Biosphere Modeling Galina Churkina MPI for Biogeochemistry

Biosphere - Biosphere modeling? … all living and non-living matters which have been affected in any way by life… Vegetation, ecosystems Human impacts

 Types and purposes of vegetation models  Models’ verification  Advantages and issues Vegetation Modeling

Purposes To examine and predict:  plant population dynamics considering competition between individual species  changes in energy flows and biogeochemical cycling of ecosystems  vegetation distribution and its shifts (biogeography models)

Plant population models ( gap models )  To predict plant population dynamics considering:  plant competition  establishment  growth  mortality  Time step - years

 To describe vertical exchange of energy and water fluxes  Vegetation is a “barrier” between land surface and the atmosphere  Carbon flux was added  Time step - seconds Soil-Vegetation-Atmosphere- Transfer

Ecosystem models  Changes in carbon, nitrogen, water fluxes and/or storage of ecosystems  Trees are not defined individually  Climatic inputs + plant physiology/empiric relationships  Time step - days, months, years

D ynamic G lobal V egetation M odels  To examine and predict changes in vegetation distribution  Changes in carbon, water fluxes and/or storage of ecosystems  Time step - months, years

Inputs and outputs after Cramer et al. 1999

How to verify the model results?

Site Level Constraints gC/m 2 /day month Measured data are from Tharand, Germany After parameter optimization

Spatial constrains month Remotely sensed DATA from MODIS LAI simulated with BIOME-BGC model

Global constraints? Effect of industrial N deposition on global normalized NEP and NPP (kgC/m2/yr)

Verification at different scales Global: atmospheric inversions Regional: country statistics (forest inventories,etc.) remote sensing Landsat, MODIS, SeaWiFS Site level: measurements of ecosystem/soil C fluxes, C/N content in vegetation or soil mean residence time of C in soil etc. Vegetation model

Advantages  Simulate responses of ecosystems to regionally heterogeneous  temperature and rainfall anomalies  nitrogen deposition rate  land use  Generate predictions

Issue  Verification of model results at regional and global scales  Simulation of human impacts on ecosystems

Churkina & Running, 1998 Dominant controls for carbon, energy and water fluxes Radiation WaterTemperature

Can we neglect human activities?