White River, Arkansas 963-Year Streamflow Reconstruction Cleaveland, M.K. Cleaveland, M.K. 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,ring width,null,cubic meter per second,Jun-Aug,climate reconstructions|tree ring,null,regression analysis,N,x1e3 units; simple linear regression) earth science/paleoclimate/instrumental (streamflow,null,null,cubic meter per second,Jun-Aug,instrumental,null,null,N,x1000 m3/s) earth science/paleoclimate/climate reconstructions|tree ring (streamflow,ring width,null,cubic meter per second,Jun-Aug,climate reconstructions|tree ring,smoothed,regression analysis,N,x1e3 units; variance reduced over part of record; calibration data set: local instrumental data; simple linear regression) earth science/paleoclimate/reconstructions (Clarendon>LATITUDE 34.686>LONGITUDE -91.3154) An average of three baldcypress (Taxodium distichum) ring-width chronologies was used to reconstruct total summer (JJA) mean daily flow of the White River at Clarendon, Arkansas, for years 1023-1985. A quadratic transformation of the tree-ring data accounted for 68% (R2 adjusted for degrees of freedom lost) when regressed against total summer flow 1931-1985. The distribution of the quadratic reconstruction matched the gauged distribution much better than a simple linear model which only accounted for 62% of the variance. The model was validated by comparing regression estimates against independent data. Years with summer flow below the 25th percentile occur nonrandomly, i.e., they tend to cluster, in both the reconstructed and gauged data. Hydrologic regimes have apparently varied considerably in the past on annual to century time-scales, with extended dry and wet periods that exceeded anything in the modern record. The frequency of both wet and dry extremes has varied considerably over the last millennium. The eleventh through thirteenth centuries were not analysed due to reduced replication, but the well-replicated fourteenth and twentieth centuries both have large numbers of extremes. The twentieth century appears to have more extreme low flows than the previous centuries and also to have a large number of high flows. The practical consequences for society of variation in extremes and persistence of low flows may be considerable. Climatic change or anthropogenic changes to the watershed (e.g., widespread upland clearing for agriculture and logging of bottomland forests) may be responsible for the change in hydrologic regime during the twentieth century. STUDY NOTES: Reconstructed June/July/August streamflow, White River, AR (cubic meter/second, divided by 1000) NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Cleaveland, M.K. 2004-03-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/6219 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/southusa/whiteriver_flow.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/southusa/whiteriver_flow.txt English https://www.ncdc.noaa.gov/paleo/study/6219 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/southusa/whiteriver_flow.txt M. K. Cleaveland2000A 963-year reconstruction of summer (JJA) stream flow in the White River, Arkansas, USA, from tree-ringsThe Holocene101133-4110.1191/095968300666157027http://hol.sagepub.com/content/10/1/33.abstract START YEAR: 1023 AD * END YEAR: 1985 AD -91.3154 34.686 -91.3154 34.686