Disaggregation Procedures for Generating Serially Correlated Flow Vectors

The structure of disaggregation models places severe constraints on the feasible values of the lagged covariance of generated flow vectors. A new and simple class of disaggregation models is presented which employ the Valencia-Schaake disaggregation model structure but allow the models' innovations to be serially correlated. These models can reproduce (1) the covariance matrix of the disaggregated flows, (2) their covariance with the upper level flows, and (3) reasonable approximations to the lag one covariance of the disaggregated flow vectors given the constraints imposed by a disaggregation approach. The Mejia-Rousselle disaggregation model is shown, in general, to fail to reproduce the anticipated variances and covariances of the disaggregated flows because the model and its parameter estimators are not self-consistent. The paper closes with a discussion of practical modeling considerations and of staged disaggregation procedures which reduce the size of multisite multiseason models.

[1]  Jared L. Cohon,et al.  Gains from joint operation of multiple reservoir systems , 1977 .

[2]  T. Cline.  Selecting seasonal streamflow models , 1981 .

[3]  R. Bras,et al.  Real time adaptive closed loop control of reservoirs with the High Aswan Dam as a case study , 1983 .

[4]  Ezio Todini.  The preservation of skewness in linear disaggregation schemes , 1980 .

[5]  D. Lettenmaier,et al.  An operational approach to preserving skew in hydrologic models of long‐term persistence , 1977 .

[6]  J. Stedinger,et al.  Water resource systems planning and analysis , 1981 .

[7]  Keith W. Hipel,et al.  Geophysical model discrimination using the Akaike information criterion , 1981 .

[8]  Jery R. Stedinger,et al.  Fitting log normal distributions to hydrologic data , 1980 .

[9]  Ramona L. Trader,et al.  A Bayesian Technique for Selecting a Linear Forecasting Model , 1983 .

[10]  Estimating correlations in multivariate streamflow models , 1981 .

[11]  N. Draper,et al.  Applied Regression Analysis , 1966 .

[12]  J. Stedinger,et al.  An Annual-Monthly Streamflow Model for Incorporating Parameter Uncertainty into Reservoir Simulation , 1982 .

[13]  Jery R. Stedinger,et al.  Synthetic streamflow generation: 1. Model verification and validation , 1982 .

[14]  J. M. Mejía,et al.  Disaggregation models in hydrology revisited , 1976 .

[15]  A. A. Harms,et al.  An extension to the Thomas‐Fiering Model for the sequential generation of streamflow , 1967 .

[16]  R. Valencia,et al.  Disaggregation processes in stochastic hydrology , 1973 .

[17]  E. Wood,et al.  Identification of multivariate time series and multivariate input‐output models , 1982 .

[18]  P. Tao,et al.  Multistation, multiyear synthesis of hydrologic time series by disaggregation , 1976 .

[19]  R. Srikanthan,et al.  Sequential generation of monthly streamflows , 1978 .

[20]  Choosing among alternative hydrologic regression models , 1979 .

[21]  D. M. Allen.  Mean Square Error of Prediction as a Criterion for Selecting Variables , 1971 .

[22]  J. Stedinger,et al.  Estimation of log-normal quantiles: Monte Carlo results and first-order approximations , 1984 .