Black Sea - Danube Delta - DIVAnd 4D seasonal analysis of Water body dissolved inorganic nitrogen 1980/2022 v2025

Water body dissolved inorganic nitrogen - Seasonal Climatology for NW Black Sea (region in front of Danube Delta months) for the period 1980-2019 on the domain: Lon E28.5-30.5°E, Lat N43.7-45.6°N.
Season definition: winter: December-February, - spring: March-May, - summer: June-August, - autumn: September-November.
Units: umol/l.
Data Sources: observational data from SeaDataNet/EMODNet Chemistry Data Network.
Description of DIVA analysis: The computation was done with the DIVAnd (Data-Interpolating Variational Analysis in n dimensions), version 2.7.13, using GEBCO 30sec topography for the spatial connectivity of water masses. Horizontal correlation length of 47.73km and vertical correlation length of 45m were applied.
The horizontal resolution of the produced DIVAnd maps grids is 0.01 degrees.
The vertical resolution is 14 depth levels: 0.0, 2.0, 4.0, 6.0, 8.0, 10.0, 15.0, 20.0, 25.0, 30.0, 40.0, 50.0, 60.0, 70.0 m.
The error variance (epsilon2): 1
An anamorphosis transformation was applied to the data: threshold value=200.
The mean value was used as background analysis field.
Quality control of the observations was applied using the interpolated field: QCMETHOD=3 and visual inspection (Observations with residuals outside the minimum and maximum values of the 99% quantile were discarded from the analysis after thoroughly visual inspection).