Tuesday, 13 January 2009: 2:15 PM
A omparison of the NWS Distributed Versus Lumped Hydrologic Model
Room 127BC (Phoenix Convention Center)
During the summer of 2007, the Lower Mississippi River Forecast Center implemented the NWS Hydrologic Laboratory's Distributed Hydrologic Model. By accounting for small-scale, spatial and temporal variability of rainfall, the distributed hydrologic model was expected to improve river stage forecast accuracy when compared to a lumped hydrologic model. A calibrated distributed hydrologic model was developed for seven basins and was run in parallel with the lumped, Sacramento Soil Moisture Accounting Model.
Verification and model comparisons of river stage forecasts were computed using the NWS Interactive Verification Program. Statistical parameters were generated and used to measure the accuracy of both hydrologic models. Verification of stage forecast accuracy using the distributed hydrologic model versus the lumped model showed inconsistent results for some of the comparison basins. On a case by case basis, the distributed hydrologic model demonstrated a better ability to model the spatial distribution of rainfall.