State of the CLM(ED) model Rosie Fisher & Stefan Muszala Thanks to: Erik Kluzek, Gordon Bonan, Ben Sanderson & Dave Lawrence. CLM(ED) ecosystem demography • Next-generation biogeophysical and biogeochemical core for the CLM! • Landscape structured according to disturbance history.! • Height resolved competition between plants for light. ! • Plant distribution emerges from plant functional properties Recruitment Growth Competition Co-existence Exclusion Te Mortality Science Features ! • Gas exchange (CLM4.5 multi-layer psn; Collatz & Ball-Berry/Medlyn/Lloyd) • Radiation scheme (Norman explicit radiation scheme. Parallel PFTs in discrete canopy layers) • Canopy Structure (Modified Perfect Plasticity Approximation) • Carbon partitioning (Allocation to C storage. Flexible allocation priorities) • Leaf area optimization (Loosely based on Woodward & Lomas 2004 sDGVM) • Mortality (Fisher et al. 2010) • Crown area plasticity (trees change shape as canopy closes) • Phenology (Botta et al. 2001:cold, • SPITFIRE fire scheme (Thonicke, Spessa et al. 2010) • Seed Model (partly from TREEMIG, Lischke et al 2009) • Below ground biogeochemistry (BGC or CN, as before) Dahlin & Fisher, in prep: drought) Tech Note (v0 ready for internal review) 62 pages, 217 equations Timeline • (as of LMWG Feb 2014) Version -1 (EDMERGE branch) Now. Access for development only • Runs in PTCLM & some global resolutions, sensible fluxes, energy + water balanced (afaik), NetCDF restarts • Version 0 (software engineering tag) May.June. Access for adding functionality • NetCDF history files, sensible fluxes, balanced energy/water/carbon, sensible memory use, cold & drought phenology, compsets, runs @ alternative resolutions & compilers. • Version 1 (science tag) Oct.Nov. Access for model testing and implementation • • CLM fire coupling, Soil BGC (C-only), ‘standard’ PFTs, tech note v0. Version 2 (‘IPCC’ tag) ? Access for any reason including coupled runs. • Consistent with crops, proscribed vegetation, harvest & land use change (managed forest, pasture), N cycle, VOCs, dynamic landunits. Timeline • (as of CESM June 2014) Version -1 (EDMERGE branch) Feb 2014 Access for development only • Runs in PTCLM & some global resolutions, sensible fluxes, energy + water balanced (afaik), NetCDF restarts • Version 0 (software engineering tag) May 2014 Access for adding functionality • NetCDF history files, sensible fluxes, balanced energy/water/carbon, sensible memory use, cold & drought phenology, ED compsets, runs @ alternative resolutions & compilers. • Version 1 (science tag) Oct.Nov. Access for model testing and implementation • • CLM fire coupling, Soil BGC (C-only), ‘standard’ PFTs, tech note v0. Version 2 (‘IPCC’ tag) ? Access for any reason including coupled runs. • Consistent with crops, proscribed vegetation, harvest & land use change (managed forest, pasture), N cycle, VOCs, dynamic landunits. Code performance • Global runs operational at f10, T31, f19 resolutions. • Bit-for-bit restarts in point mode. • Global restart capacity not yet operational, thus models not fully spun-up in terms of biomass & distribution (35-70y) • These simulations are at leaf area equilibrium… • Here we use one Plant Functional Type (evergreen C3 broadleaf tree) • Does it produce sensible results? Leaf Area Index Benchmarks • Produces over-estimates in marginal environments • Removed large high bias in closed canopy forests CLM(ED) max LAI • Too much LAI in boreal and marginal forests MODIS max LAI CLM4.5 max LAI MODIS max LAI GPP Benchmarks • Produces over-estimates in northern ecosystems. • Magnitude of fluxes reasonable. • Removed very productive tropical biases • Improved behavior in savannas Gross Photosynthesis: CLM(ED)v0.0 kgC m2 yr-1 Gross Photosynthesis: CLM4.5 kgC m2 yr-1 Gross Photosynthesis: FLUXNET product kgC m2 yr-1 Evapotranspiration Benchmarks • General over-estimate of ET • Maybe due to Ball-Berry parameters? Evapotranspiration: CLM(ED)v0.0 • or…? Wm-2 Evapotranspiration: CLM4.5 Wm-2 Evapotranspiration: FLUXNET product Wm-2 Mean Latent Heat Flux Wm-2 Sensitivity Analysis Is there a structural bias in evaporation? Canopy Evap Transpiration Evapotranspiration: CLM(ED)v0.0 Ground Evap Summary • CLM(ED) is progressing towards the scientifically validated tag later this year. • This does not mean it it scientifically validated! • Early 35 year global runs indicate that reasonable fluxes can be achieved with significantly fewer degrees of freedom than are typically used. • PFT selection process: How do plant distributions emerge from their functional properties? Trait Filtering & Plant Distributions • CLM(ED) was conceived (partly) as a tool to investigate why plants grow where they do • If we have no good explanation of biome boundaries for the present, how can we trust predictions for the future? • 1st generation DGVMs rely partly on empirical climate envelopes, so are not mechanistic hypotheses for distribution. • So, how do plant distributions emerge from plant traits? C4 grass C3 grass Vegetation Distribution • Only difference between c4 and c3 grasses is photosynthesis switch (c3psn) • How does this change affect vegetation distribution? C4 grass C3 grass Cold Deciduous Tree • Added in cold deciduous & evergreen trees • Only change phenology switch & sla. • Deciduous behavior dominates high latitudes.
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