Seasonal Climatology of Phosphate for Loire River for the period 1964-2019 and for the following seasons:

- winter: January-March,

- spring: April-June,

- summer: July-September,

- autumn: October-December

Observational data span from 1964 to 2019.

Depth levels (m): -125.0, -100.0, -75.0, -50.0,-40.0, -30.0, -25.0, -20.0, -15.0, -10.0, -8.0, -6.0, -4.0, -2.0, -0.0

Data Sources: observational data from SeaDataNet/EMODNet Chemistry Data Network.

Description of DIVAnd analysis: The computation was done with DIVAnd (Data-Interpolating Variational Analysis in n dimensions), version 2.7.4, using GEBCO 30sec topography for the spatial connectivity of water masses. The horizontal resolution of the produced DIVAnd maps grids is 0.01 degrees. Correlation length was optimized and filtered vertically and a seasonally-averaged profile was used. Signal to noise ratio was fixed to 1. Logarithmic transformation applied to the data prior to the analysis. Background field: the data mean value is subtracted from the data. The weight of time series was decreased by a factor of 10 relative to the weight of the profiles to account for the redundancy in the time series observations. Detrending of data: no, Advection constraint applied: no. Units: umol/l.