From Tree Rings to Streamflow: Reconstructing the Hydroclimatic History of the Mississippi River Basin Over the Past Millennia

The Mississippi River Basin (MRB) is the largest watershed in the United States and the primary driver of the county's hydroclimate. To better understand and predict processes within the watershed, this research examines the streamflow history of the MRB and uses it to gain insights into past climate. We used 51 river gauges throughout the MRB and the North American Drought Atlas (NADA) -- a tree-ring-based summer reconstruction of the self-calibrating Palmer Drought Severity on a 0.5° centered over North America -- to reconstruct past streamflow for the selected stations. We successfully reconstructed streamflow from the years 1200 – 2005 using the principal components regression program. Verification statistics at each station indicated significant skill over the entire domain. In applying cluster analysis to the resulting streamflow reconstruction, we identified three distinguishable regimes of streamflow variability within the MRB. These results will be discussed in the context of corresponding large-scale dynamic climate drivers.