeochemical climatology is built on 19 depth levels and for the dissolved inorganic nutrients nitrate, phosphate and orthosilicate. To generate smooth and homogeneous interpolated fields, an advanced N-dimensional version of DIVA, DIVAnd v2.5.1 (Barth et al., 2014), has been used.

Horizontal maps are stored in a NetCDF files for each time period and parameter. Files can be opened with Ncview, Panoply, MATLAB, NcBrowse, etc.Along with the files, there is a README with further file descriptions.---------------------#, ParameterName, Short Name, Comment1, longitude, Lon, Longitude in degrees east, extent: -7 – 17.25 °E2, Latitude, Lat, Latitude in degrees north, extent: 33.5 – 45.85°N3, Depth , depth, Depth in meters, 19 levels, range: 0 – 1500 m4, DIVAnd analyzed climatology , nitrate/ phosphate/silicate, , Mapped climatological fields5, nitrate/phosphate/silicate masked field level 1, nitrate_L1/phosphate_L1/ silicate_L1, Mapped climatological fields masked using relative error threshold 0.3.6, nitrate/phosphate/silicate masked masked field level 2, nitrate_L2/phosphate_L2/ silicate_L2, Mapped climatological fields masked using relative error threshold 0.5.7, nitrate/phosphate/silicate masked relative error, nitrate_relerr/phosphate_relerr/silicate _relerr, Mapped relative error filed associated to the climatological field