noaa-lake-18995 Kurupa Lake, Alaska 5,700 Year Inferred Chlorophyll and Summer Temperature Reconstruction Boldt, B.R.; Kaufman, D.S.; McKay, N.P.; Briner, J.P. Kurupa Lake, Alaska 5,700 Year Inferred Chlorophyll and Summer Temperature Reconstruction 2015-07-09 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/18995 Investigator B.R. Boldt Investigator D.S. Kaufman Investigator N.P. McKay Investigator J.P. Briner earth science paleoclimate climate reconstructions|paleolimnology non-freezing days,null,one standard deviation upper bound,count,Jun-Sep,climate reconstructions|paleolimnology,averaged,null,N,3-year mean; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate paleolimnology age,null,95% confidence interval upper bound,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate climate reconstructions|paleolimnology temperature,null,one standard deviation lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,null,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology non-freezing days,null,one standard deviation lower bound,count,Jun-Sep,climate reconstructions|paleolimnology,averaged,null,N,3-year mean; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology non-freezing days,null,two standard deviations lower bound,count,Jun-Sep,climate reconstructions|paleolimnology,averaged,null,N,3-year mean; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,one standard deviation lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,one standard deviation upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,null,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate paleolimnology depth,null,null,centimeter,null,paleolimnology,null,null,N,null earth science paleoclimate climate reconstructions|paleolimnology age,null,null,calendar year before present,null,climate reconstructions|paleolimnology,null,null,N,null earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology non-freezing days,null,two standard deviations upper bound,count,Jun-Sep,climate reconstructions|paleolimnology,averaged,null,N,3-year mean; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate paleolimnology reflectance,sediment,null,dimensionless,null,paleolimnology,null,spectrophotometry,N,ratio between the reflectance minimum (absorption maximum) and the reflectance value for 660-670nm earth science paleoclimate climate reconstructions|paleolimnology temperature,null,null,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations lower bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology non-freezing days,null,null,count,Jun-Sep,climate reconstructions|paleolimnology,averaged,null,N,3-year mean; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,one standard deviation upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate climate reconstructions|paleolimnology temperature,null,two standard deviations upper bound,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged,null,N,100-year-mean; anomalies relative to 1961-1990; calibrated to 20th Century Reanalysis; based on sediment chlorophyll earth science paleoclimate paleolimnology age,null,95% confidence interval lower bound,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate climate reconstructions|paleolimnology temperature,null,null,degree Celsius,Jun-Sep,climate reconstructions|paleolimnology,anomalized|averaged|smoothed,null,N,3-year-mean smoothed; anomalies relative to 1961-1990; calibrated to GISTEMP reanalysis; based on sediment chlorophyll earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology reconstruction earth science paleoclimate paleolimnology physical properties geoscientificInformation Air Temperature Reconstruction 5698 cal yr BP -60 cal yr BP Complete 68.3637 68.3637 -154.6496 -154.6496 924 924 Continent North America United States Of America Alaska Kurupa Lake>LATITUDE 68.3637>LONGITUDE -154.6496 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 Brandon R. Boldt, Darrell S. Kaufman, Nicholas P. McKay, and Jason P. Briner 2015 The Holocene 25 4 641-650 10.1177/0959683614565929 http://hol.sagepub.com/content/25/4/641.abstract

Quantitative records of pre-industrial temperature changes are fundamental for understanding long-term natural climate variability. We used visible reflectance spectroscopy to measure chlorophyll content (and its derivatives) in a sediment core from Kurupa Lake, north-central Brooks Range, Alaska, to reconstruct summer temperature and the number of annual non-freezing days over the past 5.7 ka. A calibration-in-time approach was used to convert downcore changes in chlorophyll content to the climate variables, and an ensemble approach was used to integrate age and calibration uncertainties. The strongest correlation (r median = 0.69, p median = 0.02, RMSEP = 1.9C) is for summer (June through September) temperature using the 20th Century Reanalysis Project dataset. The chlorophyll-inferred 3-year-mean summer temperature shows that the warmest century (3.0-2.9 ka BP) was about 3.0C (90% range of the ensemble members = 2.3-4.0C) higher and that the coldest century (1.4-1.3 ka BP) was about 5.5C lower (90% range = -7.6C to -5.0C) than during the reference period (AD 1961-1990). Century-to-century temperature changes over the past 5.7 ka at Kurupa Lake have been large (90% range = -2.8C to 3.1C shifts in centennial mean), including the shift between the 19th and 20th centuries, which was above the 90th percentile of temperature changes across all representations of the reconstruction. In contrast to most Northern Hemisphere temperature reconstructions, Kurupa Lake shows no overall millennial-scale cooling trend. We suggest that increased summer duration (by 4.3 days during the last 6 ka) along with no long-term increase in sea-ice cover over the adjacent Chukchi Sea counter-balanced the influence of decreased insolation intensity on the aquatic productivity in Kurupa Lake. STUDY NOTES: Inferred sediment chlorophyll content and summer (June-September) temperature reconstruction from Kurupa Lake, Brooks Range, Alaska, for the past 5.7 ka. Data are spectrally inferred (RABD) chlorophyll concentration, geochronology (14C and 210Pb), and summer temperature reconstructions (3-yr and 100-yr).

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kurupa2015temp3yrrean.txt Data File; Kurupa Lake 3-Year Average Temperature Reconstructions 20th Century Reanalysis GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kurupa2015temp3yrgis.txt Data File; Kurupa Lake 3-Year Average Temperature Reconstructions GISTEMP reanalysis target GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kurupa2015temp3yrnfd.txt Data File; Kurupa Lake Reconstructed Summer Non-Freezing Days GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kurupa2015temp100yr.txt Data File; Kurupa Lake Century Average Temperature Reconstructions GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kurupa2015rabd.txt Data File; Kurupa Lake Relative Absorption Band Depth (RABD) USA/NOAA DIF Version 9.8.4 2019-03-27 2019-03-27