Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 9 3 2005 10.5194/hess-9-209-2005 http://www.hydrol-earth-syst-sci.net/9/209/2005/ http://www.hydrol-earth-syst-sci.net/9/209/2005/hess-9-209-2005.html http://www.hydrol-earth-syst-sci.net/9/209/2005/hess-9-209-2005.pdf 209 224 2005-09-20 Using a spatio-temporal dynamic state-space model with the EM algorithm to patch gaps in daily riverflow series B. A. Amisigo N. C. van de Giesen Center for Development Research, Bonn University, Bonn, Germany Delft University of Technology, Delft, Netherlands A spatio-temporal linear dynamic model has been developed for patching short gaps in daily river runoff series. The model was cast in a state-space form in which the state variable was estimated using the Kalman smoother (RTS smoother). The EM algorithm was used to concurrently estimate both parameter and missing runoff values. Application of the model to daily runoff series in the Volta Basin of West Africa showed that the model was capable of providing good estimates of missing runoff values at a gauging station from the remaining time series at the station and at spatially correlated stations in the same sub-basin.