HR: 14:15h
AN: H43E-04    [Abstracts]
TI: Precipitation Ensembles from Single-Value Forecasts for Hydrological Ensemble Forecasting
AU: Demargne, J
EM: Julie.Demargne@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AU: Schaake, J
EM: John.Schaake@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AU: Wu, L
EM: Limin.Wu@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AU: Welles, E
EM: Edwin.Welles@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AU: Herr, H
EM: Hank.Herr@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AU: * Seo, D
EM: Dongjun.Seo@noaa.gov
AF: Hydrology Laboratory, Office of Hydrologic Development, NOAA/National Weather Service, 1325 East-West Highway, Silver Spring, MD 20910 United States
AB: An ensemble pre-processor was developed to produce short-term precipitation ensembles using operational single-value forecasts. The methodology attempts to quantify the uncertainty in the single-value forecast and to capture the skill therein. These precipitation ensemble forecasts could be then ingested in the NOAA/National Weather Service (NWS) Ensemble Streamflow Prediction (ESP) system to produce probabilistic hydrological forecasts that reflect the uncertainty in forecast precipitation. The procedure constructs the joint distribution of forecast and observed precipitation from historical pairs of forecast and observed values. The probability distribution function of the future events that may occur given a particular single-value forecast is then the conditional distribution of observed precipitation given the forecast. To generate individual ensemble members for each lead time and each location, the historical observed values are replaced with values sampled from the conditional distribution given the single-value forecast. The replacement procedure matches the ranks of historical and rescaled values to preserve the space-time properties of observed precipitation in the ensemble traces. Currently, the ensemble pre-processor is being tested and evaluated at four NOAA/NWS River Forecast Centers (RFCs) in the U.S.A. In this contribution, we present the results thus far from the field and retrospective evaluations, and key science issues that must be addressed toward national operational implementation.
DE: 1812 Drought
DE: 1821 Floods
DE: 1854 Precipitation (3354)
DE: 1860 Runoff and streamflow
DE: 1869 Stochastic processes
SC: Hydrology [H]
MN: 2005 Joint Assembly