noaa-recon-16456 Iowa 340 Year Drought and Precipitation Reconstructions Cleaveland, M.K.; Duvick, D.N. Iowa 340 Year Drought and Precipitation Reconstructions 1994-07-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16456 Investigator M.K. Cleaveland Investigator D.N. Duvick 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 Palmer Drought Severity Index,null,null,dimensionless,Jul,climate reconstructions|tree ring,null,null,N,null earth science paleoclimate climate reconstructions|tree ring precipitation,null,null,inch,Aug-Jul,climate reconstructions|tree ring,null,null,N,state of iowa earth science paleoclimate climate reconstructions|tree ring Palmer Hydrologic Drought Index,null,null,dimensionless,Jun,climate reconstructions|tree ring,null,null,N,null earth science paleoclimate climate reconstructions|tree ring precipitation,null,null,inch,Aug-Jul,climate reconstructions|tree ring,null,null,N,Farmersburg earth science paleoclimate climate reconstructions|tree ring Palmer Hydrologic Drought Index,null,null,dimensionless,Jul,climate reconstructions|tree ring,null,null,N,null earth science paleoclimate climate reconstructions|tree ring Palmer Drought Severity Index,null,null,dimensionless,Jun,climate reconstructions|tree ring,null,null,N,null earth science paleoclimate reconstructions ground water earth science paleoclimate reconstructions precipitation geoscientificInformation Palmer Drought Index Reconstruction Precipitation Reconstruction drought 1640 AD 1982 AD 310 cal yr BP -32 cal yr BP Complete 41 43.5 -97 -90.5 Continent North America United States Of America Iowa Iowa>LATITUDE >LONGITUDE 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 M.K. Cleaveland and D.N. Duvick 1992 Water Resources Research 28 10 2607-2615 10.1029/92WR01562 http://onlinelibrary.wiley.com/doi/10.1029/92WR01562/abstract

Tree ring indices from an expanded network of 17 white oak (Quercus alba) sites in eastern and central Iowa were used to reconstruct state average July Palmer hydrological drought index (PHDI), annual precipitation (previous August to current July), and other climate variables for 1640-1982. We removed nonclimatic variance trends caused by changing sample size and senescent growth. July PHDI correlated better with tree growth than annual precipitation. Occurrence of prolonged droughts throughout the reconstruction suggests that decades like the 1930s occur about twice per century in Iowa. Iowa climate is correlated with the Southern Oscillation Index (SOI) from June in the year of El Nino onset (Yr0) through the next February (Yr+1), with negative SOI (El Nino) associated with wetter conditions. When the June (Yr0) to February (Yr+1) average SOI reaches extremes >= + 1.0 or <=-1.0, it correlates significantly with observed and reconstructed July PHDI (r = -0.37 and -0.56, respectively). Climate during solar cycles centered on sunspot minima alternates between wet and dry regimes that differ by an average of 1.21 units of observed July PHDI and 46.7 mm of annual precipitation for 1877-1982. The solar relationship has been stable since 1640. Combining solar and SOI influences in forecasts may improve prediction of Iowa climate. STUDY NOTES: Reconstructed drought indices (PDSI, PHDI) and precipitation for the state of Iowa for the past 340 years, derived from tree-ring data.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/southusa/iowa.recon Data File; Iowa PDSI, PHDI, and Precipitation Reconstructions USA/NOAA DIF Version 9.8.4 2019-05-30 2019-05-29