The "Living Blended Drought Atlas (LBDA)" North American Drought Reconstruction for the last 2000 years Cook, E.R.; Seager, R.; Heim, R.R.; Vose, R.S.; Herweijer, C.; Woodhouse, C.A. Cook, E.R. Seager, R. Heim, R.R. Vose, R.S. Herweijer, C. Woodhouse, C.A. Palmer Drought Index Reconstruction 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 (sample identification,null,null,null,null,climate reconstructions|tree ring,null,null,N,gridpoint number) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,null,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,verification coefficient of determination,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/instrumental (Palmer Modified Drought Index,null,null,dimensionless,null,instrumental,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,verification reduction of error,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,verification root mean square error,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,calibration leave-one-out cross-validation reduction of error,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (latitude,null,null,degree north,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (longitude,null,null,degree east,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,verification coefficient of efficiency,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Modified Drought Index,null,calibration coefficient of determination,dimensionless,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/reconstructions (North America and northern Central America>LATITUDE >LONGITUDE ) IPCC Assessment Report 4 model projections suggest that the subtropical dry zones of the world will both dry and expand poleward in the future due to greenhouse warming. The US Southwest is particularly vulnerable in this regard and model projections indicate a progressive drying there out to the end of the 21st century. At the same time, the USA has been in a state of drought over much of the West for about 10 years now. While severe, this turn of the century drought has not yet clearly exceeded the severity of two exceptional droughts in the 20th century. So while the coincidence between the turn of the century drought and projected drying in the Southwest is cause for concern, it is premature to claim that the model projections are correct. At the same time, great new insights into past drought variability over North America have been made through the development of the North American Drought Atlas from tree rings. Analyses of this drought atlas have revealed past megadroughts of unprecedented duration in the West, largely in the Medieval period about 1000 years ago. A vastly improved Living Blended Drought Atlas (LBDA) for North America now under develop- ment reveals these megadroughts in far greater detail. The LBDA indicates the occurrence of the same Medieval megadroughts in the West and similar-scale megadroughts in the agriculturally and commercially important Mississippi Valley. Possible causes of these megadroughts and their implications for the future are discussed. STUDY NOTES: A high-resolution North American drought atlas reconstructed from tree rings Provided Keywords: North American drought, tree rings, megadroughts, pluvials, PDSI NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Cook, E.R. Investigator : Seager, R. Investigator : Heim, R.R. Investigator : Vose, R.S. Investigator : Herweijer, C. Investigator : Woodhouse, C.A. 2015-07-29 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19119 https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons_cal:ver_stats.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_data.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_metadata.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/nada_hd2_cl.nc https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons_cal:ver_stats.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_data.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_metadata.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/nada_hd2_cl.nc English https://www.ncdc.noaa.gov/paleo/study/19119 https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons_cal:ver_stats.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_JJA_Recons.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_data.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/LBDA_PMDI_Instrumental_metadata.txt https://www1.ncdc.noaa.gov/pub/data/paleo/drought/LBDA2010/nada_hd2_cl.nc Cook, E.R., Seager, R., Heim, R.R., Vose, R.S., Herweijer, C., and Woodhouse, C.2010Megadroughts in North America: Placing IPCC projections of hydroclimatic change in a long-term paleoclimate contextJournal of Quaternary Science25148-6110.1002/jqs.1303 START YEAR: 0 AD * END YEAR: 2005 AD -170 9 -50 72