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Two decades of terrestrial carbon fluxes from a carbon cycle data assimilation system (CCDAS)

Rayner, Peter J. ; Scholze, Marko LU ; Knorr, Wolfgang LU ; Kaminski, Thomas ; Giering, Ralf and Widmann, Heiner (2005) In Global Biogeochemical Cycles 19(2). p.1-20
Abstract

This paper presents the space-time distribution of terrestrial carbon fluxes for the period 1979-1999 generated by a terrestrial carbon cycle data assimilation system (CCDAS). CCDAS is based around the Biosphere Energy Transfer Hydrology model. We assimilate satellite observations of photosynthetically active radiation and atmospheric CO2 concentration observations in a two-step process. The control variables for the assimilation are the parameters of the carbon cycle model. The optimized model produces a moderate fit to the seasonal cycle of atmospheric CO2 concentration and a good fit to its interannual variability. Long-term mean fluxes show large uptakes over the northern midlatitudes and uptakes over tropical... (More)

This paper presents the space-time distribution of terrestrial carbon fluxes for the period 1979-1999 generated by a terrestrial carbon cycle data assimilation system (CCDAS). CCDAS is based around the Biosphere Energy Transfer Hydrology model. We assimilate satellite observations of photosynthetically active radiation and atmospheric CO2 concentration observations in a two-step process. The control variables for the assimilation are the parameters of the carbon cycle model. The optimized model produces a moderate fit to the seasonal cycle of atmospheric CO2 concentration and a good fit to its interannual variability. Long-term mean fluxes show large uptakes over the northern midlatitudes and uptakes over tropical continents partly offsetting the prescribed efflux due to land use change. Interannual variability is dominated by the tropics. On interannual timescales the controlling process is net primary productivity (NPP) while for decadal changes the main driver is changes in soil respiration. An adjoint sensitivity analysis reveals that uncertainty in long-term storage efficiency of soil carbon is the largest contributor to uncertainty in net flux.

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author
; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
in
Global Biogeochemical Cycles
volume
19
issue
2
article number
GB2026
pages
20 pages
publisher
American Geophysical Union (AGU)
external identifiers
  • scopus:27644496017
ISSN
0886-6236
DOI
10.1029/2004GB002254
language
English
LU publication?
no
id
165b6a41-96d1-48b4-96f6-499ed5f4f4c5
date added to LUP
2019-03-14 21:29:51
date last changed
2020-09-30 06:02:22
@article{165b6a41-96d1-48b4-96f6-499ed5f4f4c5,
  abstract     = {<p>This paper presents the space-time distribution of terrestrial carbon fluxes for the period 1979-1999 generated by a terrestrial carbon cycle data assimilation system (CCDAS). CCDAS is based around the Biosphere Energy Transfer Hydrology model. We assimilate satellite observations of photosynthetically active radiation and atmospheric CO<sub>2</sub> concentration observations in a two-step process. The control variables for the assimilation are the parameters of the carbon cycle model. The optimized model produces a moderate fit to the seasonal cycle of atmospheric CO<sub>2</sub> concentration and a good fit to its interannual variability. Long-term mean fluxes show large uptakes over the northern midlatitudes and uptakes over tropical continents partly offsetting the prescribed efflux due to land use change. Interannual variability is dominated by the tropics. On interannual timescales the controlling process is net primary productivity (NPP) while for decadal changes the main driver is changes in soil respiration. An adjoint sensitivity analysis reveals that uncertainty in long-term storage efficiency of soil carbon is the largest contributor to uncertainty in net flux.</p>},
  author       = {Rayner, Peter J. and Scholze, Marko and Knorr, Wolfgang and Kaminski, Thomas and Giering, Ralf and Widmann, Heiner},
  issn         = {0886-6236},
  language     = {eng},
  month        = {06},
  number       = {2},
  pages        = {1--20},
  publisher    = {American Geophysical Union (AGU)},
  series       = {Global Biogeochemical Cycles},
  title        = {Two decades of terrestrial carbon fluxes from a carbon cycle data assimilation system (CCDAS)},
  url          = {http://dx.doi.org/10.1029/2004GB002254},
  doi          = {10.1029/2004GB002254},
  volume       = {19},
  year         = {2005},
}