Simulating net primary production and soil-surface CO2 flux of temperate forests in Northeastern China

The Integrated Biosphere Simulator (IBIS) has mainly been applied to simulate carbon and water cycles at large spatio-temporal scales, but has not been localized, validated, and applied in Chinese forests. In this study, we first localized the IBIS to forest regions in Northeastern China, simulated net primary production (NPP) and soil respiration (RS) at stand scales, and validated the simulations with measurements from seven and six representative forest types in this region, respectively. Secondly, we explored spatial patterns of the NPP and RS with the localized model and forest inventory data from 881 sample points and meteorological data from 194 weather stations across the study area. We found that the model simulations of NPP and RS agreed well with the measurements, and the relative error introduced varied with vegetation types and years. The relative difference between simulated and measured values varied from 3.8% to 18.0% for NPP, and from -13% to 16% for RS. The spatial patterns of both NPP and RS showed a significant dependency of the vegetation type, temperature, and precipitation. The study demonstrates that the validated localized IBIS can be applied to simulate spatial and temporal dynamics of NPP and RS in temperate forests at both stand- and regional scales.