Abstract
The interest in the development and improvement of the dynamic global vegetation models (DGVMs), which have the potential to simulate fluxes of carbon, water and nitrogen, and vegetation dynamics in an integrated system has been increasing. In this paper, some numerical schemes and a higher resolution soil texture dataset are employed to improve the Sheffield Dynamic Global Vegetation Model
(SDGVM). Using the eddy covariance-based measurements, we then test the standard version of the SDGVM and the modified version of the SDGVM. Detailed observations of daily carbon and water fluxes made at the upland oak forest on the Walker Branch Watershed in Tennessee, USA offered a unique opportunity for these comparisons. The results revealed that, the modified version of the SDGVM did a
reasonable job of simulating the carbon flux, water flux and the variation of soil water content. However, at the end of the growing season, it failed to simulate the dynamics of limitations on the soil respiration and as a result underestimated the soil respiration. It was also noted that the modified version overestimated the increase in soil water content following summer rainfall, which was attributed to an inadequate representation of the ground water and thermal cycle.
