Annual and interannual CO 2 exchanges of the terrestrial biosphere: process‐based simulations and uncertainties

Annual and interannual CO 2 exchanges of the terrestrial biosphere: process‐based simulations... 1 Assessments of climate change impacts on the global carbon cycle have to rely on accurate models describing the contribution of the terrestrial biosphere. Interannual climate fluctuations provide an ideal test case for their reliability because results can be checked against atmospheric measurements. 2 Intercomparisons have so far shown rather large discrepancies between the results of different terrestrial ecosystem models, especially for net primary productivity (NPP). Therefore, identification of the processes contributing most to modelling uncertainties is another necessary step towards more reliable predictions. 3 The Biosphere Energy‐Transfer and Hydrology model (BETHY) is used to simulate global photosynthesis, and plant and soil respiration embedded within the full energy and water balance, based on 13 years of meteorological data. A series of sensitivity experiments is defined to assess the effects of estimated global uncertainties in a range of parameters. 4 It is found that modelling uncertainties are responsible for a large range of computed values of global annual NPP, while interannual climate fluctuations create only relatively minor changes. These fluctuations, however, are responsible for imbalances between carbon uptake by and release from the terrestrial biosphere, creating interannual fluctuations of the net biosphere–atmosphere CO2 exchange. Here, different model versions tend to agree with each other, which indicates that the net flux is generally better constrained than average NPP. A comparison with net fluxes derived from atmospheric CO2 data shows a good agreement for most models. 5 The results support the hypothesis that at the time scale of a decade, the terrestrial biosphere causes most of the interannual fluctuations of atmospheric CO2 concentrations, with the tropics playing a dominant role. They also indicate that modelling uncertainties for the net carbon exchanges tend to be less pronounced than for NPP. The method presented here, applied to other modelling studies, should also help in the identification of major uncertainties in biosphere process description, eventually leading to improved predictive capabilities of such models. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Global Ecology Wiley

Annual and interannual CO 2 exchanges of the terrestrial biosphere: process‐based simulations and uncertainties

Global Ecology, Volume 9 (3) – Jun 1, 2000

Loading next page...
 
/lp/wiley/annual-and-interannual-co-2-exchanges-of-the-terrestrial-biosphere-4ejQS1f0wL
Publisher
Wiley
Copyright
Copyright © 2000 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1466-822X
eISSN
1466-8238
D.O.I.
10.1046/j.1365-2699.2000.00159.x
Publisher site
See Article on Publisher Site

Abstract

1 Assessments of climate change impacts on the global carbon cycle have to rely on accurate models describing the contribution of the terrestrial biosphere. Interannual climate fluctuations provide an ideal test case for their reliability because results can be checked against atmospheric measurements. 2 Intercomparisons have so far shown rather large discrepancies between the results of different terrestrial ecosystem models, especially for net primary productivity (NPP). Therefore, identification of the processes contributing most to modelling uncertainties is another necessary step towards more reliable predictions. 3 The Biosphere Energy‐Transfer and Hydrology model (BETHY) is used to simulate global photosynthesis, and plant and soil respiration embedded within the full energy and water balance, based on 13 years of meteorological data. A series of sensitivity experiments is defined to assess the effects of estimated global uncertainties in a range of parameters. 4 It is found that modelling uncertainties are responsible for a large range of computed values of global annual NPP, while interannual climate fluctuations create only relatively minor changes. These fluctuations, however, are responsible for imbalances between carbon uptake by and release from the terrestrial biosphere, creating interannual fluctuations of the net biosphere–atmosphere CO2 exchange. Here, different model versions tend to agree with each other, which indicates that the net flux is generally better constrained than average NPP. A comparison with net fluxes derived from atmospheric CO2 data shows a good agreement for most models. 5 The results support the hypothesis that at the time scale of a decade, the terrestrial biosphere causes most of the interannual fluctuations of atmospheric CO2 concentrations, with the tropics playing a dominant role. They also indicate that modelling uncertainties for the net carbon exchanges tend to be less pronounced than for NPP. The method presented here, applied to other modelling studies, should also help in the identification of major uncertainties in biosphere process description, eventually leading to improved predictive capabilities of such models.

Journal

Global EcologyWiley

Published: Jun 1, 2000

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off