PROGRAM TITLE: 	Ecosystem Modeling
ACTIVITY STREAM:	Modeling and Prediction
SCIENCE ELEMENTS:	Ecological Systems/Dynamics and Biogeochemical 
Cycles

 U.S. DEPARTMENT OF AGRICULTURE
Agricultural Research Service

SCIENTIFIC MERIT:  Research is targeted towards developing a suite of 
quantitative simulation models for predicting responses of the major 
agronomic crops and managed ecosystems to ensure a continued abundant 
supply of food and fiber.  This involves:  (1) improving our understanding of 
stomatal activity as it affects photosynthesis and transpiration, especially for 
plants grown in high concentrations of carbon dioxide, (2) developing a 
modular structure for the models to maximize the reuse of computer code, 
and (3) developing methods for aggregating plant-scale models to make 
predictions at regional scale.  These models are intended to:  (1) predict water, 
chemical and energy fluxes between soil, plant and atmosphere, (2) predict 
how solar radiation is partitioned by vegetation into sensible and latent heat 
for improving General Circulation Models, (3) predict how terrestrial 
ecosystems on various soils will respond to changes in environmental factors 
including carbon dioxide concentration, temperature, rainfall, solar radiation, 
and UV-B radiation, (4) enable us to devise strategies for ameliorating 
undesirable effects of climate change, (5) provide farmers with management 
tools for responding to climate change.  Submodels developed in the 
Biogeochemical Dynamics and the Climate and Hydrologic Systems science 
elements will be incorporated in the ecosystem response models.

To enhance this program, the multi-agency terrestrial Ecosystem Regional 
Research and Analysis (TERRA) Laboratory will aggregate models from the 
Ecosystem Modeling, Biogeochemical Dynamics, and Climate and Hydrologic 
Systems elements to provide input to holistic Earth systems models required 
for further development of GCMs.  As GCMs improve in their ability to 
predict regional climate, TERRA will disaggregate GCM results to provide 
realistic scenarios for analyses of effects of global climate change on terrestrial 
ecosystems.  TERRA was initiated in FY92 by USGS of DOI and ARS, FS, and 
SCS of USDA with the intention that it should become a neutral, broadly-based 
institution to develop land models and analyses for the terrestrial 
component of the USGCRP.   

STAKEHOLDERS:   The research will benefit all of society through 
application of research results to insure food and fiber production for the 
Nation on a sustainable basis.

POLICY RELEVANCE:  This research is linked with USDA agencies (FS, 
CSRS, and SCS) and with other CEES agencies as opportunities present 
themselves.  Benefits will primarily be scientific information on which to 
develop policies and aid decision making at local, regional, and national 
scales involving the impact of climate and global change on the sustainability 
of food and fiber supplies and the health of the natural resource base.

PROGRAM CONTACT:  R. Dennis Child    Phone (301)  504-5618     FAX   
(301) 504-6231