Verification of Kara Sea primary production models with field and satellite observations

The depth-integrated model (Ψ-Mod) and depth-resolved Kara Sea model (KDRSM) of primary production in the water column were verified using field (2013–2015) and satellite (MODIS-Aqua scanner, 2007, 2011, 2013–2015) observations. The KSDRM and Ψ-Mod over- or underestimate the values of integrated primary production (IPP) in autumn by a factor of 2 and 2.5 with shipboard data as input parameters; the rootmean-square difference (RMSD) was 0.29 and 0.39, respectively. In summer, the efficiency of Ψ-Mod decreased by a factor of 1.5 (RMSD = 0.57), while the predictive capacity of the KSDRM remained the same (RMSD = 0.31). In the Laptev Sea in autumn, the KSDRM performed better than Ψ-Mod (the RMSD was 0.24 and 0.41, respectively). There was no sufficient decrease in the predictive skill of either algorithm when MODIS-Aqua data were used as input parameters. Thus, Ψ-Mod, being a simple and precise algorithm, can be recommended for evaluating the annual IPP in the Kara Sea and for studying its long-term variability using satellite data.