Calibration & Validation

Methods

A forward stepwise regression procedure was used to calibrate the observed flow record with a pool of potential predictors consisting of tree-ring chronologies from Colorado and northern New Mexico. The residual chronologies, with the low-order autocorrelation removed, were used. Seven predictor chronologies were selected by the stepwise procedure for the reconstruction model. Validation statistics were computed using a leave-one-out (cross-validation) approach.

Predictor Chronologies: Cathedral Creek (CO), Slickrock (CO), Natural Arch (CO), Gould Reservoir (CO), Las Tablas (CO), Cochetopa Dome (CO), Douglas Pass (CO)

(For explanations of these statistics, see this document (PDF), and also the Reconstruction Case Study page.)

Figure 1. Scatter plot of observed and reconstructed Saguache Creek annual flow, 1915-1997.

Figure 2. Observed (black) and reconstructed (blue) annual Saguache Creek annual flow, 1915-1997. The observed mean is illustrated by the dashed line.