| Title | Modelling CO 2 and energy exchanges in a northern semiarid grassland using the carbon- and nitrogen-coupled Canadian Land Surface Scheme (C-CLASS) |
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| Author | Zhang, Y; Grant, R F; Flanagan, L B; Wang, S ; Verseghy, D L |
| Source | Ecological Modelling vol. 181, no. 4, 2005 p. 591-614, https://doi.org/10.1016/j.ecolmodel.2004.07.007 |
| Year | 2005 |
| Alt Series | Natural Resources Canada, Contribution Series 20181777 |
| Publisher | Elsevier BV |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | geophysics; remote sensing |
| Program | Canada Centre for Remote Sensing Divsion |
| Released | 2005 02 01 |
| Abstract | The development of carbon (C) and nitrogen (N) simulations is one of the ongoing efforts in the land surface schemes of climate models. The C- and N-coupled Canadian Land Surface Scheme (C-CLASS) was
recently modified to better represent grassland ecosystems. Improvements include revised plant growth and senescence calculations that are driven by the plant C balance between fixation and respiration, and leaf-out and leaf-fall schemes that are
regulated by the seasonal dynamics of C and N reserves. These revisions were developed to better simulate the stress-related senescence and regrowth of perennials. The model was tested with observations of surface carbon and energy fluxes, soil
temperature and moisture, and plant growth during 3 years of declining precipitation at a northern semiarid grassland near Lethbridge, Alberta, Canada. The R 2 and standard deviations between the simulated and observed half-hourly fluxes were 0.95
and 22.5 W m -2 for net radiation, 0.82 and 42.1 W m -2 for sensible heat, 0.66 and 29.2 W m -2 for latent heat, and 0.63 and 0.95 ?mol C m -2 s -1 for net CO 2 exchange. The model and observations both showed a strong impact of declining
precipitation on annual carbon budgets in this semi-arid grassland. In a wet year (1998, precipitation = 482 mm), the ecosystem acted as a strong C sink (92 g C m -2 modelled and 109 g C m -2 measured from June 20th to December 31st). In a
near-normal year (1999, precipitation = 341 mm), a smaller C sink was indicated (24 g C m -2 modelled and 21 g C m -2 measured). In a dry year (2000, precipitation = 276 mm), the ecosystem acted as a small C source (-18 g C m -2 modelled and -17 g C
m -2 measured) |
| GEOSCAN ID | 312132 |
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