AF071018 jules and cable

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Published on January 18, 2008

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The CSIRO Atmosphere Biosphere Land Exchange model (CABLE) - Preliminary JULES results using CABLE’s submodels.:  The CSIRO Atmosphere Biosphere Land Exchange model (CABLE) - Preliminary JULES results using CABLE’s submodels. Eva Kowalczyk, Yingping Wang and Rachel Law CSIRO Marine and Atmospheric Research Kowalczyk et al., CMAR Research Paper 013, 2006. Cape Grim Tumbarumba Slide2:  Interface to the GCM Canopy radiation; sunlit & shaded visible & near infra-red, albedo stomata transp. & photosynthesis Carbon fluxes; GPP, NPP,NEP SEB & fluxes; for soil-vegetation system: Ef , Hf , Eg , Hg; evapotranspiration soil moisture snow carbon pools; allocation & flow The general structure of CABLE CASA-CNP vegetation dynamics/disturbance soil temp. soil respiration Kowalczyk et al., CMAR Research Paper 013, 2006 Developed at present Future development CABLE ‘s main features:  CABLE ‘s main features - the vegetation is placed above the ground allowing for full aerodynamic and radiative interaction between vegetation and the ground. The plant turbulence model by Raupach et al. (1997) - a coupled model of stomatal conductance, photosynthesis and the partitioning of absorbed net radiation into latent and sensible heat fluxes. - the model differentiates between sunlit and shaded leaves  i.e. two-big-leaf sub-models for calculation of photosynthesis, conductance and leaf temperature - the radiation submodel calculates the absorption of beam and diffuse radiation in visible and near infrared wavebands, and thermal radiation - a multilayer soil model is used; Richards equations are solved for soil moisture and heat conduction equation for soil temperature - the snow model computes temperature, density and thickness of three snowpack layers.  At present we are developing a terrestrial biogeochemical model for carbon, nitrogen and phosphorus including symbiotic nitrogen fixation ( Wang, Houlton and Field,2007). Slide4:  Canopy representation in “big leaf” models and CABLE Hf Hf H= δf Hf + (1 – δf )Hg H= Hf + Hg δf Coupled model of stomatal conductance and photosynthesis:  Coupled model of stomatal conductance and photosynthesis The two-leaf model ( sunlit & shaded ) of Wang & Leuning [1998] is used to calculate 6 variables: Tf - leaf temperature Ds - vapour pressure deficit Cs - CO2 concentration at the leaf surface Ci - intercellular CO2 concentration of the leaf Gs - stomatal conducatnce An - net photosynthesis The set of six equations is used to solve simultaneously for photosynthesis, transpiration, sensible heat flux and leaf temperature of sunlit and shaded leaves. Slide6:  Fast biophysical processes Canopy conductance photosynthesis, leaf respiration Carbon transfer, Soil temp. & moisture availibity Slow biogeographical processes Vegetation dynamics & disturbance Land-use and land-cover change Vegetation change Autotrophic and Heterotrophic respiration Allocation Intermediate timescale biogeochemical processes Phenology Turnover Nutrient cycle Solution of SEB; canopy and ground temperatures and fluxes Soil heat and moisture Surface water balance Update LAI, Photosyn-thesis capacity Physical-chemical forcing T,u,Pr,q, Rs,Rl, CO2 Radiation water, heat, & CO2 fluxes days years Biogeo- chemical forcing Time scale of biosphere-atmosphere interactions Atmosphere minutes Slide7:  Preliminary JULES’ results using CABLE’s submodels: - snow ( with JULES’ grid soil under ) - soil moisture ( tiles ) - soil temperature ( tiles ) CABLE JULES :  CABLE JULES Snow depth simulations for three tiles; JULES JULES with CABLE’s snow:  Snow depth simulations for three tiles; JULES JULES with CABLE’s snow Forest tile Grass tile Bare ground tile Soil temperatures Snow simulations - JULES/CABLE:  Snow simulations - JULES/CABLE Snow density of 3-layer snowpack Snow mass and albedo Skin temperature :  Skin temperature Skin temperature for Jules only simulation Skin temperature is lower in Jules/Cable simulation Tiled subsurface – soil temperature:  Tiled subsurface – soil temperature Forest tile Grass tile Bare ground tile Grid mean soil temperature Green - latent heat flux Red – sensible heat flux Time series of latent and sensible heat fluxes Grid mean latent and sensible fluxes Tiled subsurface – soil moisture:  Tiled subsurface – soil moisture Grass tile Bare ground tile Forest tile Grid mean soil moisture Time series of latent and sensible heat fluxes Green - latent heat flux Red – sensible heat flux Grid mean latent and sensible fluxes Tiled versus Grid simulation :  Tiled versus Grid simulation Simulation for semi-arid conditions shows larger latent heat flux from ‘grid’ than ‘tile’ run Next steps:  Next steps Couple CABLE to UM model Model development New carbon pools and soil respiration. Inclusion of nitrogen and phosphorus cycle Include more elaborate phenology – timing of onset and cessation of photosynthesis Water and carbon isotopes Include interactive leaf area index (LAI) Systematic method for determining model parameters Thank you:  Thank you Contact Name: Eva Kowalczyk Phone: (61 3 9239 4524) Email: eva.kowalczyk@csiro.au Web: www.cmar.csiro.au Cape Grim Tumbarumba

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