Studying land-atmosphere exchange of CO :

Transcription

1 Studying land-atmosphere exchange of CO : potentials and limitations of observational approaches Miguel D. Mahecha, Paul Bodesheim, Jakob Zscheischler, Talie Musavi, Martin Jung,, Markus Reichstein et al.,, Max Planck Institute for Biogeochemistry, Jena, Germany German Centre for Integrative Biodiversity Research (idiv), Leipzig, Germany Michael Stifel Center Jena for Data-Driven and Simulation Science, Jena, Germany November,

2 of our research

3 Global change our common issue Visualization by Ed Hawkins

4 Global change our common issue

5 The terrestrial biosphere Bonan ( ) Science,,.

6 Uncertain future of biosphere responses Ahlström ( ) Environmental Research Letters,,. The total terrestrial carbon pool as simulated by LPJ-GUESS when forced by GCMs and CRU TS. historical data. A positive slope implies a negative NEE (sink of carbon), while a negative slope indicates a positive NEE (source of carbon)..

7 State of the observations of land-atmosphere fluxes

8 CO exchange cycle Schulze ( ) Biogeosciences,,.

9 CO exchange cycle Schulze ( ) Biogeosciences,,.

10 Expansion of in-situ observations: Wofsy et al. ( ) Net Exchange of CO in a Mid-Latitude Forest Science,. The eddy correlation method was used to measure the net ecosystem exchange of carbon dioxide continuously from April to December in a deciduous forest...the annual net uptake was. ±. metric tons of carbon per hectare per year....carbon uptake rates were notably larger than those assumed for temperate forests in global carbon studies. Carbon storage in temperate forests can play an important role in determining future concentrations of atmospheric carbon dioxide. Month (1990 to 1991)

11 Expansion of in-situ observations: x-axis: Hour of the day y-axis: Day of the year

12 Expansion of in-situ observations: x-axis: Hour of the day y-axis: Day of the year

13 Opportunities to characterize global patterns Nonlinear dimensionality reduction of FLUXNET fingerprints (Mahecha et al. (in prep.))

14 How to infer global patterns from point data?

15 From points to the globe

16 From points to the globe Machine learning is the key...(fig. by Reichstein et al. (various))

17 From points to the globe First sub-daily global GPP by Bodesheim et al (in prep.).

18 What specific questions can we address now?

19 Extremes in GPP a 75º N 50º N 25º N T 0º 25º S 50º S Decrease in GPP (kg C) W 180º W 120º W 60º W 0º 60º E 120º E 180º E b 1 c 10 0 Total impact size (Tg C) Area Duration Maximum anomaly Probability of effect of extreme event North America, = 1.74 South America, = 1.77 Europe, = 1.72 Africa, = 1.76 Asia, = 1.75 Oceania, = Total effect of an extreme event, shown as loss of GPP (Mg C) Reichstein et al. ( ) Nature

20 A global picture of C fluxes with observations only?

21 The GEOCARBON attempt: Zscheischler, Mahecha et al ( ) Biogeosciences Discussions.

22 Integrated view of terrestrial & aquatic systems 90 a % b 500 Zscheischler, Mahecha et al. ( ) Biogeoscience Discussions gc m 2 yr

23 % Uncertainty of the observed net CO exchange gc m 2 yr b gc m 2 yr 1 c 100 Zscheischler, Mahecha et al. ( ) Biogeoscience Discussions gc m 2 yr 1

24 I Long-term observatories have an high/global impact beyond their original intention... I In-concert, point and Earth observations allows us to estimate global gross fluxes at high spatiotemporal resolutions. I...allowing us e.g. to infer the relevance of regional processes at the global scale (example of extremes). I Observational synthesis of C fluxes reveals the huge uncertainties at low latitudes.

25 I Long-term observatories have an high/global impact beyond their original intention... I In-concert, point and Earth observations allows us to estimate global gross fluxes at high spatiotemporal resolutions. I...allowing us e.g. to infer the relevance of regional processes at the global scale (example of extremes). I Observational synthesis of C fluxes reveals the huge uncertainties at low latitudes.

26 I Long-term observatories have an high/global impact beyond their original intention... I In-concert, point and Earth observations allows us to estimate global gross fluxes at high spatiotemporal resolutions. I...allowing us e.g. to infer the relevance of regional processes at the global scale (example of extremes). I Observational synthesis of C fluxes reveals the huge uncertainties at low latitudes.

27 I Long-term observatories have an high/global impact beyond their original intention... I In-concert, point and Earth observations allows us to estimate global gross fluxes at high spatiotemporal resolutions. I...allowing us e.g. to infer the relevance of regional processes at the global scale (example of extremes). I Observational synthesis of C fluxes reveals the huge uncertainties at low latitudes.

28 Remark We currently offer PhD & PostDoc positions

29 What is the effect of biotic properties on the ecosystem s photosynthetic?

30 Linking GPP sat with functional traits Obs. need to be synchronized in space and time! For Re PhD thesis by Talie Musavi; Musavi et al. ( ) Ecology and Evolution.

31 Interannual variability of GPP sat Higher stand age and species diversity dampen the interannual variability in GPP sat PhD thesis by Talie Musavi; Musavi et al. (accepted) Nature Ecology & Evolution.