 |
| Titel |
The influence of competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0 |
| VerfasserIn |
Joe Melton, Vivek Arora |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104602
|
| Publikation (Nr.) |
 EGU/EGU2015-4031.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component
in the earth system modelling framework of the Canadian Centre for Climate Modelling and
Analysis (CCCma). In its current framework, CTEM uses prescribed fractional coverage of
plant functional types (PFTs) in each grid cell. In reality, vegetation cover is continually
adjusting to changes in climate, atmospheric composition, and anthropogenic forcing,
for example, through human-caused fires and CO2 fertilization. These changes
in vegetation spatial patterns occur over timescales of years to centuries as tree
migration is a slow process and vegetation distributions inherently have inertia.
Here, we present version 2.0 of CTEM that includes a representation of competition
between PFTs through a modified version of the Lotka-Volterra (L-V) predator-prey
equations. The simulated areal extents of CTEM’s seven non-crop PFTs are compared
with available observation-based estimates, and simulations using unmodified L-V
equations (similar to other models like TRIFFID), to demonstrate that the model
is able to represent the broad spatial distributions of its seven PFTs at the global
scale. Differences remain, however, since representing the multitude of plant species
with just seven non-crop PFTs only allows the large scale climatic controls on the
distributions of PFTs to be captured. As expected, PFTs that exist in climate niches are
difficult to represent either due to the coarse spatial resolution of the model and the
corresponding driving climate or the limited number of PFTs used to model the
terrestrial ecosystem processes. The geographic and zonal distributions of primary
terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and
dynamically simulated fractional coverage of PFTs compare reasonably with each other
and observation-based estimates. These results illustrate that the parametrization
of competition between PFTs in CTEM behaves in a reasonably realistic manner
while the use of unmodified L-V equations results in unrealistic plant distributions. |
|
|
|
|
|
|