:: HYDROLOGIC RESEARCH CENTER : RESEARCH : FORECASTING ::

Research at HRC involves designing, improving, and implementing prediction systems. For example, HRC's hydrologic models are used for real-time flash flood warning, channel and river discharge prediction out to 90 days, as well as future climate simulations spanning decades. Prediction of a given field requires uncertainty estimates to instill confidence and meaning. HRC evaluates estimates with remotely sensed data (radar and satellite) and in-situ data. Statistical and dynamical methods are developed and used for downscaling and full dynamical models are adapted and employed in estimation, sensitivity studies, and validation studies.

Improvements in accuracy, efficiency, applicability, and utility of HRC's forecast models have come largely through research on uncertainty analysis. Research and uncertainty analysis on raw data, data collection schemes, blended combinations of data types, and dynamical and statistical interpolation leads to improved field estimates. Overall model accuracy is improved by identifying and understanding uncertainty in each component, parameter, and input. For instance, research at HRC has identified stable scaling relationships between ensemble flow prediction variability and catchment area that are useful for quantifying prediction uncertainty in small subgauged or ungauged scales. The impacts of model structure and scale are also examined. Uncertainty analysis, model updating and data assimilation are explored in the context of state estimation theory. Research with multi-model ensembles is also used to improve hydrologic model reliability.

Georgakakos, K.P., 2005: Analytical results for operational flash flood guidance, Journal of Hydrology (in press).
Georgakakos, K. P., Graham, N. E., Carpenter, T. M., Georgakakos, A. P. and H. Yao, 2005: "Integrating Climate-Hydrology Forecasts and Multi-Objective Reservoir Management for Northern California". EOS 86(12), 122, 127.
Tsintikidis, D., Georgakakos, K.P., Sperfslage, J.A., Smith, D.E., and T.M. Carpenter, 2002: "Precipitation Uncertainty and Raingauge Network Design within the Folsom Lake Watershed," ASCE Journal of Hydrologic Engineering, 7(2), 175-184. (Abstract)
Carpenter, T.M., and K.P. Georgakakos, 2001: "Assessment of Folsom Lake Response to Historical and Potential Future Climate Scenarios, 1. Forecasting," Journal of Hydrology, 249, 148-175, 2001.(Abstract)
Carpenter, T.M., K.P. Georgakakos, and J.A. Sperfslage, 2001: "On the Parametric and Nexrad-Radar Sensitivities of a Distributed Hydrologic Model Suitable for Operational Use," Journal of Hydrology, 253, 169-193. (Abstract)
Georgakakos, K.P., and D.E. Smith, 2001: "Soil Moisture Tendencies into the Next Century for the Conterminous United States," Journal of Geophysical Research - Atmospheres, 106(D21), 27,367-27,382.(Abstract)
Georgakakos, K.P., 2000: "Covariance propagation and updating in the context of real-time radar data assimilation by quantitative precipitation forecast models," Journal of Hydrology, 239, 115-129. (Abstract)
Georgakakos, A. P., H. Yao, M.G. Mullusky and K.P. Georgakakos, 1998: "Impacts of climate variability on the operational forecast and management of the upper Des Moines River basin," Water Resources Research, 4(34), 799-821.
Huang, J., van den Dool, H.M., and K.P. Georgakakos, 1996: "Analysis of Model-Calculated Soil Moisture over the U.S. (1931-93) and Applications in Long-Range Temperature Forecasts," J. of Climate, 9(6), 1350-1362.(Abstract)
Lee, T.H., and K.P. Georgakakos, 1996: "Operational Rainfall Prediction on Meso-g Scales for Hydrologic Applications," Water Resources Research, 32(4), 987-1003. (Abstract)
Bae, D.H., Georgakakos, K.P., and Nanda, S.K., 1995: "Operational Forecasting with Real-Time Databases," in ASCE J. Hydraulics Division, 121(1), 49-60. (Abstract)

Forecasting and Uncertainty