Variations of Rn/DSR and I/DSR
Figure 3 shows the seasonal variations of Rn /DSR and I /DSR for seven sites representing each of the seven ecosystem types studied. The variations of Rn /DSR were negatively correlated with theI /DSR. In the tropical and subtropical forests, Rn /DSR was higher than I /DSR over the entire year. By contrast, for other ecosystems that are associated with a strong seasonality, Rn /DSR became lower than I /DSR in the winter or non-growing seasons. Accordingly, the difference between Rn /DSR and I /DSR, which is the RI, varied among the different sites with the greatest seen in the tropical rainforest and smallest in the grassland.