Incorporating a More Detailed Land Cover Representation into the Sheffield Dynamic Global Vegetation Model
Price, Jennifer; Quaife, Tristan
University of Reading, UNITED KINGDOM
The correct specification of plant functional types (PFTs) in global vegetation models is important in terms of the cycling of carbon and water and also in determining the phenological cycle and surface-atmosphere energy exchanges. The Sheffield Dynamic Global Vegetation Model (SDGVM) uses remotely sensed land cover data products in order to assign the appropriate fractional coverage of plant functional type across the Earth's surface. The product that is currently being used is the GLC2000 which has 22 land cover classes; these are divided between the 7 PFTs used in SDGVM. However there is no distinction between the C3 and C4 photosynthetic pathways in the GLC2000 product, this complicates the assignment of the fractional coverage to these PFTs when SDGVM is run at the global scale. The representation of crops in SDGVM is also currently limited to a single PFT parameterised for temperate cereals. The aim of this work is to incorporate data on the fractional coverage of C4 vegetation around the globe along with an improved representation of different crop types by using literature values to parameterise additional PFTs. In order to quantify the impacts that these changes have on the performance of SDGVM, the monthly outputs of the fraction of photosynthetically active radiation are compared against the observed monthly normalised difference vegetation index data from MODIS.