Potomac River 1000 Year May-September Streamflow Reconstruction Maxwell, R.S.; Hessl, A.E.; Cook, E.R.; Pederson, N. Maxwell, R.S. Hessl, A.E. Cook, E.R. Pederson, N. Streamflow Reconstruction hydrology earth science/paleoclimate/climate reconstructions|tree ring (age,null,null,year Common Era,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (streamflow,null,null,cubic meter per second,May-Sep,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/instrumental (streamflow,null,null,cubic meter per second,May-Sep,instrumental,null,null,N,null) earth science/paleoclimate/reconstructions (Point of Rocks>LATITUDE 39.2736>LONGITUDE -77.5431) Mean May-September Potomac River streamflow was reconstructed from 950-2001 using a network of tree ring chronologies (n = 27) representing multiple species. We chose a nested principal components reconstruction method to maximize use of available chronologies backward in time. Explained variance during the period of calibration ranged from 20% to 53% depending on the number and species of chronologies available in each 25 year time step. The model was verified by two goodness of fit tests, the coefficient of efficiency (CE) and the reduction of error statistic (RE). The RE and CE never fell below zero, suggesting the model had explanatory power over the entire period of reconstruction. Beta weights indicated a loss of explained variance during the 1550-1700 period that we hypothesize was caused by the reduction in total number of predictor chronologies and loss of important predictor species. Thus, the reconstruction is strongest from 1700-2001. Frequency, intensity, and duration of drought and pluvial events were examined to aid water resource managers. We found that the instrumental period did not represent adequately the full range of annual to multidecadal variability present in the reconstruction. Our reconstruction of mean May-September Potomac River streamflow was a significant improvement over the Cook and Jacoby (1983) reconstruction because it expanded the seasonal window, lengthened the record by 780 years, and better replicated the mean and variance of the instrumental record. By capitalizing on variable phenologies and tree growth responses to climate, multispecies reconstructions may provide significantly more information about past hydroclimate, especially in regions with low aridity and high tree species diversity. STUDY NOTES: Reconstruction of May through September Potomac River streamflow for 950-2001 AD at the Point of Rocks, Maryland USGS streamflow gauge. The streamflow reconstruction is based on 27 tree ring chronologies representing multiple species from locations in the Appalachian Mountains and east to the Atlantic Coast in Maryland, Pennsylvania, West Virginia, and Virginia. Some of the tree ring chronologies are available in the International Tree-Ring Data Bank: http://www.ncdc.noaa.gov/paleo/treering.html NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Maxwell, R.S. Investigator : Hessl, A.E. Investigator : Cook, E.R. Investigator : Pederson, N. 2012-01-28 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12424 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.xls https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.xls https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.txt English https://www.ncdc.noaa.gov/paleo/study/12424 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.xls https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/usa/potomac2011flow.txt Maxwell, R.S., A.E. Hessl, E.R. Cook, and N. Pederson. 2011. A multispecies tree ring reconstruction of Potomac River streamflow (950-2001). Water Resources Research, Vol. 47, W05512, doi:10.1029/2010WR010019. START YEAR: 950 AD * END YEAR: 2001 AD -77.5431 39.2736 -77.5431 39.2736