Implications of the El Nino-Southern Oscillation for long-range streamflow forecasting: The Columbia River Basin
The increased demands of water users in the Pacific Northwest region of the United States has also accentuated the need for long range forecasts of streamflow. At present, long range streamflow forecasts are not available to water resource managers. Yet in the Pacific Northwest, a significant lag relationship exists between ENSO (El Nio-Southern Oscillation) and streamflow. Using this lag relationship, this study proposes to extend the prediction of spring-summer runoff in the Pacific Northwest from the current one- to three-month lead time to a three- to seven-month lead time. Presented here is the development of a long range seasonal streamflow forecasting model for the Columbia River Basin. The model uses, as predictors, Persistence in streamflow along with two ENSO indicators: the Southern Oscillation Index (SOI) and the Wright Sea Surface Temperatures (SSTw). A probabilistic streamflow forecast is made from an optimal linear combination of Persistence, SOI Linear Discriminant Analysis (LDA), and SSTw LDA forecasts. Two forms of the forecast are developed a categorical forecast of below normal, normal or above normal streamflow, and an exceedance probability forecast. These two approaches are tested on data from eight Columbia River Basin streamflow stations covering the time period 1911 to 1992. It is encouraging that, at some stations, a three- to seven-month lead time forecast of spring-summer runoff has better skill than Climatology. This information may provide guidance to managers of water resource systems.
Climate | Environmental Sciences | Fresh Water Studies | Natural Resources Management and Policy
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Piechota, T. C.,
Dracup, J. A.
Implications of the El Nino-Southern Oscillation for long-range streamflow forecasting: The Columbia River Basin.
WRPMD'99 : Preparing for the 21st Century
American Society of Civil Engineers.