275-4 Development of a Sensitivity and Uncertainty Analysis Tool in R for Parametrization of the Apex Model.
See more from this Division: ASA Section: Land Management and Conservation
See more from this Session: Land Management and Conservation Oral
Tuesday, November 8, 2016: 2:20 PM
Phoenix Convention Center North, Room 225 B
Abstract:
Development of a sensitivity and uncertainty analysis tool in R for parametrization of the APEX model
Mansour Talebizadeh; Daniel Moriasi; Amanda Nelson; Prasanna Gowda; Jean Steiner; and Patrick Starks
Hydrologic models are used to simulate the responses of agricultural systems to different inputs
and management strategies to identify alternative management practices to cope up with future
climate and/or geophysical changes. The Agricultural Policy/Environmental eXtender (APEX) is
a model developed to evaluate the impact of different land management strategies at the farm or
small watersheds scales with respect to water availability, soil and water quality, plant growth,
and economics. However, depending on the complexity of the study area, some of the APEX
model parameters that are more sensitive than others (with respect to their effect on model
performance) may require adjustment.
Sensitivity analysis can be used as an effective means for detecting sensitive model parameters
that affect the model performance which in turn could result in model simplification without
compromising the performance of model, effective model calibration, as well as better allocation
of resources regarding measurements of parameters in the study area.
In this study, a flexible software APEXSENSUN was developed (in R language) to streamline the
sensitivity analysis and calibration of the APEX model. The APEXSENSUN provides users with a
wide range of sensitivity analysis methods that can be implemented for different study areas or
goals. The software was applied to Rock Creek watershed, a small agricultural watershed located
in northern Ohio, to detect most sensitive parameters that affect APEXs performance regarding
daily streamflow, total nitrogen, and total phosphorous loads simulation. Overall, the
APEXSENSUN proved to be a very flexible and easy-to-use software for performing sensitivity
analysis and model calibration and is expected to be useful to many practitioners and researchers
to parameterize APEX.
Keywords: APEXSENSUN; sensitivity analysis; uncertainty analysis; model calibration; APEX model; hydrology; water quality
See more from this Division: ASA Section: Land Management and Conservation
See more from this Session: Land Management and Conservation Oral