California 1200 Year PDSI and 700 Year Precipitation Reconstructions Griffin, D.; Anchukaitis, K.J. Griffin, D. Anchukaitis, K.J. Palmer Drought Index Reconstruction Precipitation Reconstruction drought 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 (precipitation,null,two root mean square error upper bound,unspecified unit,Oct-Jun,climate reconstructions|tree ring,null,null,N,from regional blue oak tree ring chronology) earth science/paleoclimate/instrumental (precipitation,null,null,dimensionless,Oct-Jun,instrumental,normalized,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (precipitation,null,null,unspecified unit,Oct-Jun,climate reconstructions|tree ring,null,null,N,from regional blue oak tree ring chronology) earth science/paleoclimate/climate reconstructions|tree ring (precipitation,null,one root mean square error upper bound,unspecified unit,Oct-Jun,climate reconstructions|tree ring,null,null,N,from regional blue oak tree ring chronology) earth science/paleoclimate/instrumental (Palmer Drought Severity Index,null,null,dimensionless,Jun-Aug,instrumental,null,null,N,null) earth science/paleoclimate/tree ring (tree ring standardized growth index,null,null,null,null,tree ring,composited,null,N,regional blue oak tree ring chronology) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,one root mean square error upper bound,dimensionless,Jun-Aug,climate reconstructions|tree ring,corrected,null,N,from North American Drought Atlas; mean shifted and variance scaled to match observed PDSI) earth science/paleoclimate/climate reconstructions|tree ring (precipitation,null,one root mean square error lower bound,unspecified unit,Oct-Jun,climate reconstructions|tree ring,null,null,N,from regional blue oak tree ring chronology) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,null,dimensionless,Jun-Aug,climate reconstructions|tree ring,null,null,N,from North American Drought Atlas) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,null,dimensionless,Jun-Aug,climate reconstructions|tree ring,corrected,null,N,from North American Drought Atlas; mean shifted and variance scaled to match observed PDSI) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,two root mean square error lower bound,dimensionless,Jun-Aug,climate reconstructions|tree ring,corrected,null,N,from North American Drought Atlas; mean shifted and variance scaled to match observed PDSI) earth science/paleoclimate/climate reconstructions|tree ring (precipitation,null,two root mean square error lower bound,unspecified unit,Oct-Jun,climate reconstructions|tree ring,null,null,N,from regional blue oak tree ring chronology) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,two root mean square error upper bound,dimensionless,Jun-Aug,climate reconstructions|tree ring,corrected,null,N,from North American Drought Atlas; mean shifted and variance scaled to match observed PDSI) earth science/paleoclimate/climate reconstructions|tree ring (Palmer Drought Severity Index,null,one root mean square error lower bound,dimensionless,Jun-Aug,climate reconstructions|tree ring,corrected,null,N,from North American Drought Atlas; mean shifted and variance scaled to match observed PDSI) earth science/paleoclimate/reconstructions (California Divisions 4-7>LATITUDE >LONGITUDE ) For the past three years (2012-2014), California has experienced the most severe drought conditions in its last century. But how unusual is this event? Here we use two paleoclimate reconstructions of drought and precipitation for Central and Southern California to place this current event in the context of the last millennium. We demonstrate that while 3-year periods of persistent below-average soil moisture are not uncommon, the current event is the most severe drought in the last 1200 years, with single year (2014) and accumulated moisture deficits worse than any previous continuous span of dry years. Tree-ring chronologies extended through the 2014 growing season reveal that precipitation during the drought has been anomalously low but not outside the range of natural variability. The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures. STUDY NOTES: Tree-ring based (blue oak, Quercus douglasii) reconstructions of precipitation (1293-2014 AD) and Palmer Drought Severity Index (PDSI) (800-2014 AD) for California State Climate Divisions 4, 5, 6, and 7 (southern 2/3 of California, roughly south of Sacramento). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Griffin, D. Investigator : Anchukaitis, K.J. 2014-12-09 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/17556 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/california/griffin2015drought.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/california/griffin2015drought.txt English https://www.ncdc.noaa.gov/paleo/study/17556 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/california/griffin2015drought.txt Daniel Griffin and Kevin J. Anchukaitis2014How unusual is the 2012-2014 California drought?Geophysical Research Letters10.1002/2014GL062433http://onlinelibrary.wiley.com/doi/10.1002/2014GL062433/abstract START YEAR: 800 AD * END YEAR: 2014 AD -123 32.5 -114 38.5