HR: 10:40h
AN: H52A-02 INVITED    [Abstracts]
TI: Complete representation of uncertainty in hydrological forecasts
AU: * Clark, M P
EM: mp.clark@niwa.co.nz
AF: NIWA, 10 Kyle Street, Christchurch, 8004, New Zealand
AB: Probabilistic hydrological forecasts are routinely produced by running a hydrological model up to the start of the forecast period with historical station data to estimate basin initial conditions, and then running the model into the future with an ensemble of weather and climate forecasts. The uncertainty in streamflow forecasts depends on uncertainties in estimates of basin initial conditions, uncertainty in the weather and climate forecasts, and uncertainties in the hydrological model itself. Typically, uncertainty in weather and climate forecasts is the only source of uncertainty considered in operational hydrological forecasts. This paper will describe attempts to provide a complete representation of uncertainty in hydrological forecasts. · We will describe methods to quantify uncertainties in basin initial conditions that stem from uncertainties in interpolated historical station data, and we will describe applications of ensemble data assimilation methods to reduce uncertainties in basin initial conditions. · We will discuss the application and limitations of new methods that we have developed to use multi-model ensembles to quantify uncertainty in hydrological models, and we will compare these methods with the simpler approach of stochastically perturbing model states. · We will describe methods to quantify uncertainty in weather and climate forecasts, and show how information from diverse sources can be integrated to provide probabilistic forecast products on time scales ranging from hours through to seasons. Finally, we will demonstrate how explicit quantification of all these sources of uncertainty is integrated in an operational hydrological forecasting system.
DE: 1805 Computational hydrology
DE: 1816 Estimation and forecasting
DE: 1833 Hydroclimatology
DE: 1840 Hydrometeorology
DE: 1873 Uncertainty assessment (3275)
SC: Hydrology [H]
MN: 2007 Fall Meeting