Data assimilation in C cycle science Strand 2 Team
Rationale Problem: Current C models show significant disagreements Complication: Mismatch between GCM grid cells (~270 x 270 Km) and flux footprints (~1 x 1 km) Solution: A model-data framework
Process models -upscaling EO data: -landcover -phenology Flux towers -processes -parameters Geostats -Spatial drivers -Uncertainty Tall tower /aircraft -Check on upscaling -Inversions
Progress Uncertainty in parameter extrapolation from flux towers (REFLEX) Improved modelling of deciduous systems using EO Assimilating reflectance data into C models Generating spatial errors for drivers Using tall towers to constrain C models
REgional Flux Estimation eXperiment (REFLEX) To compare the strengths and weaknesses of various MDF/DA techniques To quantify errors and biases introduced when extrapolating fluxes
REgional Flux Estimation eXperiment (REFLEX) FluxNet data MODIS MDF Full analysis Model parameters DALEC model Training Runs Deciduous forest sites Coniferous forest sites Assimilation Output
REgional Flux Estimation eXperiment (REFLEX) FluxNet data MODIS MDF Full analysis Model parameters DALEC model Testing site forecasts with limited EO data MDF MODIS Analysis FluxNet data testing Assimilation
GPP C root C wood C foliage C litter C SOM/CWD RaRa AfAf ArAr AwAw LfLf LrLr LwLw RhRh D C labile A tolab A fromlab DALEC
A phenology module allows data assimilation at deciduous sites and an improved capacity to assimilate EO data
Assimilating EO data Last year we showed a capability for assimilating LAI products Now we can assimilate reflectance data And we can cope with snow contamination
Observation operator - GORT Leaf reflectance - PROSPECT Empirical soil reflectance function
Observation operator - GORT Shaded crown Illuminated crown Illuminated soil Shaded soil
Modelled vs. observed reflectance Band 1Band 2
Canopy foliage results No assimilation Assimilating MODIS (bands 1 and 2)
GPP results No assimilation Assimilating MODIS (bands 1 and 2)
NEP results No assimilation Assimilating MODIS (bands 1 and 2)
Uncertainty in spatial variation in key controls on the C cycle, such as meteorology, can be quantified using geostatistical techniques
Planetary Boundary Layer model Canopy Flux model Albedo, LE, Sens. heat, Ts, Evaporation, Transpiration NEP Wind speed, Air temp., PAR, Precipitation, VPD, CO 2 conc. Carbon dynamics model Monte Carlo methods provide a powerful means to invert both flux tower and aircraft data to provide estimates of critical C model parameters
Modelled and measured boundary layer profiles of potential temperature, mixing ratio and CO2 concentration, BOREAS
Retrieving parameters using tower data
Plans Manage, process and publish the outputs of REFLEX Demonstrate regional coupled biosphere- atmosphere model (DALEC-NAME) for tall tower and aircraft inversion