relationships between gpp, npp, nep, ra, rh and re in forest ecosystems sebastiaan luyssaert with...

Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems

Sebastiaan Luyssaert

with contributions of 40+ research groups

http://www.ua.ac.be/

Sebastiaan Luyssaert and contributions of 40+ research groups


• 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




The database


• Consistent NPP data

• Consistent uncertainty

• Ancillary information



The database


Expert judgement accounting for :

- Applied methodology

- Number of observations






The database





- 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



Data


• 2000+ flux observations

• 380 sites

• 130 GPP, Re & NEP

• 250 NPP

• 130 Rh & Rs

• 35 Ra



Data gaps


• For GPP, NPP, NEP & Re

need:

- Boreal ecosystems

- Tropical ecosystems



Data gaps


• For Ra & Rh need:

- All biomes except temperate

humid



Dependence of GPP



• High GPP: warm wet

• Low GPP: cold dry



Dependence of GPP




?

Dependence of GPP




Dependence of GPP, NPP, Re and Rh

• GPP ~ MAT, LAI, P

• NPP ~ MAT, LAI, Rg

• Re ~ MAT, LAI, P

• Rh ~ MAT, ?




Dependence of NEP

• NEP ~ GPP



Dependence of NEP

NEP ?

• Age

• Management


source

sink



Dependence of NPP/GPP

Ra, insuf. data

• NPP/GPP




• NPP/GPP data

• NPP/GPP max

production




NPP/GPP unmanaged

sites




Management > Temp



Components of the CO2-balance

• Benchmark for model validation

• Closure problem



Closure of the CO2-balance





Global CO2-balance

• Uncertainty when models

follow the observations




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




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



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


relationships between gpp, npp, nep, ra, rh and re in forest ecosystems sebastiaan luyssaert with...

Documents

forest ecosystems forest

research groups high

ra rh need

research groups relationships

rasebastiaan luyssaert

warm wet low gpp

global ccycle

important feature