Climate Signal scores. Length is the period of overlap with instrumental temperature data in years. Correlation is the Pearson correlation coefficient between the tree-ring chronology and the instrumental data over the calibration period. Calibration/verification difference indicates the correlation range between different periods of overlap with instrumental data. Truncation ¼ 0.5 if the calibration period was shortened (e.g. due to divergence), truncation ¼ 1 if this is not the case.