Utilizing tree ring chronologies to reconstruct paleo streamflow: a case study at the alabama-florida state border
This study examined the results from a statistical screening of tree-ring width records to evaluatethe strength of the hydrological signal in dendrochronological records from the Southeastern region of the United States. We used United States Geological Survey (USGS) streamflow data from five gages near the Alabama-Florida border and 74 regional tree-ring chronologies to create and analyze seasonal flow reconstructions. Prescreening methods included correlation and temporal stability analysis of predictors to ensure practical and reliable reconstructions. Seasonal correlation analysis revealed that several regional tree-ring chronologies were significantly correlated (p≤0.05) with March–October streamflow, and stepwise linear regression was used to create the reconstructions. Reconstructions for all five rivers were considered statistically skillful (R2≥0.50), with lengths ranging from 144 to 782 years. The reconstructions were statistically validated using the following parameters: R2 predicted validation, the sign test, the variance inflation factor (VIF), and the Durbin-Watson (D-W) statistic. The long-term streamflow variability was analyzed for the Choctawhatchee, Conecuh, Escambia, and Perdido Rivers and the recent (2000s) drought was identified as being the most severe in the instrumental record. The 2000s drought was also identified as being one of the most severe droughts when compared to the paleo-records developed for all five rivers.