noaa-recon-11205 North American Cordillera 1600 Year Snowpack Reconstructions Pederson, G.T.; Gray, S.T.; Woodhouse, C.A.; Betancourt, J.L.; Fagre, D.B.; Littell, J.S.; Watson, E.; Luckman, B.H.; Graumlich, L.J. North American Cordillera 1600 Year Snowpack Reconstructions 2011-06-09 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/11205 Investigator G.T. Pederson Investigator S.T. Gray Investigator C.A. Woodhouse Investigator J.L. Betancourt Investigator D.B. Fagre Investigator J.S. Littell Investigator E. Watson Investigator B.H. Luckman Investigator L.J. Graumlich 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 instrumental snow water equivalent,null,null,standard deviation unit,Apr,instrumental,null,null,N,April 1 SWE earth science paleoclimate climate reconstructions|tree ring snow water equivalent,ring width,null,standard deviation unit,Apr,climate reconstructions|tree ring,composited|smoothed,null,N,April 1; 20 year cubic smoothing spline (50% frequency cut-off) earth science paleoclimate climate reconstructions|tree ring snow water equivalent,ring width,null,standard deviation unit,Apr,climate reconstructions|tree ring,composited,null,N,"composite April 1 SWE reconstruction built using ""standard"" chronologies (i.e. autocorrelation preserved), and extended using successively longer versions of the reconstrution that have had their mean and variance scaled to equal the ""best"" reconstruction" earth science paleoclimate tree ring age,null,null,year Common Era,null,tree ring,null,null,N,null earth science paleoclimate tree ring total ring width,null,null,millimeter,null,tree ring,null,null,N,units are 0.01 mm if end-of-series marker is 999 and 0.001 mm if end-of-series marker is -9999 earth science paleoclimate climate reconstructions|tree ring snow water equivalent,ring width,null,standard deviation unit,Apr,climate reconstructions|tree ring,composited|smoothed,null,N,April 1; 50 year cubic smoothing spline (50% frequency cut-off) earth science paleoclimate reconstructions streamflow geoscientificInformation Other Hydroclimate Reconstruction drought 369 AD 2009 AD 1581 cal yr BP -59 cal yr BP Complete 36 49 -117 -105 Continent North America North American Cordillera>LATITUDE 44.5>LONGITUDE -111 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Gregory T. Pederson, Stephen T. Gray, Connie A. Woodhouse, Julio L. Betancourt, Daniel B. Fagre, Jeremy S. Littell, Emma Watson, Brian H. Luckman, Lisa J. Graumlich 2011 Science 333 6040 332-335 10.1126/science.1201570 http://science.sciencemag.org/content/333/6040/332

In western North America, snowpack has declined in recent decades, and further losses are projected through the 21st century. Here, we evaluate the uniqueness of recent declines using snowpack reconstructions from 66 tree-ring chronologies in key runoff-generating areas of the Colorado, Columbia, and Missouri River drainages. Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the northern Rocky Mountains and in their north-south synchrony across the cordillera. Both the snowpack declines and their synchrony result from unparalleled springtime warming that is due to positive reinforcement of the anthropogenic warming by decadal variability. The increasing role of warming on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States. STUDY NOTES: Tree-ring based reconstructions of annual snow water equivalent (SWE) contained in drainage basins of the North American Cordillera for the last 1600 years. Reconstructions data are available in two Excel data files for the Northern and Southern Cordillera: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera-north2011swe.xls ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera-south2011swe.xls Supplementary Tables containing site locations, formulas, and statistics are available in a separate Excel file: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera2011swe-suppl.xls The 66 tree ring width data sets utilized in this study are listed in Table S3, and are available in the International Tree Ring Data Bank: http://www.ncdc.noaa.gov/paleo/treering.html and in a ZIP archive file for this study: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera2011rwl.zip

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/readme-cordillera2011swe.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera-north2011swe.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera-south2011swe.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera2011swe-suppl.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/northamerica/cordillera2011rwl.zip USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11