HR: 10:35h
AN: H22A-02    [Abstracts]
TI: Probabilistic Runoff Forecasting using a Limited-Area Ensemble Prediction System
AU: * Verbunt, M
EM: mark.verbunt@env.ethz.ch
AF: Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology (ETH), Winterthurerstr 190, Zurich, 8057 Switzerland
AU: Walser, A
EM: Andre.Walser@meteoswiss.ch
AF: Meteoswiss, Kr\"ahb\"uhlstr 58, Zurich, 8044 Switzerland
AU: Gurtz, J
EM: joachim.gurtz@env.ethz.ch
AF: Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology (ETH), Winterthurerstr 190, Zurich, 8057 Switzerland
AU: Montani, A
EM: a.montani@smr.arpa.emr.it
AF: ARPA-SMR Regional Meteorological Service of Emilia-Romagna, Viale Silvani 6, Bologna, 40122 Italy
AU: Sch\"ar, C
EM: schaer@env.ethz.ch
AF: Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology (ETH), Winterthurerstr 190, Zurich, 8057 Switzerland
AB: A high-resolution atmospheric ensemble forecasting system, based on 51 runs of a Limited Area Model (LAM) has been used to make probabilistic runoff forecasts for the Alpine Rhine basin. The operational European Centre for Medium-Range Weather Forecasts Ensemble Prediction System (ECMWF EPS) provides the initial and boundary conditions for the LAM integrations with the Local Model (LM) for a 5 day forecasting period. The LM runs in a horizontal resolution of 0.09 degree (10 km) and provides output with an hourly interval. Output from this model is used to drive a distributed hydrological model with a resolution of 500 m and a time-step of one hour. Runoff generation in the Precipitation Runoff EVApotranspiration Hydrotope (PREVAH) model is based on the HBV-model. The model further contains modules, which calculate snow and glacier melt, after a combined radiation and temperature index approach. The case-study investigated is the spring 1999 flood event, when a combination of snowmelt and heavy precipitation caused severe floods in Central Europe. The area investigated is the upper part of the Rhine catchment (34550 km2) in Central Europe. This river catchment, characterized by highly complex topography, has an altitude range from 262 m up to 4225 m a.s.l. The hydrological model component has been calibrated for the period 1997-1998 using ground observations, and validated for 1999-2002. This study focuses on the feasibility of ensemble prediction data for runoff forecasting and addresses the predictability of this flood event. Forecast uncertainties are investigated and runoff predictions from the deterministic forecast are compared with those obtained from probabilistic atmospheric forecasts. Further analyses include the changes in predictability when using different quantities of representative members.
DE: 1821 Floods
DE: 1854 Precipitation (3354)
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting