POTENTIAL FOR MIDWESTERN HYDROMETEOROLOGICAL RECONSTRUCTIONS USING NORTH PACIFIC AND MIDWESTERN TREE RING SERIES

The Pacific-North American (PNA) teleconnection pattern is significantly link to moisture variability in the Midwest. Here we investigate the possibility of combining temperature sensitive tree-ring series from the North Pacific with moisture-sensitive series from the Midwest and their potential to reconstruct hydrometeorological series including Ohio stream flow and Lake Erie levels. The North Pacific tree-ring series have been used to reconstruct the North Pacific index (NPI), a Pacific basin sea level pressure index that is highly correlated to the PNA. Midwest tree-rings are used in drought reconstructions.

Preliminary results show strong correlations between spring Lake Erie Levels and coastal North Pacific tree-ring records with a combination of North Pacific series explaining over 50% of the variation in lake levels. Coastal Alaska tree-ring series alone are significantly correlated (r = 0.41), with streamflow for October in Northeast Ohio. The NPI correlates well (r = 0 .48) with streamflow in January, whereas correlations with Midwestern tree ring chronologies are their strongest for August (r = 0 .40). These preliminary results show the complex seasonal variability of climate and tree growth and the potential to reconstruct hydrometeorological variables for the Midwest. Recent tree-ring work in Alaska and Ohio is aimed at extending the chronologies from these areas to produce reconstructions of precipitation and drought in Ohio.