HR: 0800h
AN: H21E-0804    [Abstracts]
TI: A Validation Study of the NWS/MPE Precipitation Products Using a Dense Rain Gauge Network in South Louisiana
AU: * Larson, B F
EM: bfl9076@louisiana.edu
AF: Center for Louisiana Inland Water Studies, Dept. of Civil Engineering, University of Louisiana at Lafayette, P.O. Box 42991, Lafayette, LA 70504, United States
AU: Habib, E
EM: habib@louisiana.edu
AF: Center for Louisiana Inland Water Studies, Dept. of Civil Engineering, University of Louisiana at Lafayette, P.O. Box 42991, Lafayette, LA 70504, United States
AU: Graschel, J
EM: jeffrey.graschel@noaa.gov
AF: Lower Mississippi River Forecast Center, National Weather Service, 62300 Airport Road, Slidell, LA 70460, United States
AU: Nelson, B R
EM: brian.nelson@noaa.gov
AF: NOAA National Climatic Center, 151 Patton Ave., Asheville, NC 28801, United States
AB: This study focuses on validation of the multi-sensor precipitation products developed by the operational multi- sensor precipitation estimation (MPE) algorithm of the National Weather Service (NWS) River Forecast Centers (RFC). MPE data are acquired through the Stage IV archives at the National Center for Environmental Prediction (NCEP). MPE data, which is based upon the merging of data from WSR-88D radar, surface rain gauge, and occasionally geo-stationary satellite data, is provided at hourly temporal resolution and over a national Hydrologic Rainfall Analysis Project (HRAP) grid which has a nominal size of 4 square kilometers. Operational hydrologic forecasting applications now require higher spatial and temporal resolution which is provided by radar data. To help determine the validity of radar data in south Louisiana, a study was performed on MPE data for a three-year period (2004-2006) using 13 independently operated rain gauges located within an area of ~30 km2. The close proximity of gauge sites to each other allows for multiple gauges to be located within the same HRAP pixel. As a result, two pixels contained four gauges each, and one pixel contained two gauges. This co-location of multiple gauges within an HRAP pixel allows for a reasonably accurate estimation of the MPE errors over different scales such as hourly, daily, and monthly temporal resolution. In this context, the errors are defined as the deviation of MPE estimates from the corresponding average of gauge measurements in each pixel. The self dependence of these errors is assessed by analyzing their temporal and spatial auto-correlations. The MPE products are mainly intended for operational hydrologic forecasting. Therefore, the study will examine the impact of MPE uncertainties on runoff simulations in a mid-size experimental watershed in south Louisiana. The physically- based hydrologic model (Gridded Surface Subsurface Hydrologic Analysis, GSSHA) is driven by two sets of rainfall forcing: MPE products and data from a dense rain gauge network over the watershed. Differences in the simulated hydrographs are assessed in terms of prediction accuracy of runoff peaks and volumes. Investigating the need for validation of multi-sensor estimates can facilitate the improvement of radar-gauge merging algorithms and further enhance the accuracy of operational hydrologic forecasting.
DE: 1719 Hydrology
DE: 1840 Hydrometeorology
DE: 1853 Precipitation-radar
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: 2007 Fall Meeting