# Creating a Regional MODIS Satellite-Driven Net Primary Production Dataset for European Forests
## 3 Results
### NPP Estimates across Different Scales  
Comparing all our three NPP estimates on a European scale allowed us to explore the general behaviour and evaluate the agreement of the two remote sensing driven NPP products, MODIS GLOB and MODIS EURO, with the terrestrial driven NFI NPP estimates (Figure 3). Re-running the MOD17 algorithm with local climate data reduced the remotely sensed MODIS NPP in terms of median, mean and variation as compared to the global climate driver (Figure 3). NFI NPP is close to MODIS EURO regarding median and mean, but show larger variation. In addition, Figure 3 confirms that our data is clearly right-skewed (NFI NPP in particular). Zooming in and examining the different NPP estimates by ecoregion and country allowed us to analyze our results on a higher spatial resolution and to assess local effects such as different regional growing conditions, the impact of local biomass allometries or tree species composition [32] as well as the potential effect of different forest management practices in Europe [7]. We provide in Table 2 the median NPP for the three NPP sources (MODIS GLOB, MODIS EURO and NFI NPP) and the differences between MODIS and NFI NPP (\(\Delta\)NPP\({}_{\text{GLOB}}\) and \(\Delta\)NPP\({}_{\text{EURO}}\)), both in absolute values in gC\(\cdot\)m\({}^{-2}\cdot\)year\({}^{-1}\) and normalized in relation to NFI NPP (Rel. \(\Delta\)NPPi in %). Results are given in Table 2 for Europe, by country and for the four eco-regions [7]. At the European level, the MODIS GLOB gives an NPP of 680 gC\(\cdot\)m\({}^{-2}\cdot\)year\({}^{-1}\), the MODIS EURO resulted in 577 gC\(\cdot\)m\({}^{-2}\cdot\)year\({}^{-1}\), and the NPP from the NFI data exhibit a value of 539 gC\(\cdot\)m\({}^{-2}\cdot\)year\({}^{-1}\). The differences in NPP (\(\Delta\)NPP\({}_{\text{GLOB}}\)) using the global dataset MODIS GLOB are larger than \(\Delta\)NPP\({}_{\text{EURO}}\) using the regional dataset MODIS EURO (+26% vs. +7%). The same pattern is evident across all four \begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**NPP and \(\Delta\)NPP (gC\(\cdot\)m\({}^{-2}\cdot\)year\({}^{-1}\))** & **MODIS** & **MODIS** & & & \(\Delta\)**NPP** & & **Rel. \(\Delta\)NPP [\%]** \\ \hline \multirow{6}{*}{North Europe} & \multirow{2}{*}{**GLOB**} & **EURO** & **NFI NPP** & **GLOB** & **EURO** & **GLOB** & **EURO** \\ \cline{3-10}  & & **All Countries** & **680** & **577** & **539** & **141** & **38** & **26\%** & **7\%** \\ \cline{2-10}  & Finland & 471 & 399 & 414 & 57 & \(-15\) & 14\% & \(-4\%\) \\  & Norway & 484 & 406 & 409 & 75 & \(-3\) & 18\% & \(-1\%\) \\  & Estonia & 534 & 504 & 492 & 42 & 12 & 9\% & 3\% \\  & all & 519 & 479 & 461 & 58 & 18 & 13\% & 4\% \\ \hline \multirow{6}{*}{Central-West Europe} & Austria & 739 & 612 & 634 & 105 & \(-22\) & 17\% & \(-4\%\) \\  & Belgium & 732 & 599 & 644 & 88 & \(-45\) & 14\% & \(-7\%\) \\ \cline{1-1}  & France & 787 & 666 & 604 & 183 & 62 & 30\% & 10\% \\ \cline{1-1}  & Germany & 692 & 602 & 716 & \(-24\) & \(-114\) & \(-3\%\) & \(-16\%\) \\ \cline{1-1}  & all & 759 & 645 & 615 & 144 & 30 & 23\% & 5\% \\ \hline \multirow{6}{*}{Central-East Europe} & Czech & \multirow{2}{*}{696} & 618 & 553 & 143 & 65 & 26\% & 12\% \\  & Republic & 641 & 571 & 659 & \(-19\) & \(-88\) & \(-3\%\) & \(-13\%\) \\ \cline{1-1}  & Poland & 713 & 562 & 565 & 148 & \(-3\) & 26\% & \(-1\%\) \\ \cline{1-1}  & all & 677 & 592 & 595 & 82 & \(-3\) & 14\% & \(-1\%\) \\ \hline \multirow{6}{*}{South Europe} & Italy & 862 & 657 & 635 & 227 & 22 & 36\% & 4\% \\ \cline{1-1}  & Spain & 632 & 555 & 503 & 129 & 52 & 26\% & 10\% \\ \cline{1-1}  & all & 691 & 584 & 519 & 172 & 65 & 33\% & 13\% \\ \hline \end{tabular}
\end{table} 
Table 2: NPP and \(\Delta\)NPP (always using median) for the whole dataset (“All Countries”), for each country separately and for each region (MODIS NPP using global climate data—MODIS GLOB; MODIS NPP using local European climate data—MODIS EURO and NPP using forest inventory data—NFI NPP); \(\Delta\)NPP and Rel. \(\Delta\)NPP both for MODIS GLOB and MODIS EURO.