|
A daily time step version for the soil climate, biogeochemical, and trace gas
components of NASA-CASA has been developed and is currently being validated at
a number of research sites around the world. In order to better represent
localized climate and mineral processes on soil water and nutrient dynamics,
several important modifications are made, including development of moisture and
heat fluxes through layers in the plant-soil environment, and refinement of
microbial responses to wetting-drying episodes. A methane flux component is
being tested for northern wetlands sites.
Major findings
- Model tests in three tropical forest stands over a soil age gradient
(ranging from 200 to 185,000 years old) on the island of Hawaii showed that
simulations correctly predict the observed difference of an order of magnitude
between N2O emission fluxes in the youngest and the oldest forest soils.
- Simulated methane emissions in wetland ecosystems of Alaska and central
Canada (BOREAS sites) correctly predict the seasonal range of CH4 flux, along
with observed water table depth and soil thaw dynamics.
|
Daily Soil Model
|
|
|
References
Potter, C. S. 1997. An ecosystem simulation model for methane production
and emission from wetlands. Global Biogeochemical Cycles. 11: 495-506.
Frolking, S. E., A. R. Moiser, D. S. Ojima, C. Li, W. J. Parton, C. S. Potter,
E. Priesack, R. Stenger, C. Haberbosch, P. Dorsch, H. Flessa, and K. A. Smith.
1998. Comparison of N2O emissions from soils at three temperate agricultural
sites: Simulations of year-round measurements by four models. Nutrient Cycling
in Agroecosystems. (In Press).
Potter C. S., R. H. Riley, and S. A. Klooster. 1997. Simulation modeling of
nitrogen trace gas emissions along an age gradient of tropical forest soils.
Ecological Modeling. 97(3):179-196.
|
