 |
| Titel |
Constraining ecosystem carbon dynamics in a data-limited world: integrating ecological "common sense" in a model–data fusion framework |
| VerfasserIn |
A. A. Bloom, M. Williams |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 5 ; Nr. 12, no. 5 (2015-03-03), S.1299-1315 |
| Datensatznummer |
250117838
|
| Publikation (Nr.) |
 copernicus.org/bg-12-1299-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Many of the key processes represented in global terrestrial carbon models
remain largely unconstrained. For instance, plant allocation patterns and
residence times of carbon pools are poorly known globally, except perhaps at
a few intensively studied sites. As a consequence of data scarcity, carbon
models tend to be underdetermined, and so can produce similar net fluxes with
very different parameters and internal dynamics. To address these problems,
we propose a series of ecological and dynamic constraints (EDCs) on model
parameters and initial conditions, as a means to constrain ecosystem variable
inter-dependencies in the absence of local data. The EDCs consist of a range
of conditions on (a) carbon pool turnover and allocation ratios, (b) steady-state proximity, and (c) growth and decay of model carbon pools. We use
a simple ecosystem carbon model in a model–data fusion framework to determine
the added value of these constraints in a data-poor context. Based only on
leaf area index (LAI) time series and soil carbon data, we estimate net
ecosystem exchange (NEE) for (a) 40 synthetic experiments and (b) three
AmeriFlux tower sites. For the synthetic experiments, we show that EDCs lead
to an overall 34% relative error reduction in model parameters, and
a 65% reduction in the 3 yr NEE 90% confidence range. In
the application at AmeriFlux sites all NEE estimates were made independently
of NEE measurements. Compared to these observations, EDCs resulted in
a 69–93% reduction in 3 yr cumulative NEE median biases
(–0.26 to +0.08 kg C m−2), in comparison to standard
3 yr median NEE biases (–1.17 to −0.84 kg C m−2). In
light of these findings, we advocate the use of EDCs in future model–data
fusion analyses of the terrestrial carbon cycle. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|