Using Baseflow to Constrain Water Table Depth Simulations in the NCAR Community Land Model (CLM)
Abstract
Several recent studies have shown the importance of representing groundwater in land surface hydrologic simulations. However, optimal methods for model calibration in order to realistically simulate baseflow and groundwater depth have received little attention. Moreover, due to model parameter interactions, various parameter combinations are found to exhibit equifinality in simulated total runoff. In this study a simple lumped groundwater model was incorporated into the Community Land Model (CLM), in which the water table is interactively coupled to soil moisture through the groundwater recharge fluxes. The coupled model (CLMGW) is successfully validated in Illinois against a 22-year (1984~2005) monthly observational dataset. The advantage obtained from incorporating baseflow calibration in addition to traditional calibration based on measured streamflow alone is demonstrated. Using the optimal Pareto parameter sets identified from baseflow and total flow calibration, the flow partitioning and water table depth simulation by the CLMGW are improved, and the equifinality problem is alleviated. For other regions that lack observations of water table depth, the baseflow estimates can be used to enhance parameter estimation. The calibrated CLMGW is applied to the entire US to study the impact of groundwater on land hydrologic memory.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.H33C1454L
- Keywords:
-
- 1829 Groundwater hydrology;
- 1830 Groundwater/surface water interaction;
- 1833 Hydroclimatology;
- 1836 Hydrological cycles and budgets (1218;
- 1655);
- 1843 Land/atmosphere interactions (1218;
- 1631;
- 3322)