Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems. Sebastiaan Luyssaert with contributions of 40+ research groups

Transcription

1 Relationships between GPP, NPP, NEP, Ra, Rh and Re in forest ecosystems Sebastiaan Luyssaert with contributions of 40+ research groups

2 Introduction 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

3 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

4 The database Consistent NPP data Consistent uncertainty Ancillary information

5 The database Consistent NPP data Consistent uncertainty Ancillary information Expert judgement accounting for : - Applied methodology - Number of observations

6 The database 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

7 Data flux observations 380 sites 130 GPP, Re & NEP 250 NPP 130 Rh & Rs 35 Ra

8 Data gaps For GPP, NPP, NEP & Re need: - Boreal ecosystems - Tropical ecosystems

9 Data gaps For Ra & Rh need: - All biomes except temperate humid

10 Dependence of GPP High GPP: warm wet Low GPP: cold dry

11 Dependence of GPP

12 Dependence of GPP?

13 Dependence of GPP?

14 Dependence of GPP?

15 Global patterns in NPP

16 Dependence of NPP

17 Dependence of GPP, NPP, Re and Rh GPP ~ MAT, LAI, P NPP ~ MAT, LAI, Rg Re ~ MAT, LAI, P Rh ~ MAT,?

18 Dependence of NEP GPP ~ MAT, LAI, P Unmanaged forests NPP ~ MAT, LAI, P Re ~ MAT, LAI, P Rh ~ MAT,? NEP,?

19 Dependence of NEP NEP ~ GPP

20 Dependence of NEP NEP ~ GPP

21 Dependence of NEP NEP? Age sink Management source

22 Dependence of NPP/GPP Ra, insuf. data NPP/GPP

23 Dependence of NPP/GPP NPP/GPP data NPP/GPP max production

24 Dependence of NPP/GPP NPP/GPP unmanaged sites

25 Dependence of NPP/GPP Management > Temp

26 Components of the CO2-balance NPP = fnpp + wnpp + rnpp + mnpp NEP = GPP - Re NECB = NEP non-co2 losses non-resp. CO2 losses + CO2 import/export NBP = NECB

27 Components of the CO2-balance Benchmark for model validation Closure problem

28 Closure of the CO2-balance

29 Components of the C-balance

30 Global CO2-balance Uncertainty when models follow the observations

31 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 Substantial closure terms indicate shortcomings of field-observations

32 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

33 Contributors I. 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