Dendroclimatic Calibration and Verification Using Regionally Averaged and Single Station Precipitation Data

Abstract

The average ring-width index of two published chronologies from the eastern Tennessee climatic division was used as a single predictor variable in linear regression to reconstruct May June precipitation. Regression equations obtained using regionally averaged precipitation data from stations within the climatic division were compared with regressions obtained using single-station (Knoxville, Tennessee) data for comparable periods. The (regionally averaged) division data always provided the better calibration statistics for the regression equations. When the regressions calibrated using division data were verified with independent data for the climatic division and for Knoxville, the better results were always obtained for the division data. When regressions calibrated using single-station data were verified, the independent division data once again provided better results than the independent Knoxville data. Regionally averaged precipitation data also provided more satisfactory results than single- station data in a similar experiment for central Iowa, and probably provides better results in general for this type of dendroclimatic experiment.