Post on 27-Dec-2015
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Sebastiaan Luyssaert
with contributions of 40+ research groups
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• Forest play an important role in the global C-cycle
• Since 1970 ongoing effort to estimate production and respiration
• Considerable uncertainties remain
• Assembled a comprehensive global database
Introduction
Objectives
• Explain some important feature of the database
• Identify data gaps
• Present relationships GPP, NPP, NEP, Ra, Rh and Re
• Present CO2-budgets per biome
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Sebastiaan Luyssaert and contributions of 40+ research groups
The database
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• Consistent NPP data
• Consistent uncertainty
• Ancillary information
Sebastiaan Luyssaert and contributions of 40+ research groups
The database
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Expert judgement accounting for :
- Applied methodology
- Number of observations
• Consistent NPP data
• Consistent uncertainty
• Ancillary information
Sebastiaan Luyssaert and contributions of 40+ research groups
The database
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• Consistent NPP data
• Consistent uncertainty
• Ancillary information
- Coordinates, elevation, climatic region,
growth form, management, tree species- Observed MAT, APS, LAI, age, height,
BA, diameter, density, biomass- Monthly temperature, precipitation,
rainy days, cloud cover data CRU- Modelled radiation components, air
humidity, N-deposition, soil composition- NDVI
Sebastiaan Luyssaert and contributions of 40+ research groups
Data
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• 2000+ flux observations
• 380 sites
• 130 GPP, Re & NEP
• 250 NPP
• 130 Rh & Rs
• 35 Ra
Sebastiaan Luyssaert and contributions of 40+ research groups
Data gaps
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• For GPP, NPP, NEP & Re
need:
- Boreal ecosystems
- Tropical ecosystems
Sebastiaan Luyssaert and contributions of 40+ research groups
Data gaps
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
• For Ra & Rh need:
- All biomes except temperate
humid
Sebastiaan Luyssaert and contributions of 40+ research groups
Dependence of GPP
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Sebastiaan Luyssaert and contributions of 40+ research groups
• High GPP: warm wet
• Low GPP: cold dry
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
?
Dependence of GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
?
Dependence of GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
?
Dependence of GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of GPP, NPP, Re and Rh
• GPP ~ MAT, LAI, P
• NPP ~ MAT, LAI, Rg
• Re ~ MAT, LAI, P
• Rh ~ MAT, ?
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NEP
• NEP ~ GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NEP
• NEP ~ GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NEP
NEP ?
• Age
• Management
Sebastiaan Luyssaert and contributions of 40+ research groups
source
sink
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NPP/GPP
Ra, insuf. data
• NPP/GPP
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NPP/GPP
• NPP/GPP data
• NPP/GPP max
production
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NPP/GPP
NPP/GPP unmanaged
sites
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Dependence of NPP/GPP
Management > Temp
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Components of the CO2-balance
• Benchmark for model validation
• Closure problem
Sebastiaan Luyssaert and contributions of 40+ research groups
Closure of the CO2-balance
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Global CO2-balance
• Uncertainty when models
follow the observations
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
Conclusions
• Database of field-observations available for model validation
• Missing 2 out of 8 climate regions
• Climate dependence of GPP, NPP, Re but not of NEP
• NPP/GPP ratio is not 0.475
• Substantial closure terms indicate shortcomings of field-observations
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
We want more...
• Presentation Denis Lousteau: Management effects on the annual
carbon balance of forests
• Poster Ilaria Inglima: NPP drives Rh in forest ecosystems
• Task force presentations Martin Jung: Comparison of models and
observations
Sebastiaan Luyssaert and contributions of 40+ research groups
Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems
ContributorsI. Inglima, M. Jung, M. Reichstein, D. Papale, S. Piao, E.-D. Schulze, L. Wingate, G. Matteucci, M. Aubinet, C. Beer, C. Bernhofer, K.G. Black, D. Bonal, J.Chambers, P. Ciais, K.J. Davis, E.H. Delucia, A.J. Dolman, A. Don, B. Gielen, J. Grace, A. Granier, A. Grelle, T. Griffis, T. Grünwald, G. Guidolotti, P.J. Hanson, R. Harding, D. Hollinger, P. Kolari, B. Kruijt, W. Kutsch, F. Lagergren, T. Laurila, B. Law, G. Le Maire, A. Lindroth, F. Magnani, M. Marek, J. Mateus, M. Migliavacca, L. Misson, L. Montagnani, J. Moncrieff, E. Moors, J.W. Munger, E. Nikinmaa, D. Loustau, G. Pita, C. Rebmann, A.D. Richardson, O. Roupsard, N. Saigusa, M.J. Sanz, G. Seufert, L. Soerensen, J. Tang, R. Valentini, T. Vesala and I. Janssens
Funding
Belgian Research Foundation (FWO), CarboEurope-IP and Antwerp University
Sebastiaan Luyssaert and contributions of 40+ research groups