Photosynthesis is computed using a light use efficiency model. The temperature profile is also computed in the upper part of ice sheets and in the ocean shelf soil. Given soil water content, the wetland fraction is computed based on a topographic index. The soil water equation is based on Darcy's law. A surface hydrology module computes precipitation interception by vegetation, surface runoff and soil infiltration. Phase changes of water in the soil are explicitly considered. The soil is vertically discretized into 5 layers where prognostic equations for temperature, water and carbon are consistently solved.
Vegetation and bare soil share a single soil column. Over each surface type the model solves the surface energy balance and computes the fluxes of sensible, latent and ground heat and upward shortwave and longwave radiation.
Including the ocean shelf allows to treat continuous changes in sea level and shelf area associated with glacial cycles. The model distinguishes 9 surface types of which 5 are different vegetation types, bare soil, land ice, lake and ocean shelf. The model explicitly treats permafrost, both in physical processes and as important carbon pool. The model treats in a consistent manner the interaction between atmosphere, terrestrial vegetation and soil through the fluxes of energy, water and carbon. PALADYN is presented, a new comprehensive and computationally efficient land surface–vegetation–carbon cycle model designed to be used in Earth system models of intermediate complexity for long-term simulations and paleoclimate studies.
#Simply fortran Offline
The model description is accompanied by a thorough model evaluation in offline mode for the present day and the historical period. Isotopic discrimination is modelled only during photosynthesis.Ī simple methane module is implemented to represent methane emissions from anaerobic carbon decomposition in wetlands (including peatlands) and flooded ocean shelf. PALADYN includes carbon isotopes 13C and 14C, which are tracked through all carbon pools. The model also includes a dynamic peat module. Carbon buried below ice sheets and on flooded ocean shelves is treated differently. Carbon in permanently frozen layers is assigned a long turnover time which effectively locks carbon in permafrost. For the vegetated macro surface type, decomposition is a function of soil temperature and soil moisture. Carbon can be redistributed between the layers by vertical diffusion and advection. Each soil carbon type has its own soil carbon pools generally represented by a litter, a fast and a slow carbon pool in each soil layer. PALADYN distinguishes between mineral soil carbon, peat carbon, buried carbon and shelf carbon. PALADYN includes a dynamic vegetation module with five plant functional types competing for the grid cell share with their respective net primary productivity. Carbon assimilation by vegetation is coupled to the transpiration of water through stomatal conductance. The soil is vertically discretized into five layers where prognostic equations for temperature, water and carbon are consistently solved. Over each surface type, the model solves the surface energy balance and computes the fluxes of sensible, latent and ground heat and upward shortwave and longwave radiation.
Including the ocean shelf allows the treatment of continuous changes in sea level and shelf area associated with glacial cycles. It distinguishes nine surface types: five different vegetation types, bare soil, land ice, lake and ocean shelf. PALADYN explicitly treats permafrost, both in physical processes and as an important carbon pool. PALADYN is presented it is a new comprehensive and computationally efficient land surface–vegetation–carbon cycle model designed to be used in Earth system models of intermediate complexity for long-term simulations and paleoclimate studies.